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The GNU Name System
draft-schanzen-gns-07

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This is an older version of an Internet-Draft that was ultimately published as RFC 9498.
Authors Martin Schanzenbach , Christian Grothoff , Bernd Fix
Last updated 2022-02-15 (Latest revision 2022-02-14)
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draft-schanzen-gns-07
Independent Stream                                       M. Schanzenbach
Internet-Draft                                               GNUnet e.V.
Intended status: Informational                               C. Grothoff
Expires: 18 August 2022                            Berner Fachhochschule
                                                                  B. Fix
                                                             GNUnet e.V.
                                                        14 February 2022

                          The GNU Name System
                         draft-schanzen-gns-07

Abstract

   This document contains the GNU Name System (GNS) technical
   specification.  GNS is a decentralized and censorship-resistant name
   system that provides a privacy-enhancing alternative to the Domain
   Name System (DNS).

   This document defines the normative wire format of resource records,
   resolution processes, cryptographic routines and security
   considerations for use by implementers.  It is published here to
   inform readers about the function of GNS, guide future GNS
   implementations, and ensure interoperability among implementations
   including with the pre-existing GNUnet implementation.

   This specification was developed outside the IETF and does not have
   IETF consensus.  It is published here to guide implementation of GNS
   and to ensure interoperability among implementations.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 18 August 2022.

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Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Notation . . . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Zone Top-Level Domain . . . . . . . . . . . . . . . . . .   9
     4.2.  Zone Revocation . . . . . . . . . . . . . . . . . . . . .  10
   5.  Resource Records  . . . . . . . . . . . . . . . . . . . . . .  14
     5.1.  Zone Delegation Records . . . . . . . . . . . . . . . . .  16
       5.1.1.  PKEY  . . . . . . . . . . . . . . . . . . . . . . . .  17
       5.1.2.  EDKEY . . . . . . . . . . . . . . . . . . . . . . . .  20
     5.2.  Redirection Records . . . . . . . . . . . . . . . . . . .  24
       5.2.1.  REDIRECT  . . . . . . . . . . . . . . . . . . . . . .  25
       5.2.2.  GNS2DNS . . . . . . . . . . . . . . . . . . . . . . .  25
     5.3.  Auxiliary Records . . . . . . . . . . . . . . . . . . . .  26
       5.3.1.  LEHO  . . . . . . . . . . . . . . . . . . . . . . . .  26
       5.3.2.  NICK  . . . . . . . . . . . . . . . . . . . . . . . .  27
       5.3.3.  BOX . . . . . . . . . . . . . . . . . . . . . . . . .  28
   6.  Record Storage  . . . . . . . . . . . . . . . . . . . . . . .  29
     6.1.  The Storage Key . . . . . . . . . . . . . . . . . . . . .  29
     6.2.  The Records Block . . . . . . . . . . . . . . . . . . . .  30
   7.  Name Resolution . . . . . . . . . . . . . . . . . . . . . . .  33
     7.1.  Start Zones . . . . . . . . . . . . . . . . . . . . . . .  33
     7.2.  Recursion . . . . . . . . . . . . . . . . . . . . . . . .  34
     7.3.  Record Processing . . . . . . . . . . . . . . . . . . . .  35
       7.3.1.  REDIRECT  . . . . . . . . . . . . . . . . . . . . . .  36
       7.3.2.  GNS2DNS . . . . . . . . . . . . . . . . . . . . . . .  36
       7.3.3.  BOX . . . . . . . . . . . . . . . . . . . . . . . . .  37
       7.3.4.  Zone Delegation Records . . . . . . . . . . . . . . .  38
       7.3.5.  NICK  . . . . . . . . . . . . . . . . . . . . . . . .  38
   8.  Internationalization and Character Encoding . . . . . . . . .  39
   9.  Security and Privacy Considerations . . . . . . . . . . . . .  39

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     9.1.  Availability  . . . . . . . . . . . . . . . . . . . . . .  39
     9.2.  Agility . . . . . . . . . . . . . . . . . . . . . . . . .  39
     9.3.  Cryptography  . . . . . . . . . . . . . . . . . . . . . .  40
     9.4.  Abuse Mitigation  . . . . . . . . . . . . . . . . . . . .  41
     9.5.  Zone Management . . . . . . . . . . . . . . . . . . . . .  41
     9.6.  Impact of DHTs as Underlying Storage  . . . . . . . . . .  42
     9.7.  Revocations . . . . . . . . . . . . . . . . . . . . . . .  42
     9.8.  Label Guessing  . . . . . . . . . . . . . . . . . . . . .  43
   10. GANA Considerations . . . . . . . . . . . . . . . . . . . . .  43
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  45
   12. Implementation and Deployment Status  . . . . . . . . . . . .  45
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  45
   14. Normative References  . . . . . . . . . . . . . . . . . . . .  45
   15. Informative References  . . . . . . . . . . . . . . . . . . .  48
   Appendix A.  Base32GNS  . . . . . . . . . . . . . . . . . . . . .  49
   Appendix B.  Test Vectors . . . . . . . . . . . . . . . . . . . .  50
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  63

1.  Introduction

   The Domain Name System (DNS) [RFC1035] is a unique distributed
   database and a vital service for most Internet applications.  While
   DNS is distributed, in practice it relies on centralized, trusted
   registrars to provide globally unique names.  As the awareness of the
   central role DNS plays on the Internet rises, various institutions
   are using their power (including legal means) to engage in attacks on
   the DNS, thus threatening the global availability and integrity of
   information on the Internet.

   DNS was not designed with security in mind.  This makes it very
   vulnerable, especially to attackers that have the technical
   capabilities of an entire nation state at their disposal.  While a
   wider discussion of this issue is out of scope for this document,
   analyses and investigations can be found in recent academic research
   works including [SecureNS].

   This specification describes a censorship-resistant, privacy-
   preserving and decentralized name system: The GNU Name System (GNS)
   [GNS].  It is designed to provide a secure, privacy-enhancing
   alternative to DNS, especially when censorship or manipulation is
   encountered.  In particular, it directly addresses concerns in DNS
   with respect to "Query Privacy", the "Single Hierarchy with a
   Centrally Controlled Root" and "Distribution and Management of Root
   Servers" as raised in [RFC8324].  GNS can bind names to any kind of
   cryptographically secured token, enabling it to double in some
   respects as even as an alternative to some of today's Public Key
   Infrastructures, in particular X.509 for the Web.

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   The design of GNS incorporates the capability to integrate and
   coexist with DNS.  GNS is based on the principle of a petname system
   and builds on ideas from the Simple Distributed Security
   Infrastructure [SDSI], addressing a central issue with the
   decentralized mapping of secure identifiers to memorable names:
   namely the impossibility of providing a global, secure and memorable
   mapping without a trusted authority.  GNS uses the transitivity in
   the SDSI design to replace the trusted root with secure delegation of
   authority thus making petnames useful to other users while operating
   under a very strong adversary model.

   This is an important distinguishing factor from the Domain Name
   System where root zone governance is centralized at the Internet
   Corporation for Assigned Names and Numbers (ICANN).  In DNS
   terminology, GNS roughly follows the idea of a hyperlocal root zone
   deployment, with the difference that it is not expected that all
   deployments use the same local root zone, and that users can easily
   delegate control of arbitrary domain names to arbitrary zones.

   This document defines the normative wire format of resource records,
   resolution processes, cryptographic routines and security
   considerations for use by implementers.

   This specification was developed outside the IETF and does not have
   IETF consensus.  It is published here to guide implementation of GNS
   and to ensure interoperability among implementations.

1.1.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Terminology

   Label  A GNS label is a label as defined in [RFC8499].  Within this
      document, labels are always assumed to be strings of UTF-8
      characters [RFC8499] with a maximum length of 63 bytes for
      compatibility with applications enforcing DNS legacy limitations.
      Labels MUST be canonicalized using Normalization Form C (NFC)
      [Unicode-UAX15].

   Apex Label  The apex label is represented using the character "@"

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      (without quotes).  The apex label is used to publish resource
      records in a zone that can be resolved without providing a
      specific label.  It is the GNS method to provide what is the "zone
      apex" in DNS [RFC4033].

   Name  A name in GNS is a domain name as defined in [RFC8499] as an
      ordered list of labels.  The labels in a name are separated using
      the character "." (dot).  Names, like labels, are encoded in UTF-
      8.

   Top-Level Domain  The rightmost part of a GNS name is a GNS Top-Level
      Domain (TLD).  A GNS TLD may consist of one or more labels.
      Unlike DNS Top-Level Domains (defined in [RFC8499]), GNS does not
      expect all users to use the same global root zone.  Instead, with
      the exception of Zone Top-Level Domains (see below), GNS TLDs are
      typically part of the configuration of the local resolver (see
      Section 7.1), and may thus not be globally unique.

   Zone  A GNS zone contains authoritative information (resource
      records).  A zone is uniquely identified by its zone key.  Unlike
      DNS zones, a GNS zone does not need to have a SOA record under the
      apex label.

   Zone Type  The type of a GNS zone determines the cipher system and
      binary encoding format of the zone key, blinded zone keys, and
      signatures.

   Zone Key  The zone key uniquely identifies a zone.  The zone key is
      usually a public key of an asymmetric key pair.

   Blinded Zone Key  A blinded zone key is derived from the zone key and
      a label.  The zone key and the blinded zone key are unlinkable
      without knowledge of the label.

   Zone Key Derivation Function  The zone key derivation function (ZKDF)
      blinds a key using a label.  There are different functions for
      public and private keys, respectively.

   Zone Owner  The owner of a GNS zone is the holder of the secret
      (typically a private key) that (together with a label and a value
      to sign) allows the creation of zone signatures that can be
      validated against the respective blinded zone key.

   Zone Top-Level Domain  A GNS Zone Top-Level Domain (zTLD) is a

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      sequence of GNS labels at the end of a GNS name which encodes a
      zone type and zone key of a zone.  Due to the statistical
      uniqueness of zone keys, zTLDs are also globally unique.  A zTLD
      label sequence can only be distinguished from ordinary TLD label
      sequences by attempting to decode the labels into a zone type and
      zone key.

   Resource Record  A GNS resource record is the information associated
      with a label in a GNS zone.  A GNS resource record contains
      information as defined by its resource record type.

   Application  An application refers to a component which uses a GNS
      implementation to resolve names into records and processes its
      contents.

3.  Overview

   In GNS, any user may create and manage one or more cryptographically
   secured zones (Section 4).  Zones are uniquely identified by a zone
   key.  Zone contents are signed using blinded private keys and
   encrypted using derived secret keys.  The zone type determines the
   respective set of cryptographic operations and the wire formats for
   encrypted data, public keys and signatures.

   A zone can be populated with mappings from labels to resource records
   by its owner (Section 5).  A label can be mapped to a delegation
   record which results in the corresponding subdomain being delegated
   to another zone.  Circular delegations are explicitly allowed,
   including delegating a subdomain to its immediate parent zone.  In
   order to support (legacy) applications as well as to facilitate the
   use of petnames, GNS defines auxiliary record types in addition to
   supporting traditional DNS records.

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   Zone contents are encrypted and signed before being published in a
   distributed key-value storage (Section 6).  In this process, unique
   zone identification is hidden from the network through the use of key
   blinding.  Key blinding allows the creation of signatures for zone
   contents using a blinded public/private key pair.  This blinding is
   realized using a deterministic key derivation from the original zone
   key and corresponding private key using record label values as
   blinding factors.  Specifically, the zone owner can derive blinded
   private keys for each record set published under a label, and a
   resolver can derive the corresponding blinded public keys.  It is
   expected that GNS implementations use distributed or decentralized
   storages such as distributed hash tables (DHT) in order to facilitate
   availability within a network without the need for dedicated
   infrastructure.  Specification of such a distributed or decentralized
   storage is out of scope of this document, but possible existing
   implementations include those based on [RFC7363], [Kademlia] or
   [R5N].

   Names in GNS are domain names as defined in [RFC8499].  Starting from
   a configurable start zone, names are resolved by following zone
   delegations.  For each label in a name, the recursive GNS resolver
   fetches the respective record from the storage layer (Section 7).
   Without knowledge of the label values and the zone keys, the
   different derived keys are unlinkable both to the original zone key
   and to each other.  This prevents zone enumeration (except via
   impractical online brute force attacks) and requires knowledge of
   both the zone key and the label to confirm affiliation of a query or
   the corresponding encrypted record set with a specific zone.  At the
   same time, the blinded zone key provides resolvers with the ability
   to verify the integrity of the published information without
   disclosing the originating zone.

   In the remainder of this document, the "implementer" refers to the
   developer building a GNS implementation including, for example, zone
   management tools and name resolution components.

4.  Zones

   A zone in GNS is uniquely identified by its zone type and zone key.
   Each zone can be represented by a Zone Top-Level Domain (zTLD)
   string.

   A implementation SHOULD enable the user to create and manage zones.
   If this functionality is not implemented, names can still be resolved
   if zone keys for the initial step in the name resolution are
   available (see Section 7).

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   Each zone type (ztype) is assigned a unique 32-bit number when it is
   registered in the GNUnet Assigned Numbers Authority [GANA].  The
   ztype determines which cryptosystem is used for the asymmetric and
   symmetric key operations of the zone.  The ztype number always
   corresponds to a resource record type number identifying a delegation
   into a zone of this type.  To ensure that there are no conflicts with
   DNS record types, ztypes are always assigned numeric values above
   65535.

   For any zone, let d be the private key and zk the public zone key.
   The specific wire format used depends on the ztype.  The creation of
   zone keys for the default ztypes are specified in Section 5.1.  New
   ztypes may be specified in the future, for example if the
   cryptographic mechanisms used in this document are broken.  Any ztype
   MUST define the following set of cryptographic functions:

   KeyGen() -> d, zk  is a function to generate a new private key d and
      the corresponding public zone key zk.

   ZKDF-Private(d,label) -> d'  is a zone key derivation function which
      blinds a private key d using label, resulting in another private
      key which can be used to create cryptographic signatures.  We note
      that GNS only requires a signature to be created directly with d
      to sign a revocation message for the zone key zk.

   ZKDF-Public(zk,label) -> zk'  is a zone key derivation function which
      blinds a zone key zk using a label. zk and zk' must be unlinkable.
      Furthermore, blinding zk with different values for the label must
      result in different, unlinkable zk' values.

   S-Encrypt(zk,label,expiration,message) -> ciphertext  is a symmetric
      encryption function which encrypts the record data based on key
      material derived from the zone key, a label, and an expiration
      timestamp.  In order to leverage performance-enhancing caching
      features of certain underlying storages, in particular DHTs, a
      deterministic encryption scheme is recommended.

   S-Decrypt(zk,label,expiration,ciphertext) -> message  is a symmetric
      decryption function which decrypts the encrypted record data based
      on key material derived from the zone key, a label, and an
      expiration timestamp.

   Sign(d,message) -> signature, SignDerived(d,label,message) ->
   signature  is a function to sign a message (typically encrypted

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      record data) using the (blinded) private key d (d'), yielding an
      unforgeable cryptographic signature.  In order to leverage
      performance-enhancing caching features of certain underlying
      storages, in particular DHTs, a deterministic signature scheme is
      recommended.

   Verify(zk,message,signature) -> boolean,
   VerifyDerived(zk,label,message,signature) -> boolean  is a function
      to verify the signature was created by the private key d (or
      derived key d') corresponding to the zone key zk (or derived zone
      key zk') where d,zk := Keygen().  If derivations were used, they
      must have used the same label.  The function returns a boolean
      value of "TRUE" if the signature is valid, and otherwise "FALSE".

4.1.  Zone Top-Level Domain

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |       ZONE TYPE       |      ZONE KEY         /
   +-----+-----+-----+-----+                       /
   /                                               /
   /                                               /

                                  Figure 1

   The decoded binary representation of the zTLD

   The zTLD is the Zone Top-Level Domain.  It is a string which encodes
   the zone type and zone key into a domain name.  The zTLD is used as a
   globally unique reference to a specific namespace in the process of
   name resolution.  To encode the zone key, a zone key label zkl is
   derived from a concatenation of the zone type and zone key (see
   Figure 1).  The result is encoded using a variation of the Crockford
   Base32 encoding [CrockfordB32] called Base32GNS.  The encoding and
   decoding symbols for Base32GNS including this modification are
   defined in Figure 23.  The functions for encoding and decoding based
   on this table are called Base32GNS-Encode and Base32GNS-Decode,
   respectively.

   For the string representation of a zTLD we define:

   zkl := Base32GNS-Encode(ztype||zkey)
   ztype||zkey := Base32GNS-Decode(zkl)

   If zkl is less than 63 characters, it can directly be used as a zTLD.
   If zkl is longer than 63 characters, the zTLD is constructed by
   dividing zkl into smaller labels separated by the label separator
   ".".  Here, the most significant bytes of the "ztype||zkey"

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   concatenation must be contained in the rightmost label of the
   resulting string and the least significant bytes in the leftmost
   label of the resulting string.  This allows the resolver to determine
   the ztype and zkl length from the rightmost label and to subsequently
   determine how many labels the zTLD should span.  For example,
   assuming a zkl of 130 characters, the encoding would be:

   zTLD := zkl[126..129].zkl[63..125].zkl[0..62]

4.2.  Zone Revocation

   Whenever a resolver encounters a new GNS zone, it MUST check against
   the local revocation list whether the respective zone key has been
   revoked.  If the zone key was revoked, the resolution MUST fail with
   an empty result set.

   In order to revoke a zone key, a signed revocation message MUST be
   published.  This message MUST be signed using the private key.  The
   revocation message is broadcast to the network.  The specification of
   the broadcast mechanism is out of scope for this document.  A
   possible broadcast mechanism for efficient flooding in a distributed
   network is implemented in [GNUnet].  Alternatively, revocation
   messages could also be distributed via a distributed ledger or a
   trusted central server.  To prevent flooding attacks, the revocation
   message MUST contain a proof of work (PoW).  The revocation message
   including the PoW MAY be calculated ahead of time to support timely
   revocation.

   For all occurrences below, "Argon2id" is the Password-based Key
   Derivation Function as defined in [RFC9106].  For the PoW
   calculations the algorithm is instantiated with the following
   parameters:

   S  The salt.  Fixed 16-byte string: "GnsRevocationPow".

   t  Number of iterations: 3

   m  Memory size in KiB: 1024

   T  Output length of hash in bytes: 64

   p  Parallelization parameter: 1

   v  Algorithm version: 0x13

   y  Algorithm type (Argon2id): 2

   X  Unused

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   K  Unused

   Figure 2 illustrates the format of the data "P" on which the PoW is
   calculated.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                      POW                      |
   +-----------------------------------------------+
   |                   TIMESTAMP                   |
   +-----------------------------------------------+
   |       ZONE TYPE       |    ZONE KEY           |
   +-----+-----+-----+-----+                       |
   /                                               /
   /                                               /
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                  Figure 2

   The Format of the PoW Data.

   POW  A 64-bit value that is a solution to the PoW.  In network byte
      order.

   TIMESTAMP  denotes the absolute 64-bit date when the revocation was
      computed.  In microseconds since midnight (0 hour), January 1,
      1970 UTC in network byte order.

   ZONE TYPE  is the 32-bit zone type.

   ZONE KEY  is the 256-bit public key zk of the zone which is being
      revoked.  The wire format of this value is defined by the ZONE
      TYPE.

   Traditionally, PoW schemes require to find a POW value such that at
   least D leading zeroes are found in the hash result.  D is then
   referred to as the difficulty of the PoW.  In order to reduce the
   variance in time it takes to calculate the PoW, we require that a
   number Z different PoWs must be found that on average have D leading
   zeroes.

   The resulting proofs may then published and disseminated.  The
   concrete dissemination and publication methods are out of scope of
   this document.  Given an average difficulty of D, the proofs have an
   expiration time of EPOCH.  With each additional bit difficulty, the
   lifetime of the proof is prolonged for another EPOCH.  Consequently,
   by calculating a more difficult PoW, the lifetime of the proof can be
   increased on demand by the zone owner.

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   The parameters are defined as follows:

   Z  The number of PoWs required is fixed at 32.

   D  The minimum average difficulty is fixed at 22.

   EPOCH  A single epoch is fixed at 365 days.

   The revocation message wire format is illustrated in Figure 3.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   TIMESTAMP                   |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                      TTL                      |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                     POW_0                     |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                       ...                     |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                     POW_Z-1                   |
   +-----------------------------------------------+
   |       ZONE TYPE       |    ZONE KEY           |
   +-----+-----+-----+-----+                       |
   /                                               /
   /                                               /
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   SIGNATURE                   |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                  Figure 3

   The Revocation Message Wire Format.

   TIMESTAMP  denotes the absolute 64-bit date when the revocation was
      computed.  In microseconds since midnight (0 hour), January 1,
      1970 UTC in network byte order.  This is the same value as the
      time stamp used in the individual PoW calculations.

   TTL  denotes the relative 64-bit time to live of the record in

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      microseconds also in network byte order.  This field is
      informational for a verifier.  A verifier MAY discard a revocation
      without checking the POW values or the signature if the TTL (in
      combination with TIMESTAMP) indicates that the revocation has
      already expired.  However, the actual TTL of the revocation must
      be determined by examining the leading zeroes in the proof of work
      calculation.

   POW_i  The values calculated as part of the PoW, in network byte
      order.  Each POW_i MUST be unique in the set of POW values.  To
      facilitate fast verification of uniqueness, the POW values must be
      given in strictly monotonically increasing order in the message.

   ZONE TYPE  The 32-bit zone type corresponding to the zone key.

   ZONE KEY  is the public key zk of the zone which is being revoked and
      the key to be used to verify SIGNATURE.

   SIGNATURE  A signature over a time stamp and the zone zk of the zone
      which is revoked and corresponds to the key used in the PoW.  The
      signature is created using the Sign() function of the cryptosystem
      of the zone and the private key (see Section 4).

   The signature over the public key covers a 32-bit header prefixed to
   the time stamp and public key fields.  The header includes the key
   length and signature purpose.  The wire format is illustrated in
   Figure 4.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |         SIZE          |       PURPOSE (0x03)  |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   TIMESTAMP                   |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |       ZONE TYPE       |     ZONE KEY          |
   +-----+-----+-----+-----+                       |
   /                                               /
   /                                               /
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                  Figure 4

   The Wire Format of the Revocation Data for Signing.

   SIZE  A 32-bit value containing the length of the signed data in
      bytes in network byte order.

   PURPOSE  A 32-bit signature purpose flag.  The value of this field

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      MUST be 3.  The value is encoded in network byte order.  It
      defines the context in which the signature is created so that it
      cannot be reused in other parts of the protocol including possible
      future extensions.  The value of this field corresponds to an
      entry in the GANA "GNUnet Signature Purpose" registry Section 10.

   TIMESTAMP  Field as defined in the revocation message above.

   ZONE TYPE  Field as defined in the revocation message above.

   ZONE KEY  Field as defined in the revocation message above.

   In order to verify a revocation the following steps MUST be taken:

   1.  The signature MUST be verified against the zone key.

   2.  The set of POW values MUST NOT contain duplicates which MUST be
       checked by verifying that the values are strictly monotonically
       increasing.

   3.  The average number of leading zeroes D' resulting from the
       provided POW values MUST be greater than and not equal to D.
       Implementers MUST NOT use an integer data type to calculate or
       represent D'.

   4.  The validation period (TTL) of the revocation is calculated as
       (D'-D) * EPOCH * 1.1.  The EPOCH is extended by 10% in order to
       deal with unsynchronized clocks.  The TTL added on top of the
       TIMESTAMP yields the expiration date.  Should the verifier
       calculate the TTL and find that it differs from the field value,
       the verifier MUST continue and use the calculated value when
       forwarding the revocation.

   5.  The current time SHOULD be between TIMESTAMP and TIMESTAMP+TTL.
       Implementations MAY process the revocation without validating
       this.

5.  Resource Records

   A GNS implementer SHOULD provide a mechanism to create and manage
   resource records for local zones.  A new local zone is established by
   selecting a zone type and creating a zone key pair.  As records may
   be added to each zone by its owner, a (local) persistence mechanism
   such as a database for resource records and zones SHOULD be provided.
   This local zone database is used by the name resolution logic and
   serves as a basis for publishing zones into the GNS storage (see
   Section 6).

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   A GNS resource record holds the data of a specific record in a zone.
   The resource record format is defined in Figure 5.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   EXPIRATION                  |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |    SIZE   |   FLAGS   |          TYPE         |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                      DATA                     /
   /                                               /
   /                                               /

                                  Figure 5

   The Resource Record Wire Format.

   EXPIRATION  denotes the absolute 64-bit expiration date of the
      record.  In microseconds since midnight (0 hour), January 1, 1970
      UTC in network byte order.

   SIZE  denotes the 16-bit size of the DATA field in bytes and in
      network byte order.

   FLAGS  is a 16-bit resource record flags field (see below).

   TYPE  is the 32-bit resource record type.  This type can be one of
      the GNS resource records as defined in Section 5 or a DNS record
      type as defined in [RFC1035] or any of the complementary
      standardized DNS resource record types.  This value must be stored
      in network byte order.  Note that values below 2^16 are reserved
      for allocation via IANA [RFC6895], while values above 2^16 are
      allocated by the GNUnet Assigned Numbers Authority [GANA].

   DATA  the variable-length resource record data payload.  The content
      is defined by the respective type of the resource record.

   Flags indicate metadata surrounding the resource record.  A flag
   value of 0 indicates that all flags are unset.  Applications creating
   resource records MUST set all bits which are not defined as a flag to
   0.  Additional flags may be defined in future protocol versions.  If
   an application or implementation encounters a flag which it does not
   recognize, it MUST be ignored.  Figure 6 illustrates the flag
   distribution in the 16-bit flag field of a resource record:

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    0        1        2        3        4        5...
   +--------+--------+--------+--------+--------+----
   |CRITICAL|SHADOW  |SUPPL   |RESERVED
   +--------+--------+--------+--------+--------+----

                                  Figure 6

   The Resource Record Flag Wire Format.

   CRITICAL  If this flag is set, it indicates that processing is
      critical.  Implementations that do not support the record type or
      are otherwise unable to process the record must abort resolution
      upon encountering the record in the resolution process.

   SHADOW  If this flag is set, this record should be ignored by
      resolvers unless all (other) records of the same record type have
      expired.  Used to allow zone publishers to facilitate good
      performance when records change by allowing them to put future
      values of records into the storage.  This way, future values can
      propagate and may be cached before the transition becomes active.

   SUPPL  This is a supplemental record.  It is provided in addition to
      the other records.  This flag indicates that this record is not
      explicitly managed alongside the other records under the
      respective name but may be useful for the application.  This flag
      should only be encountered by a resolver for records obtained from
      the storage.

5.1.  Zone Delegation Records

   This section defines the initial set of zone delegation record types.
   Any implementation SHOULD support all zone types defined here and MAY
   support any number of additional delegation records defined in the
   GNU Name System Record Types registry (see Section 10).  Zone
   delegation records MUST have the CRTITICAL flag set.  Not supporting
   some zone types MAY result in resolution failures.  This MAY BE a
   valid choice if some zone delegation record types have been
   determined to be cryptographically insecure.  Zone delegation records
   MUST NOT be stored and published under the apex label.  A zone
   delegation record type value is the same as the respective ztype
   value.  The ztype defines the cryptographic primitives for the zone
   that is being delegated to.  A zone delegation resource record
   payload contains the public key of the zone to delegate to.  A zone
   delegation record MUST be the only record under a label.  No other
   records are allowed.

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5.1.1.  PKEY

   In GNS, a delegation of a label to a zone of type "PKEY" is
   represented through a PKEY record.  The PKEY DATA entry wire format
   can be found in Figure 7.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   PUBLIC KEY                  |
   |                                               |
   |                                               |
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                  Figure 7

   The PKEY Wire Format.

   PUBLIC KEY  A 256-bit Ed25519 public key.

   For PKEY zones the zone key material is derived using the curve
   parameters of the twisted Edwards representation of Curve25519
   [RFC7748] (a.k.a.  Ed25519) with the ECDSA scheme [RFC6979].
   Consequently, we use the following naming convention for our
   cryptographic primitives for PKEY zones:

   d  is a 256-bit Ed25519 private key (private scalar).

   zk  is the Ed25519 public zone key corresponding to d.

   p  is the prime of edwards25519 as defined in [RFC7748], i.e.  2^255
      - 19.

   G  is the group generator (X(P),Y(P)) of edwards25519 as defined in
      [RFC7748].

   L  is the order of the prime-order subgroup of edwards25519 in
      [RFC7748].

   KeyGen()  The generation of the private scalar d and the curve point
      zk := d*G (where G is the group generator of the elliptic curve)
      as defined in Section 2.2. of [RFC6979] represents the KeyGen()
      function.

   The zone type and zone key of a PKEY are 4 + 32 bytes in length.
   This means that a zTLD will always fit into a single label and does
   not need any further conversion.

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   Given a label, the output d' of the ZKDF-Private(d,label) function
   for zone key blinding is calculated as follows for PKEY zones:

   ZKDF-Private(d,label):
     zk := d * G
     PRK_h := HKDF-Extract ("key-derivation", zk)
     h := HKDF-Expand (PRK_h, label || "gns", 512 / 8)
     d' := (h * d) mod L
     return d'

   Equally, given a label, the output zk' of the ZKDF-Public(zk,label)
   function is calculated as follows for PKEY zones:

   ZKDF-Public(zk,label)
     PRK_h := HKDF-Extract ("key-derivation", zk)
     h := HKDF-Expand (PRK_h, label || "gns", 512 / 8)
     zk' := (h mod L) * zk
     return zk'

   The PKEY cryptosystem uses a hash-based key derivation function
   (HKDF) as defined in [RFC5869], using SHA-512 [RFC6234] for the
   extraction phase and SHA-256 [RFC6234] for the expansion phase.
   PRK_h is key material retrieved using an HKDF using the string "key-
   derivation" as salt and the zone key as initial keying material.  h
   is the 512-bit HKDF expansion result and must be interpreted in
   network byte order.  The expansion information input is a
   concatenation of the label and the string "gns".  The label is a
   UTF-8 string under which the resource records are published.  The
   multiplication of zk with h is a point multiplication, while the
   multiplication of d with h is a scalar multiplication.

   The Sign() and Verify() functions for PKEY zones are implemented
   using 512-bit ECDSA deterministic signatures as specified in
   [RFC6979].  The same functions can be used for derived keys:

   SignDerived(d,label,message):
     d' := ZKDF-Private(d,label)
     return Sign(d',message)

   A signature (R,S) is valid if the following holds:

   VerifyDerived(zk,label,message,signature):
     zk' := ZKDF-Public(zk,label)
     return Verify(zk',message,signature)

   The S-Encrypt() and S-Decrypt() functions use AES in counter mode as
   defined in [MODES] (CTR-AES-256):

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   S-Encrypt(zk,label,expiration,plaintext):
     PRK_k := HKDF-Extract ("gns-aes-ctx-key", zk)
     PRK_n := HKDF-Extract ("gns-aes-ctx-iv", zk)
     K := HKDF-Expand (PRK_k, label, 256 / 8)
     NONCE := HKDF-Expand (PRK_n, label, 32 / 8)
     IV := NONCE || expiration || 0x0000000000000001
     return CTR-AES256(K, IV, plaintext)

                                  Figure 8

   The PKEY S-Encrypt Procedure.

   S-Decrypt(zk,label,expiration,ciphertext):
     PRK_k := HKDF-Extract ("gns-aes-ctx-key", zk)
     PRK_n := HKDF-Extract ("gns-aes-ctx-iv", zk)
     K := HKDF-Expand (PRK_k, label, 256 / 8)
     NONCE := HKDF-Expand (PRK_n, label, 32 / 8)
     IV := NONCE || expiration || 0x0000000000000001
     return CTR-AES256(K, IV, ciphertext)

                                  Figure 9

   The PKEY S-Decrypt Procedure.

   The key K and counter IV are derived from the record label and the
   zone key zk using a hash-based key derivation function (HDKF) as
   defined in [RFC5869].  SHA-512 [RFC6234] is used for the extraction
   phase and SHA-256 [RFC6234] for the expansion phase.  The output
   keying material is 32 bytes (256 bits) for the symmetric key and 4
   bytes (32 bits) for the nonce.  The symmetric key K is a 256-bit AES
   [RFC3826] key.

   The nonce is combined with a 64-bit initialization vector and a
   32-bit block counter as defined in [RFC3686].  The block counter
   begins with the value of 1, and it is incremented to generate
   subsequent portions of the key stream.  The block counter is a 32-bit
   integer value in network byte order.  The initialization vector is
   the expiration time of the resource record block in network byte
   order.  The resulting counter (IV) wire format can be found in
   Figure 10.

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   0     8     16    24    32
   +-----+-----+-----+-----+
   |         NONCE         |
   +-----+-----+-----+-----+
   |       EXPIRATION      |
   |                       |
   +-----+-----+-----+-----+
   |      BLOCK COUNTER    |
   +-----+-----+-----+-----+

                                 Figure 10

   The Block Counter Wire Format.

5.1.2.  EDKEY

   In GNS, a delegation of a label to a zone of type "EDKEY" is
   represented through a EDKEY record.  The EDKEY DATA entry wire format
   is illustrated in Figure 11.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   PUBLIC KEY                  |
   |                                               |
   |                                               |
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 11

   The EDKEY DATA Wire Format.

   PUBLIC KEY  A 256-bit EdDSA zone key.

   For EDKEY zones the zone key material is derived using the curve
   parameters of the twisted edwards representation of Curve25519
   [RFC7748] (a.k.a.  Ed25519) with the Ed25519 scheme [ed25519] as
   specified in [RFC8032].  Consequently, we use the following naming
   convention for our cryptographic primitives for EDKEY zones:

   d  is a 256-bit EdDSA private key.

   a  is is an integer derived from d using the SHA-512 hash function as
      defined in [RFC8032].

   zk  is the EdDSA public key corresponding to d.  It is defined as the
      curve point a*G where G is the group generator of the elliptic
      curve as defined in [RFC8032].

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   p  is the prime of edwards25519 as defined in [RFC8032], i.e.  2^255
      - 19.

   G  is the group generator (X(P),Y(P)) of edwards25519 as defined in
      [RFC8032].

   L  is the order of the prime-order subgroup of edwards25519 in
      [RFC8032].

   KeyGen()  The generation of the private key d and the associated
      public key zk := a*G where G is the group generator of the
      elliptic curve and a is an integer derived from d using the
      SHA-512 hash function as defined in Section 5.1.5 of [RFC8032]
      represents the KeyGen() function.

   The zone type and zone key of an EDKEY are 4 + 32 bytes in length.
   This means that a zTLD will always fit into a single label and does
   not need any further conversion.

   The "EDKEY" ZKDF instantiation is based on [Tor224].  The calculation
   of a is defined in Section 5.1.5 of [RFC8032].  Given a label, the
   output of the ZKDF-Private function for zone key blinding is
   calculated as follows for EDKEY zones:

   ZKDF-Private(d,label):
     /* EdDSA clamping */
     a := SHA-512 (d)
     a[0] &= 248
     a[31] &= 127
     a[31] |= 64
     /* Calculate zk from d */
     zk := a * G

     /* Calculate the blinding factor */
     PRK_h := HKDF-Extract ("key-derivation", zk)
     h := HKDF-Expand (PRK_h, label || "gns", 512 / 8)
     /* Ensure that h == h mod L */
     h[31] &= 7

     a1 := a >> 3
     a2 := (h * a1) mod L
     d' := a2 << 3
     return d'

   Equally, given a label, the output of the ZKDF-Public function is
   calculated as follows for PKEY zones:

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   ZKDF-Public(zk,label):
     /* Calculate the blinding factor */
     PRK_h := HKDF-Extract ("key-derivation", zk)
     h := HKDF-Expand (PRK_h, label || "gns", 512 / 8)
     /* Ensure that h == h mod L */
     h[31] &= 7

     zk' := h * zk
     return zk'

   We note that implementers SHOULD employ a constant time scalar
   multiplication for the constructions above to protect against timing
   attacks.  Otherwise, timing attacks may leak private key material if
   an attacker can predict when a system starts the publication process.

   The EDKEY cryptosystem uses a hash-based key derivation function
   (HKDF) as defined in [RFC5869], using SHA-512 [RFC6234] for the
   extraction phase and HMAC-SHA256 [RFC6234] for the expansion phase.
   PRK_h is key material retrieved using an HKDF using the string "key-
   derivation" as salt and the zone key as initial keying material.  The
   blinding factor h is the 512-bit HKDF expansion result.  The
   expansion information input is a concatenation of the label and the
   string "gns".  The result of the HKDF must be clamped and interpreted
   in network byte order.  a is the 256-bit integer corresponding to the
   256-bit private key d.  The label is a UTF-8 string under which the
   resource records are published.  The multiplication of zk with h is a
   point multiplication, while the division and multiplication of a and
   a1 with the co-factor are integer operations.

   The Sign(d,message) and Verify(zk,message,signature) procedures MUST
   be implemented as defined in [RFC8032].

   Signatures for EDKEY zones using the derived private scalar d' are
   not compliant with [RFC8032].  As the corresponding private key to
   the derived private scalar d' is not known, it is not possible to
   deterministically derive the signature part R according to [RFC8032].
   Instead, signatures MUST be generated as follows for any given
   message and private zone key: A nonce is calculated from the highest
   32 bytes of the expansion of the private key d and the blinding
   factor h.  The nonce is then hashed with the message to r.  This way,
   we include the full derivation path in the calculation of the R value
   of the signature, ensuring that it is never reused for two different
   derivation paths or messages.

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   SignDerived(d,label,message):
     /* EdDSA clamping */
     a := SHA-512 (d)
     a[0] &= 248
     a[31] &= 127
     a[31] |= 64
     /* Calculate zk from d */
     zk := a * G

     /* Calculate blinding factor */
     PRK_h := HKDF-Extract ("key-derivation", zk)
     h := HKDF-Expand (PRK_h, label || "gns", 512 / 8)

     d' := ZKDF-Private(d,label)
     dh := SHA-512 (d)
     nonce := SHA-256 (dh[32..63] || h)
     r := SHA-512 (nonce || message)
     R := r * G
     S := r + SHA-512(R || zk' || message) * d' mod L
     return (R,S)

   A signature (R,S) is valid if the following holds:

   VerifyDerived(zk,label,message,signature):
     zk' := ZKDF-Public(zk,label)
     (R,S) := signature
     return S * G == R + SHA-512(R, zk', message) * zk'

   The S-Encrypt() and S-Decrypt() functions use XSalsa20 as defined in
   [XSalsa20] (XSalsa20-Poly1305):

   S-Encrypt(zk,label,expiration,message):
     PRK_k := HKDF-Extract ("gns-xsalsa-ctx-key", zk)
     PRK_n := HKDF-Extract ("gns-xsalsa-ctx-iv", zk)
     K := HKDF-Expand (PRK_k, label, 256 / 8)
     NONCE := HKDF-Expand (PRK_n, label, 128 / 8)
     IV := NONCE || expiration
     return XSalsa20-Poly1305(K, IV, message)

   S-Decrypt(zk,label,expiration,ciphertext):
     PRK_k := HKDF-Extract ("gns-xsalsa-ctx-key", zk)
     PRK_n := HKDF-Extract ("gns-xsalsa-ctx-iv", zk)
     K := HKDF-Expand (PRK_k, label, 256 / 8)
     NONCE := HKDF-Expand (PRK_n, label, 128 / 8)
     IV := NONCE || expiration
     return XSalsa20-Poly1305(K, IV, ciphertext)

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   The result of the XSalsa20-Poly1305 encryption function is the
   encrypted ciphertext followed by the 128-bit authentication tag.
   Accordingly, the length of encrypted data equals the length of the
   data plus the 16 bytes of the authentication tag.

   The key K and counter IV are derived from the record label and the
   zone key zk using a hash-based key derivation function (HKDF) as
   defined in [RFC5869].  SHA-512 [RFC6234] is used for the extraction
   phase and SHA-256 [RFC6234] for the expansion phase.  The output
   keying material is 32 bytes (256 bits) for the symmetric key and 16
   bytes (128 bits) for the NONCE.  The symmetric key K is a 256-bit
   XSalsa20 [XSalsa20] key.  No additional authenticated data (AAD) is
   used.

   The nonce is combined with an 8 byte initialization vector.  The
   initialization vector is the expiration time of the resource record
   block in network byte order.  The resulting counter (IV) wire format
   is illustrated in Figure 12.

   0     8     16    24    32
   +-----+-----+-----+-----+
   |         NONCE         |
   |                       |
   |                       |
   |                       |
   +-----+-----+-----+-----+
   |       EXPIRATION      |
   |                       |
   +-----+-----+-----+-----+

                                 Figure 12

   The Counter Block Initialization Vector

5.2.  Redirection Records

   Redirect records may be used to redirect resolution.  Any
   implementation SHOULD support all redirection record types defined
   here and MAY support any number of additional redirection records
   defined in the GNU Name System Record Types registry (see
   Section Section 10).  Redirection records MUST have the CRTITICAL
   flag set.  Not supporting some record types MAY result in resolution
   failures.  This MAY BE a valid choice if some redirection record
   types have been determined to be insecure, or if an application has
   reasons to not support redirection to DNS for reasons such as
   complexity or security.  Redirection records MUST NOT be stored and
   published under the apex label.

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5.2.1.  REDIRECT

   A REDIRECT record is the GNS equivalent of a CNAME record in DNS.  A
   REDIRECT record MUST be the only record under a label.  No other
   records are allowed.  Details on processing of this record is defined
   in Section 7.3.1.  A REDIRECT DATA entry is illustrated in Figure 13.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   REDIRECT NAME               |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 13

   The REDIRECT DATA Wire Format

   REDIRECT NAME  The name to continue with.  The value of a redirect
      record may be a regular name, or a relative name.  Relative GNS
      names are indicated using the suffix ".+".  The string is UTF-8
      encoded and 0-terminated.

5.2.2.  GNS2DNS

   It is possible to delegate a label back into DNS through a GNS2DNS
   record.  The resource record contains a DNS name for the resolver to
   continue with in DNS followed by a DNS server.  Both names are in the
   format defined in [RFC1034] for DNS names.  There MAY be multiple
   GNS2DNS records under a label.  There MAY also be DNSSEC DS records
   or any other records used to secure the connection with the DNS
   servers under the same label.  No other record types are allowed in
   the same record set.  A GNS2DNS DATA entry is illustrated in
   Figure 14.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                    DNS NAME                   |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                 DNS SERVER NAME               |
   /                                               /
   /                                               /
   |                                               |
   +-----------------------------------------------+

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                                 Figure 14

   The GNS2DNS DATA Wire Format

   DNS NAME  The name to continue with in DNS.  The value is UTF-8
      encoded and 0-terminated.

   DNS SERVER NAME  The DNS server to use.  May be an IPv4 address in
      dotted-decimal form or an IPv6 address in colon-hexadecimal form
      or a DNS name.  It may also be a relative GNS name ending with a
      "+" as the rightmost label.  The implementation MUST check the
      string syntactically for an IP address in the respective notation
      before checking for a relative GNS name.  If all three checks
      fail, the name MUST be treated as a DNS name.  The value is UTF-8
      encoded and 0-terminated.

   NOTE: If an application uses DNS names obtained from GNS2DNS records
   in a DNS request they must first be converted to an IDNA punycode
   representation [RFC5891].

5.3.  Auxiliary Records

   This section defines the initial set of auxiliary GNS record types.
   Any implementation SHOULD be able to process the specified record
   types according to Section 7.3.

5.3.1.  LEHO

   Applications can use the GNS to lookup IPv4 or IPv6 addresses of
   internet services.  However, sometimes connecting to such services
   does not only require the knowledge of an address and port, but also
   requires the canonical DNS name of the service to be transmitted over
   the transport protocol.  In GNS, legacy host name records provide
   applications the DNS name that is required to establish a connection
   to such a service.  The most common use case is HTTP virtual hosting,
   where a DNS name must be supplied in the HTTP "Host"-header.  Using a
   GNS name for the "Host"-header may not work as it may not be globally
   unique.  Furthermore, even if uniqueness is not an issue, the legacy
   service might not even be aware of GNS.  A LEHO resource record is
   expected to be found together in a single resource record with an
   IPv4 or IPv6 address.  A LEHO DATA entry is illustrated in Figure 15.

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   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                 LEGACY HOSTNAME               |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 15

   The LEHO DATA Wire Format.

   LEGACY HOSTNAME  A UTF-8 string (which is not 0-terminated)
      representing the legacy hostname.

   NOTE: If an application uses a LEHO value in an HTTP request header
   (e.g.  "Host:" header) it must be converted to an IDNA punycode
   representation [RFC5891].

5.3.2.  NICK

   Nickname records can be used by zone administrators to publish an the
   label that a zone prefers to have used when it is referred to.  This
   is a suggestion to other zones what label to use when creating a
   delegation record (Section 5.1) containing this zone key.  This
   record SHOULD only be stored under the apex label "@" but MAY be
   returned with record sets under any label as a supplemental record.
   Section 7.3.5 details how a resolver must process supplemental and
   non-supplemental NICK records.  A NICK DATA entry is illustrated in
   Figure 16.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                  NICKNAME                     |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 16

   The NICK DATA Wire Format.

   NICKNAME  A UTF-8 string (which is not 0-terminated) representing the
      preferred label of the zone.  This string MUST NOT include a "."
      character.

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5.3.3.  BOX

   In GNS, with the notable exception of zTLDs, every "." in a name
   delegates to another zone.  Furthermore, GNS lookups are expected to
   return all of the required useful information in one record set.
   This avoids unnecessary additional lookups and cryptographically ties
   together information that belongs together, making it impossible for
   an adversarial storage to provide partial answers that might omit
   information critical for security.

   However, this general strategy is incompatible with the special
   labels used by DNS for SRV and TLSA records.  Thus, GNS defines the
   BOX record format to box up SRV and TLSA records and include them in
   the record set of the label they are associated with.  For example, a
   TLSA record for "_https._tcp.example.org" will be stored in the
   record set of "example.org" as a BOX record with service (SVC) 443
   (https) and protocol (PROTO) 6 (tcp) and record TYPE "TLSA".  For
   reference, see also [RFC2782].  A BOX DATA entry is illustrated in
   Figure 17.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |   PROTO   |    SVC    |       TYPE            |
   +-----------+-----------------------------------+
   |                 RECORD DATA                   |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 17

   The BOX DATA Wire Format.

   PROTO  the 16-bit protocol number, e.g. 6 for tcp.  Note that values
      below 2^8 are reserved for allocation via IANA [RFC5237], while
      values above 2^8 are allocated by the GNUnet Assigned Numbers
      Authority [GANA].  In network byte order.

   SVC  the 16-bit service value of the boxed record.  In case of TCP
      and UDP it is the port number.  In network byte order.

   TYPE  is the 32-bit record type of the boxed record.  In network byte
      order.

   RECORD DATA  is a variable length field containing the "DATA" format
      of TYPE as defined for the respective TYPE in DNS.

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6.  Record Storage

   Any API which allows storing a value under a 512-bit key and
   retrieving one or more values from the key can be used by an
   implementation for record storage.  To be useful, the API MUST permit
   storing at least 176 byte values to be able to support the defined
   zone delegation record encodings, and SHOULD allow at least 1024 byte
   values.  We assume that an implementation realizes two procedures on
   top of a storage:

   PUT(key,value)
   GET(key) -> value

   There is no explicit delete function as the deletion of a non-expired
   record would require a revocation of the record.  In GNS, zones can
   only be revoked as a whole.  Records automatically expire and it is
   under the discretion of the storage as to when to delete the record.
   The GNS implementation MUST NOT publish expired resource records.
   Any GNS resolver MUST discard expired records returned from the
   storage.

   Resource records are grouped by their respective labels, encrypted
   and published together in a single resource records block (RRBLOCK)
   in the storage under a key q: PUT(q, RRBLOCK).  The key q is derived
   from the zone key and the respective label of the contained records.
   The required knowledge of both zone key and label in combination with
   the similarly derived symmetric secret keys and blinded zone keys
   ensure query privacy (see [RFC8324], Section 3.5).  The storage key
   derivation and records block creation is specified in the following
   sections.  The implementation MUST use the PUT storage procedure in
   order to update the zone contents accordingly.

6.1.  The Storage Key

   Given a label, the storage key q is derived as follows:

   q := SHA-512 (ZKDF-Public(zk, label))

   label  is a UTF-8 string under which the resource records are
      published.

   zk  is the zone key.

   q  Is the 512-bit storage key under which the resource records block
      is published.  It is the SHA-512 hash [RFC6234] over the derived
      zone key.

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6.2.  The Records Block

   GNS records are grouped by their labels and published as a single
   block in the storage.  The grouped record sets MAY be paired with any
   number of supplemental records.  Supplemental records MUST have the
   supplemental flag set (See Section 5).  The contained resource
   records are encrypted using a symmetric encryption scheme.  A GNS
   implementation publish RRBLOCKs in accordance to the properties and
   recommendations of the underlying storage.  This may include a
   periodic refresh operation to ensure the availability of the
   published RRBLOCKs.  The GNS RRBLOCK wire format is illustrated in
   Figure 18.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |          SIZE         |    ZONE TYPE          |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   /                  ZONE KEY                     /
   /                  (BLINDED)                    /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   SIGNATURE                   |
   /                                               /
   /                                               /
   |                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   EXPIRATION                  |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                    BDATA                      /
   /                                               /
   /                                               |
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 18

   The RRBLOCK Wire Format.

   SIZE  A 32-bit value containing the length of the block.  While a
      32-bit value is used, implementations MAY refuse to publish blocks
      beyond a certain size significantly below 4 GB.

   ZONE TYPE  is the 32-bit ztype.

   ZONE KEY  is the blinded zone key "ZKDF-Public(zk, label)" to be used
      to verify SIGNATURE.  The length and format of the public key
      depends on the ztype.

   SIGNATURE  The signature is computed over the EXPIRATION and BDATA

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      fields as detailed in Figure 19.  The length and format of the
      signature depends on the ztype.  The signature is created using
      the Sign() function of the cryptosystem of the zone and the
      derived private key "ZKDF-Private(d, label)" (see Section 4).

   EXPIRATION  Specifies when the RRBLOCK expires and the encrypted
      block SHOULD be removed from the storage and caches as it is
      likely stale.  However, applications MAY continue to use non-
      expired individual records until they expire.  The value MUST be
      set to the expiration time of the resource record contained within
      this block with the smallest expiration time.  If a records block
      includes shadow records, then the maximum expiration time of all
      shadow records with matching type and the expiration times of the
      non-shadow records is considered.  This is a 64-bit absolute date
      in microseconds since midnight (0 hour), January 1, 1970 UTC in
      network byte order.

   BDATA  The encrypted RDATA.  Its size is determined by the
      S-Encrypt() function of the ztype.

   The signature over the public key covers a 32-bit pseudo header
   conceptually prefixed to the EXPIRATION and the BDATA fields.  The
   wire format is illustrated in Figure 19.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |         SIZE          |       PURPOSE (0x0F)  |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   EXPIRATION                  |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                    BDATA                      |
   /                                               /
   /                                               /
   +-----+-----+-----+-----+-----+-----+-----+-----+

                                 Figure 19

   The Wire Format used for creating the signature of the RRBLOCK.

   SIZE  A 32-bit value containing the length of the signed data in
      bytes in network byte order.

   PURPOSE  A 32-bit signature purpose flag.  The value of this field
      MUST be 15.  The value is encoded in network byte order.  It
      defines the context in which the signature is created so that it
      cannot be reused in other parts of the protocol including possible
      future extensions.  The value of this field corresponds to an
      entry in the GANA "GNUnet Signature Purpose" registry Section 10.

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   EXPIRATION  Field as defined in the RRBLOCK message above.

   BDATA  Field as defined in the RRBLOCK message above.

   A symmetric encryption scheme is used to encrypt the resource records
   set RDATA into the BDATA field of a GNS RRBLOCK.  The wire format of
   the RDATA is illustrated in Figure 20.

   0     8     16    24    32    40    48    56
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                 EXPIRATION                    |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |    SIZE   |    FLAGS  |        TYPE           |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                      DATA                     /
   /                                               /
   /                                               /
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                   EXPIRATION                  |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |    SIZE   |    FLAGS  |        TYPE           |
   +-----+-----+-----+-----+-----+-----+-----+-----+
   |                     DATA                      /
   /                                               /
   +-----+-----+-----+-----+-----+-----+-----+-----+
   /                     PADDING                   /
   /                                               /

                                 Figure 20

   The RDATA Wire Format.

   EXPIRATION, SIZE, TYPE, FLAGS and DATA  These fields were defined in
      the resource record format in Section 5.

   PADDING  When publishing an RDATA block, the implementation MUST
      ensure that the size of the RDATA is a power of two using the
      padding field.  The field MUST be set to zero and MUST be ignored
      on receipt.  As a special exception, record sets with (only) a
      zone delegation record type are never padded.  Note that a record
      set with a delegation record MUST NOT contain other records.  If
      other records are encountered, the whole record block MUST be
      discarded.

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7.  Name Resolution

   Names in GNS are resolved by recursively querying the record storage.
   Recursive in this context means that a resolver does not provide
   intermediate results for a query.  Instead, it MUST respond to a
   resolution request with either the requested resource record or an
   error message in case the resolution fails.  In the following, we
   define how resolution is initiated and each iteration in the
   resolution is processed.

   GNS resolution of a name must start in a given starting zone
   indicated using a zone key.  Details on how the starting zone may be
   determined are discussed in Section 7.1.

   The application MAY provide a desired record type to the resolver.
   The desired record type is used to guide processing.  For example, if
   a zone delegation record type is requested, the resolution of the
   apex label in that zone must be skipped, as the desired record is
   already found.  The resolver implementation MUST NOT filter results
   according to the desired record type.  Filtering of record sets is
   typically done by the application.

7.1.  Start Zones

   The resolution of a GNS name starts in an initial start zone.  The
   resolver may have one or more local start zones configured which
   point to local or remote zone keys.  A resolver may also determine
   the start zone from the suffix of the name given for resolution, or
   using information retrieved out of band.

   The governance model of any zone is at the sole discretion of the
   zone owner.  However, the choice of start zone(s) is at the sole
   discretion of the local system administrator or user.  This property
   addresses the issue of a single hierarchy with a centrally controlled
   root and the related issue of distribution and management of root
   servers in DNS (see [RFC8324], Section 3.10 and 3.12).

   In the following, we give examples how a resolver SHOULD discover the
   start zone.  The process given is not exhaustive and resolvers MAY
   supplement it with other mechanisms or ignore it if the particular
   application requires a different process.

   GNS implementations MUST first try to interpret the top-level domain
   of a GNS name as a zone key representation (i.e. a zTLD).  If the
   top-level domain can be converted to a valid ztype and zone key
   value, the resulting zone key is used as the start zone:

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   Example name: www.example.<zTLD>
   => Start zone: zk of type ztype
   => Name to resolve from start zone: www.example

   In GNS, users MAY own and manage their own zones.  Each local zone
   SHOULD be associated with a single GNS label, but users MAY choose to
   use longer names consisting of multiple labels.  If the name of a
   locally managed zone matches the suffix of the name to be resolved,
   resolution MUST start from the respective local zone with the longest
   matching suffix:

   Example name: www.example.org
   Local zones:
   fr = (d0,zk0)
   org = (d1,zk1)
   com = (d2,zk2)
   ...
   => Start zone: zk1
   => Name to resolve from start zone: www.example

   Finally, additional "suffix-to-zone" mappings MAY be configured.
   Suffix to zone key mappings MUST be configurable through a local
   configuration file or database by the user or system administrator.
   The suffix MAY consist of multiple GNS labels concatenated with a
   ".".  If multiple suffixes match the name to resolve, the longest
   matching suffix MUST be used.  The suffix length of two results MUST
   NOT be equal.  This indicates a misconfiguration and the
   implementation MUST return an error.  If both a locally managed zone
   and a configuration entry exist for the same suffix, the locally
   managed zone MUST have priority.

   Example name: www.example.org
   Local suffix mappings:
   org = zk0
   example.org = zk1
   example.com = zk2
   ...
   => Start zone: zk1
   => Name to resolve from start zone: www

7.2.  Recursion

   In each step of the recursive name resolution, there is an
   authoritative zone zk and a name to resolve.  The name may be empty.
   Initially, the authoritative zone is the start zone.  If the name is
   empty, it is interpreted as the apex label "@".

   From here, the following steps are recursively executed, in order:

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   1.  Extract the right-most label from the name to look up.

   2.  Calculate q using the label and zk as defined in Section 6.1.

   3.  Perform a storage query GET(q) to retrieve the RRBLOCK.

   4.  Verify and process the RRBLOCK and decrypt the BDATA contained in
       it as defined by its zone type (see also Section 6.2).

   Upon receiving the RRBLOCK from the storage, as part of verifying the
   provided signature, the resolver MUST check that the SHA-512 hash of
   the derived authoritative zone key zk' from the RRBLOCK matches the
   query q and that the overall block is not yet expired.  If the
   signature does not match or the block is expired, the RRBLOCK MUST be
   ignored and, if applicable, the storage lookup GET(q) MUST continue
   to look for other RRBLOCKs.

7.3.  Record Processing

   Record processing occurs once a well-formed block was decrypted.  In
   record processing, only the valid records obtained are considered.
   To filter records by validity, the resolver MUST at least check the
   expiration time and the FLAGS of the respective record.  In
   particular, FLAGS may exclude shadow and supplemental records from
   being considered.  If the resolver encounters a record with the
   CRITICAL flag set and does not support the record type the resolution
   MUST be aborted and an error MUST be returned.  The information that
   the critical record could not be processed SHOULD be returned in the
   error description.  The implementation MAY choose not to return the
   reason for the failure, merely complicating troubleshooting for the
   user.  The next steps depend on the context of the name we are trying
   to resolve:

   *  Case 1: If the filtered record set consists of a single REDIRECT
      record, the remainder of the name is prepended to the REDIRECT
      data and the recursion is started again from the resulting name.
      Details are described in Section 7.3.1.

   *  Case 2: If the filtered record set consists exclusively of one or
      more GNS2DNS records resolution continues with DNS.  Details are
      described in Section 7.3.2.

   *  Case 3: If the remainder of the name to be resolved is of the
      format "_SERVICE._PROTO" and the record set contains one or more
      matching BOX records, the records in the BOX records are the final
      result and the recursion is concluded as described in
      Section 7.3.3.

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   *  Case 4: If the current record set consist of a single delegation
      record, resolution of the remainder of the name is delegated to
      the target zone as described in Section 7.3.4.

   *  Case 5: If the remainder of the name to resolve is empty the
      record set (including supplemental records) is the final result
      and the recursion is concluded.

   *  Otherwise, resolution fails and the resolver MUST return an empty
      record set.

7.3.1.  REDIRECT

   If the remaining name is empty and the desired record type is
   REDIRECT, in which case the resolution concludes with the REDIRECT
   record.  If the redirect name ends in ".+", resolution continues in
   GNS with the new name in the current zone.  Otherwise, the resulting
   name is resolved via the default operating system name resolution
   process.  This may in turn trigger a GNS name resolution process
   depending on the system configuration.  In case resolution continues
   in DNS, the name MUST first be converted to an IDNA punycode
   representation [RFC5891].

   In order to prevent infinite loops, the resolver MUST implement loop
   detections or limit the number of recursive resolution steps.  The
   loop detection MUST be effective even if a REDIRECT found in GNS
   triggers subsequent GNS lookups via the default operating system name
   resolution process.

7.3.2.  GNS2DNS

   When a resolver encounters one or more GNS2DNS records and the
   remaining name is empty and the desired record type is GNS2DNS, the
   GNS2DNS records are returned.

   Otherwise, it is expected that the resolver first resolves the IP
   addresses of the specified DNS name servers.  The DNS name may have
   to be converted to an IDNA punycode representation [RFC5891] for
   resolution in DNS.  GNS2DNS records MAY contain numeric IPv4 or IPv6
   addresses, allowing the resolver to skip this step.  The DNS server
   names may themselves be names in GNS or DNS.  If the DNS server name
   ends in ".+", the rest of the name is to be interpreted relative to
   the zone of the GNS2DNS record.  If the DNS server name ends in a
   label representation of a zone key, the DNS server name is to be
   resolved against the GNS zone zk.

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   Multiple GNS2DNS records may be stored under the same label, in which
   case the resolver MUST try all of them.  The resolver MAY try them in
   any order or even in parallel.  If multiple GNS2DNS records are
   present, the DNS name MUST be identical for all of them, if not the
   resolution fails and an appropriate error is SHOULD be returned to
   the application.

   If there are DNSSEC DS records or any other records used to secure
   the connection with the DNS servers stored under the label, the DNS
   resolver SHOULD use them to secure the connection with the DNS
   server.

   Once the IP addresses of the DNS servers have been determined, the
   DNS name from the GNS2DNS record is appended to the remainder of the
   name to be resolved, and resolved by querying the DNS name server(s).
   As the DNS servers specified are possibly authoritative DNS servers,
   the GNS resolver MUST support recursive DNS resolution and MUST NOT
   delegate this to the authoritative DNS servers.  The first successful
   recursive name resolution result is returned to the application.  In
   addition, the resolver SHOULD return the queried DNS name as a
   supplemental LEHO record (see Section 5.3.1) with a relative
   expiration time of one hour.

   Once the transition from GNS into DNS is made through a GNS2DNS
   record, there is no "going back".  The (possibly recursive)
   resolution of the DNS name MUST NOT delegate back into GNS and should
   only follow the DNS specifications.  For example, names contained in
   DNS CNAME records MUST NOT be interpreted as GNS names.

   GNS resolvers SHOULD offer a configuration option to disable DNS
   processing to avoid information leakage and provide a consistent
   security profile for all name resolutions.  Such resolvers would
   return an empty record set upon encountering a GNS2DNS record during
   the recursion.  However, if GNS2DNS records are encountered in the
   record set for the apex label and a GNS2DNS record is explicitly
   requested by the application, such records MUST still be returned,
   even if DNS support is disabled by the GNS resolver configuration.

7.3.3.  BOX

   When a BOX record is received, a GNS resolver must unbox it if the
   name to be resolved continues with "_SERVICE._PROTO".  Otherwise, the
   BOX record is to be left untouched.  This way, TLSA (and SRV) records
   do not require a separate network request, and TLSA records become
   inseparable from the corresponding address records.

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7.3.4.  Zone Delegation Records

   When the resolver encounters a record of a supported zone delegation
   record type (such as PKEY or EDKEY) and the remainder of the name is
   not empty, resolution continues recursively with the remainder of the
   name in the GNS zone specified in the delegation record.
   Implementations MUST NOT allow multiple different zone delegations
   under a single label.  Implementations MAY support any subset of
   ztypes.  Handling of Implementations MUST NOT process zone delegation
   for the apex label "@".  Upon encountering a zone delegation record
   under this label, resolution fails and an error MUST be returned.
   The implementation MAY choose not to return the reason for the
   failure, merely impacting troubleshooting information for the user.

   If the remainder of the name to resolve is empty and we have received
   a record set containing only a single delegation record, the
   recursion is continued with the record value as authoritative zone
   and the apex label "@" as remaining name.  Except in the case where
   the desired record type as specified by the application is equal to
   the ztype, in which case the delegation record is returned.

7.3.5.  NICK

   NICK records are only relevant to the recursive resolver if the
   record set in question is the final result which is to be returned to
   the application.  The encountered NICK records may either be
   supplemental (see Section 5) or non-supplemental.  If the NICK record
   is supplemental, the resolver only returns the record set if one of
   the non-supplemental records matches the queried record type.  It is
   possible that one record set contains both supplemental and non-
   supplemental NICK records.

   The differentiation between a supplemental and non-supplemental NICK
   record allows the application to match the record to the
   authoritative zone.  Consider the following example:

   Query: alice.example (type=A)
   Result:
   A: 192.0.2.1
   NICK: eve (non-Supplemental)

   In this example, the returned NICK record is non-supplemental.  For
   the application, this means that the NICK belongs to the zone
   "alice.example" and is published under the apex label along with an A
   record.  The NICK record should be interpreted as: The zone defined
   by "alice.example" wants to be referred to as "eve".  In contrast,
   consider the following:

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   Query: alice.example (type=AAAA)
   Result:
   AAAA: 2001:DB8::1
   NICK: john (Supplemental)

   In this case, the NICK record is marked as supplemental.  This means
   that the NICK record belongs to the zone "example" and is published
   under the label "alice" along with an A record.  The NICK record
   should be interpreted as: The zone defined by "example" wants to be
   referred to as "john".  This distinction is likely useful for other
   records published as supplemental.

8.  Internationalization and Character Encoding

   All labels in GNS are encoded in UTF-8 [RFC3629].  Labels MUST be
   canonicalized using Normalization Form C (NFC) [Unicode-UAX15].  This
   does not include any DNS names found in DNS records, such as CNAME
   records, which are internationalized through the IDNA specifications
   [RFC5890].

9.  Security and Privacy Considerations

9.1.  Availability

   In order to ensure availability of records beyond their absolute
   expiration times, implementations MAY allow to locally define
   relative expiration time values of records.  Records can then be
   published recurringly with updated absolute expiration times by the
   implementation.

   Implementations MAY allow users to manage private records in their
   zones that are not published in the storage.  Private records are
   considered just like regular records when resolving labels in local
   zones, but their data is completely unavailable to non-local users.

9.2.  Agility

   The security of cryptographic systems depends on both the strength of
   the cryptographic algorithms chosen and the strength of the keys used
   with those algorithms.  The security also depends on the engineering
   of the protocol used by the system to ensure that there are no non-
   cryptographic ways to bypass the security of the overall system.
   This is why developers of applications managing GNS zones SHOULD
   select a default ztype considered secure at the time of releasing the
   software.  For applications targeting end users that are not expected
   to understand cryptography, the application developer MUST NOT leave
   the ztype selection of new zones to end users.

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   This document concerns itself with the selection of cryptographic
   algorithms used in GNS.  The algorithms identified in this document
   are not known to be broken (in the cryptographic sense) at the
   current time, and cryptographic research so far leads us to believe
   that they are likely to remain secure into the foreseeable future.
   However, this is not necessarily forever, and it is expected that new
   revisions of this document will be issued from time to time to
   reflect the current best practices in this area.

   In terms of crypto-agility, whenever the need for an updated
   cryptographic scheme arises to, for example, replace ECDSA over
   Ed25519 for PKEY records it may simply be introduced through a new
   record type.  Such a new record type may then replace the delegation
   record type for future records.  The old record type remains and
   zones can iteratively migrate to the updated zone keys.  To ensure
   that implementations correctly generate an error message when
   encountering a ztype that they do not support, current and future
   delegation records must always have the CRITICAL flag set.

9.3.  Cryptography

   GNS PKEY zone keys use ECDSA over Ed25519.  This is an unconventional
   choice, as ECDSA is usually used with other curves.  However,
   traditional ECDSA curves are problematic for a range of reasons
   described in the Curve25519 and EdDSA papers.  Using EdDSA directly
   is also not possible, as a hash function is used on the private key
   which destroys the linearity that the GNU Name System depends upon.
   We are not aware of anyone suggesting that using Ed25519 instead of
   another common curve of similar size would lower the security of
   ECDSA.  GNS uses 256-bit curves because that way the encoded (public)
   keys fit into a single DNS label, which is good for usability.

   In order to ensure ciphertext indistinguishability, care must be
   taken with respect to the initialization vector in the counter block.
   In our design, the IV always includes the expiration time of the
   record block.  When applications store records with relative
   expiration times, monotonicity is implicitly ensured because each
   time a block is published into the storage, its IV is unique as the
   expiration time is calculated dynamically and increases monotonically
   with the system time.  Still, an implementation MUST ensure that when
   relative expiration times are decreased, the expiration time of the
   next record block MUST be after the last published block.  For
   records where an absolute expiration time is used, the implementation
   MUST ensure that the expiration time is always increased when the
   record data changes.  For example, the expiration time on the wire
   may be increased by a single microsecond even if the user did not
   request a change.  In case of deletion of all resource records under
   a label, the implementation MUST keep track of the last absolute

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   expiration time of the last published resource block.
   Implementations MAY use a PADDING record as a tombstone that
   preserves the last absolute expiration time, but then MUST take care
   to not publish a block with just a PADDING record.  When new records
   are added under this label later, the implementation MUST ensure that
   the expiration times are after the last published block.  Finally, in
   order to ensure monotonically increasing expiration times the
   implementation MUST keep a local record of the last time obtained
   from the system clock, so as to construct a monotonic clock in case
   the system clock jumps backwards.

9.4.  Abuse Mitigation

   GNS names are UTF-8 strings.  Consequently, GNS faces similar issues
   with respect to name spoofing as DNS does for internationalized
   domain names.  In DNS, attackers may register similar sounding or
   looking names (see above) in order to execute phishing attacks.  GNS
   zone administrators must take into account this attack vector and
   incorporate rules in order to mitigate it.

   Further, DNS can be used to combat illegal content on the internet by
   having the respective domains seized by authorities.  However, the
   same mechanisms can also be abused in order to impose state
   censorship, which is one of the motivations behind GNS.  Hence, such
   a seizure is, by design, difficult to impossible in GNS.

9.5.  Zone Management

   In GNS, zone administrators need to manage and protect their zone
   keys.  Once a zone key is lost, it cannot be recovered or revoked.
   Revocation messages may be pre-calculated if revocation is required
   in case a zone key is lost.  Zone administrators, and for GNS this
   includes end-users, are required to responsibly and diligently
   protect their cryptographic keys.  GNS supports offline signing of
   records.

   Similarly, users are required to manage their local start zone
   configuration.  In order to ensure integrity and availability or
   names, users must ensure that their local start zone information is
   not compromised or outdated.  It can be expected that the processing
   of zone revocations and an initial start zone is provided with a GNS
   implementation ("drop shipping").  Shipping an initial start zone
   with an entry for the root (".") effectively establishes a root zone.
   Extension and customization of the zone is at the full discretion of
   the user.

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   While implementations following this specification will be
   interoperable, if two implementations connect to different storages
   they are mutually unreachable.  This may lead to a state where a
   record may exist in the global namespace for a particular name, but
   the implementation is not communicating with the storage and is hence
   unable to resolve it.  This situation is similar to a split-horizon
   DNS configuration.  Which storages are implemented usually depends on
   the application it is built for.  The storage used will most likely
   depend on the specific application context using GNS resolution.  For
   example, one application may be the resolution of hidden services
   within the Tor network, which may suggest using Tor routers for
   storage.  Implementations of "aggregated" storages are conceivable,
   but are expected to be the exception.

9.6.  Impact of DHTs as Underlying Storage

   This document does not specify the properties of the underlying
   storage which is required by any GNS implementation.  It is important
   to note that the properties of the underlying storage are directly
   inherited by the GNS implementation.  This includes both security as
   well as other non-functional properties such as scalability and
   performance.  Implementers should take great care when selecting or
   implementing a DHT for use as storage in a GNS implementation.  DHTs
   with reasonable security and performance properties exist [R5N].  It
   should also be taken into consideration that GNS implementations
   which build upon different DHT overlays are unlikely to be
   interoperable with each other.

9.7.  Revocations

   Zone administrators are advised to pre-generate zone revocations and
   to securely store the revocation information in case the zone key is
   lost, compromised or replaced in the future.  Pre-calculated
   revocations may become invalid due to expirations or protocol changes
   such as epoch adjustments.  Consequently, implementers and users must
   take precautions in order to manage revocations accordingly.

   Revocation payloads do NOT include a 'new' key for key replacement.
   Inclusion of such a key would have two major disadvantages:

   1.  If a revocation is published after a private key was compromised,
       allowing key replacement would be dangerous: if an adversary took
       over the private key, the adversary could then broadcast a
       revocation with a key replacement.  For the replacement, the
       compromised owner would have no chance to issue even a
       revocation.  Thus, allowing a revocation message to replace a
       private key makes dealing with key compromise situations worse.

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   2.  Sometimes, key revocations are used with the objective of
       changing cryptosystems.  Migration to another cryptosystem by
       replacing keys via a revocation message would only be secure as
       long as both cryptosystems are still secure against forgery.
       Such a planned, non-emergency migration to another cryptosystem
       should be done by running zones for both cipher systems in
       parallel for a while.  The migration would conclude by revoking
       the legacy zone key only once it is deemed no longer secure, and
       hopefully after most users have migrated to the replacement.

9.8.  Label Guessing

   Record blocks are published in encrypted form using keys derived from
   the zone key and record label.  Zone administrators should carefully
   consider if the label and zone key may be public or if those should
   be used and considered as a shared secret.  Unlike zone keys, labels
   can also be guessed by an attacker in the network observing queries
   and responses.  Given a known and targeted zone key, the use of well
   known or easily guessable labels effectively result in general
   disclosure of the records to the public.  If the labels and hence the
   records should be kept secret except to those knowing a secret label
   and the zone in which to look, the label must be chosen accordingly.
   It is recommended to then use a label with sufficient entropy as to
   prevent guessing attacks.

   It should be noted that this attack on labels only applies if the
   zone key is somehow disclosed to the adversary.  GNS itself does not
   disclose it during a lookup or when resource records are published as
   the zone keys are blinded beforehand.  However, zone keys do become
   public during revocation.

10.  GANA Considerations

   GANA [GANA] manages the "GNU Name System Record Types" registry.
   Each entry has the following format:

   *  Name: The name of the record type (case-insensitive ASCII string,
      restricted to alphanumeric characters.  For zone delegation
      records, the assigned number represents the ztype value of the
      zone.

   *  Number: 32-bit, above 65535

   *  Comment: Optionally, a brief English text describing the purpose
      of the record type (in UTF-8)

   *  Contact: Optionally, the contact information of a person to
      contact for further information.

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   *  References: Optionally, references describing the record type
      (such as an RFC)

   The registration policy for this registry is "First Come First
   Served".  This policy is modeled on that described in [RFC8126], and
   describes the actions taken by GANA:

   Adding new records is possible after expert review, using a first-
   come-first-served policy for unique name allocation.  Experts are
   responsible to ensure that the chosen "Name" is appropriate for the
   record type.  The registry will assign a unique number for the entry.

   The current contact(s) for expert review are reachable at gns-
   registry@gnunet.org.

   Any request MUST contain a unique name and a point of contact.  The
   contact information MAY be added to the registry given the consent of
   the requester.  The request MAY optionally also contain relevant
   references as well as a descriptive comment as defined above.

   GANA is requested to populate this registry as listed in Figure 21.

   Number | Name    | Contact | References | Comment
   -------+---------+---------+------------+-------------------------
   65536  | PKEY    | N/A     | [This.I-D] | GNS zone delegation (PKEY)
   65537  | NICK    | N/A     | [This.I-D] | GNS zone nickname
   65538  | LEHO    | N/A     | [This.I-D] | GNS legacy hostname
   65540  | GNS2DNS | N/A     | [This.I-D] | Delegation to DNS
   65541  | BOX     | N/A     | [This.I-D] | Boxed records
   65551  | REDIRECT| N/A     | [This.I-D] | Redirection record.
   65556  | EDKEY   | N/A     | [This.I-D] | GNS zone delegation (EDKEY)

                                 Figure 21

   The GANA Resource Record Registry.

   GANA is requested to amend the "GNUnet Signature Purpose" registry as
   illustrated in Figure 22.

   Purpose | Name            | References | Comment
   --------+-----------------+------------+--------------------------
     3     | GNS_REVOCATION  | [This.I-D] | GNS zone key revocation
    15     | GNS_RECORD_SIGN | [This.I-D] | GNS record set signature

                                 Figure 22

   Requested Changes in the GANA GNUnet Signature Purpose Registry.

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11.  IANA Considerations

   This document makes no requests for IANA action.  This section may be
   removed on publication as an RFC.

12.  Implementation and Deployment Status

   There are two implementations conforming to this specification
   written in C and Go, respectively.  The C implementation as part of
   GNUnet [GNUnetGNS] represents the original and reference
   implementation.  The Go implementation [GoGNS] demonstrates how two
   implementations of GNS are interoperable given that they are built on
   top of the same underlying DHT storage.

   Currently, the GNUnet peer-to-peer network [GNUnet] is an active
   deployment of GNS on top of its [R5N] DHT.  The [GoGNS]
   implementation uses this deployment by building on top of the GNUnet
   DHT services available on any GNUnet peer.  It shows how GNS
   implementations can attach to this existing deployment and
   participate in name resolution as well as zone publication.

   The self-sovereign identity system re:claimID [reclaim] is using GNS
   in order to selectively share identity attributes and attestations
   with third parties.

   The Ascension tool [Ascension] facilitates the migration of DNS zones
   to GNS zones by translating information retrieved from a DNS zone
   transfer into a GNS zone.

13.  Acknowledgements

   The authors thank D.  J.  Bernstein, A.  Farrel and S.  Bortzmeyer
   for their insightful reviews.  We thank NLnet and NGI DISCOVERY for
   funding work on the GNU Name System.

14.  Normative References

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

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   [RFC2782]  Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
              specifying the location of services (DNS SRV)", RFC 2782,
              DOI 10.17487/RFC2782, February 2000,
              <https://www.rfc-editor.org/info/rfc2782>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
              2003, <https://www.rfc-editor.org/info/rfc3629>.

   [RFC3686]  Housley, R., "Using Advanced Encryption Standard (AES)
              Counter Mode With IPsec Encapsulating Security Payload
              (ESP)", RFC 3686, DOI 10.17487/RFC3686, January 2004,
              <https://www.rfc-editor.org/info/rfc3686>.

   [RFC3826]  Blumenthal, U., Maino, F., and K. McCloghrie, "The
              Advanced Encryption Standard (AES) Cipher Algorithm in the
              SNMP User-based Security Model", RFC 3826,
              DOI 10.17487/RFC3826, June 2004,
              <https://www.rfc-editor.org/info/rfc3826>.

   [RFC5237]  Arkko, J. and S. Bradner, "IANA Allocation Guidelines for
              the Protocol Field", BCP 37, RFC 5237,
              DOI 10.17487/RFC5237, February 2008,
              <https://www.rfc-editor.org/info/rfc5237>.

   [RFC5869]  Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
              Key Derivation Function (HKDF)", RFC 5869,
              DOI 10.17487/RFC5869, May 2010,
              <https://www.rfc-editor.org/info/rfc5869>.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, DOI 10.17487/RFC5890, August 2010,
              <https://www.rfc-editor.org/info/rfc5890>.

   [RFC5891]  Klensin, J., "Internationalized Domain Names in
              Applications (IDNA): Protocol", RFC 5891,
              DOI 10.17487/RFC5891, August 2010,
              <https://www.rfc-editor.org/info/rfc5891>.

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   [RFC6234]  Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
              (SHA and SHA-based HMAC and HKDF)", RFC 6234,
              DOI 10.17487/RFC6234, May 2011,
              <https://www.rfc-editor.org/info/rfc6234>.

   [RFC6895]  Eastlake 3rd, D., "Domain Name System (DNS) IANA
              Considerations", BCP 42, RFC 6895, DOI 10.17487/RFC6895,
              April 2013, <https://www.rfc-editor.org/info/rfc6895>.

   [RFC6979]  Pornin, T., "Deterministic Usage of the Digital Signature
              Algorithm (DSA) and Elliptic Curve Digital Signature
              Algorithm (ECDSA)", RFC 6979, DOI 10.17487/RFC6979, August
              2013, <https://www.rfc-editor.org/info/rfc6979>.

   [RFC7748]  Langley, A., Hamburg, M., and S. Turner, "Elliptic Curves
              for Security", RFC 7748, DOI 10.17487/RFC7748, January
              2016, <https://www.rfc-editor.org/info/rfc7748>.

   [RFC8032]  Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
              Signature Algorithm (EdDSA)", RFC 8032,
              DOI 10.17487/RFC8032, January 2017,
              <https://www.rfc-editor.org/info/rfc8032>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8499]  Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
              Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
              January 2019, <https://www.rfc-editor.org/info/rfc8499>.

   [RFC9106]  Biryukov, A., Dinu, D., Khovratovich, D., and S.
              Josefsson, "Argon2 Memory-Hard Function for Password
              Hashing and Proof-of-Work Applications", RFC 9106,
              DOI 10.17487/RFC9106, September 2021,
              <https://www.rfc-editor.org/info/rfc9106>.

   [GANA]     GNUnet e.V., "GNUnet Assigned Numbers Authority (GANA)",
              April 2020, <https://gana.gnunet.org/>.

   [MODES]    Dworkin, M., "Recommendation for Block Cipher Modes of
              Operation: Methods and Techniques", December 2001,
              <https://doi.org/10.6028/NIST.SP.800-38A>.

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   [CrockfordB32]
              Douglas, D., "Base32", March 2019,
              <https://www.crockford.com/base32.html>.

   [XSalsa20] Bernstein, D., "Extending the Salsa20 nonce", 2011,
              <https://cr.yp.to/snuffle/xsalsa-20110204.pdf>.

   [Unicode-UAX15]
              Consortium, T. U., "Unicode Standard Annex #15: Unicode
              Normalization Forms, Revision 31", September 2009,
              <http://www.unicode.org/reports/tr15/tr15-31.html>.

15.  Informative References

   [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "DNS Security Introduction and Requirements",
              RFC 4033, DOI 10.17487/RFC4033, March 2005,
              <https://www.rfc-editor.org/info/rfc4033>.

   [RFC7363]  Maenpaa, J. and G. Camarillo, "Self-Tuning Distributed
              Hash Table (DHT) for REsource LOcation And Discovery
              (RELOAD)", RFC 7363, DOI 10.17487/RFC7363, September 2014,
              <https://www.rfc-editor.org/info/rfc7363>.

   [RFC8324]  Klensin, J., "DNS Privacy, Authorization, Special Uses,
              Encoding, Characters, Matching, and Root Structure: Time
              for Another Look?", RFC 8324, DOI 10.17487/RFC8324,
              February 2018, <https://www.rfc-editor.org/info/rfc8324>.

   [Tor224]   Goulet, D., Kadianakis, G., and N. Mathewson, "Next-
              Generation Hidden Services in Tor", November 2013,
              <https://gitweb.torproject.org/torspec.git/tree/
              proposals/224-rend-spec-ng.txt#n2135>.

   [SDSI]     Rivest, R. and B. Lampson, "SDSI - A Simple Distributed
              Security Infrastructure", April 1996,
              <http://people.csail.mit.edu/rivest/Sdsi10.ps>.

   [Kademlia] Maymounkov, P. and D. Mazieres, "Kademlia: A peer-to-peer
              information system based on the xor metric.", 2002,
              <http://css.csail.mit.edu/6.824/2014/papers/kademlia.pdf>.

   [ed25519]  Bernstein, D., Duif, N., Lange, T., Schwabe, P., and B.
              Yang, "High-Speed High-Security Signatures", 2011,
              <http://link.springer.com/
              chapter/10.1007/978-3-642-23951-9_9>.

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   [GNS]      Wachs, M., Schanzenbach, M., and C. Grothoff, "A
              Censorship-Resistant, Privacy-Enhancing and Fully
              Decentralized Name System", 2014,
              <https://sci-hub.st/10.1007/978-3-319-12280-9_9>.

   [R5N]      Evans, N. S. and C. Grothoff, "R5N: Randomized recursive
              routing for restricted-route networks", 2011,
              <https://sci-hub.st/10.1109/ICNSS.2011.6060022>.

   [SecureNS] Grothoff, C., Wachs, M., Ermert, M., and J. Appelbaum,
              "Towards secure name resolution on the Internet", 2018,
              <https://sci-hub.st/https://doi.org/10.1016/
              j.cose.2018.01.018>.

   [GNUnetGNS]
              GNUnet e.V., "The GNUnet GNS Implementation",
              <https://git.gnunet.org/gnunet.git/tree/src/gns>.

   [Ascension]
              GNUnet e.V., "The Ascension Implementation",
              <https://git.gnunet.org/ascension.git>.

   [GNUnet]   GNUnet e.V., "The GNUnet Project", <https://gnunet.org>.

   [reclaim]  GNUnet e.V., "The GNUnet Project",
              <https://reclaim.gnunet.org>.

   [GoGNS]    Fix, B., "The Go GNS Implementation",
              <https://github.com/bfix/gnunet-
              go/tree/master/src/gnunet/service/gns>.

Appendix A.  Base32GNS

   This table defines the encode symbol and decode symbol for a given
   symbol value.  It can be used to implement the encoding by reading it
   as: A character "A" or "a" is decoded to a 5 bit value 10 when
   decoding.  A 5 bit block with a value of 18 is encoded to the
   character "J" when encoding.  If the bit length of the byte string to
   encode is not a multiple of 5 it is padded to the next multiple with
   zeroes.  In order to further increase tolerance for failures in
   character recognition, the letter "U" MUST be decoded to the same
   value as the letter "V" in Base32GNS.

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   Symbol      Decode            Encode
   Value       Symbol            Symbol
   0           0 O o             0
   1           1 I i L l         1
   2           2                 2
   3           3                 3
   4           4                 4
   5           5                 5
   6           6                 6
   7           7                 7
   8           8                 8
   9           9                 9
   10          A a               A
   11          B b               B
   12          C c               C
   13          D d               D
   14          E e               E
   15          F f               F
   16          G g               G
   17          H h               H
   18          J j               J
   19          K k               K
   20          M m               M
   21          N n               N
   22          P p               P
   23          Q q               Q
   24          R r               R
   25          S s               S
   26          T t               T
   27          V v U u           V
   28          W w               W
   29          X x               X
   30          Y y               Y
   31          Z z               Z

                                 Figure 23

   The Base32GNS Alphabet Including the Additional U Encode Symbol.

Appendix B.  Test Vectors

   The following are test vectors for the Base32GNS encoding used for
   zTLDs.  The strings are encoded without the zero terminator.

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   Base32GNS-Encode:
     Input string: "Hello World"
     Output string: "91JPRV3F41BPYWKCCG"

     Input bytes: 474e55204e616d652053797374656d
     Output string: "8X75A82EC5PPA82KF5SQ8SBD"

   Base32GNS-Decode:
     Input string: "91JPRV3F41BPYWKCCG"
     Output string: "Hello World"

     Input string: "91JPRU3F41BPYWKCCG"
     Output string: "Hello World"

   The following represents a test vector for a record set with a DNS
   record of type "A" as well as a GNS record of type "PKEY" under the
   label "test".

   Zone private key (d, big-endian):
   50d7b652a4efeadf
   f37396909785e595
   2171a02178c8e7d4
   50fa907925fafd98

   Zone identifier (ztype|zkey):
   00010000677c477d
   2d93097c85b195c6
   f96d84ff61f5982c
   2c4fe02d5a11fedf
   b0c2901f

   Encoded zone identifier (zkl = zTLD):
   000G0037FH3QTBCK15Y8BCCNRVWPV17ZC7TSGB1C9ZG2TPGHZVFV1GMG3W

   Label: testdelegation
   RRCOUNT: 1

   Record #0
   EXPIRATION: 2463385894000000
   DATA_SIZE: 36
   TYPE: 65536
   FLAGS: 01000000

   DATA:
   0001000021e3b30f
   f93bc6d35ac8c6e0

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   e13afdff794cb7b4
   4bbbc748d259d0a0
   284dbe84

   RDATA:
   0008c06fb9281580
   0024000100010000
   0001000021e3b30f
   f93bc6d35ac8c6e0
   e13afdff794cb7b4
   4bbbc748d259d0a0
   284dbe84

   Encryption NONCE|EXPIRATION|BLOCK COUNTER:
   e90a00610008c06f
   b928158000000001

   Encryption key (K):
   864e7138eae7fd91
   a30136899c132b23
   acebdb2cef43cb19
   f6bf55b67db9b3b3

   Storage key (q):
   4adc67c5ecee9f76
   986abd71c2224a3d
   ce2e917026c9a09d
   fd44cef3d20f55a2
   7332725a6c8afbbb
   b0f7ec9af1cc4264
   1299406b04fd9b5b
   5791f86c4b08d5f4

   BDATA:
   41dc7b5f2176ba59
   199cafb9e3c82579
   71b21ccb6de51d38
   bd2a21e9322c6af8
   4243e8de876b5b76
   37462e79b2c162db
   4014d5c9

   RRBLOCK:
   000000a400010000
   182bb636eda79f79
   5711bc2708adbb24
   2a60446ad3c30803
   121d03d348b7ceb6

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   01a968a5eac3cb95
   ed58c1c5386f4ab6
   539edd8099b4893a
   be83f242115e3e35
   03965dc924a6001a
   e94ecab9b2f25c4c
   6fdc7ffbe9f3b2a2
   854b321b1d7ea9ab
   0008c06fb9281580
   41dc7b5f2176ba59
   199cafb9e3c82579
   71b21ccb6de51d38
   bd2a21e9322c6af8
   4243e8de876b5b76
   37462e79b2c162db
   4014d5c9

   Zone private key (d, big-endian):
   50d7b652a4efeadf
   f37396909785e595
   2171a02178c8e7d4
   50fa907925fafd98

   Zone identifier (ztype|zkey):
   00010000677c477d
   2d93097c85b195c6
   f96d84ff61f5982c
   2c4fe02d5a11fedf
   b0c2901f

   Encoded zone identifier (zkl = zTLD):
   000G0037FH3QTBCK15Y8BCCNRVWPV17ZC7TSGB1C9ZG2TPGHZVFV1GMG3W

   Label: testset
   RRCOUNT: 3

   Record #0
   EXPIRATION: 2463385894000000
   DATA_SIZE: 16
   TYPE: 28
   FLAGS: 00000000

   DATA:
   0000000000000000
   00000000deadbeef

   Record #1
   EXPIRATION: 49556645701000000

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   DATA_SIZE: 9
   TYPE: 65537
   FLAGS: 00800000

   DATA:
   536f6d65206e6963
   6b

   Record #2
   EXPIRATION: 6091321688
   DATA_SIZE: 11
   TYPE: 16
   FLAGS: 04400000

   DATA:
   48656c6c6f20576f
   726c64

   RDATA:
   0008c06fb9281580
   001000000000001c
   0000000000000000
   00000000deadbeef
   00b00f81b7449b40
   0009800000010001
   536f6d65206e6963
   6b000000016b1231
   58000b4004000000
   1048656c6c6f2057
   6f726c6400000000
   0000000000000000
   0000000000000000
   0000000000000000
   0000000000000000
   0000000000000000

   Encryption NONCE|EXPIRATION|BLOCK COUNTER:
   4edb104e0005d78a
   44e4e6c800000001

   Encryption key (K):
   4a7d3f21f67c377e
   ad2cb255b6c05930
   6287e78caeff4c80
   f08e1df327900d21

   Storage key (q):
   e8f9a842256e825b

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   f40e802ab2a81a3c
   31d621100b4adec0
   3c152e22cdbcab0d
   d5dde37815887f74
   950b22179269e6b3
   2b75928dd80111de
   3e12eca5517ae246

   BDATA:
   a6b26ac00e485ddd
   26e8db68e3eaba01
   b5760ae197f70e28
   39cc9e4ac40668f4
   61285e42d8e7c397
   cfc90e8042106666
   9a0506edccfacb1b
   520103c2a68eb06d
   770c7bd65e6810c3
   88e192cc313f924b
   ffe67ce114694f20
   03d851c7fe5623b2
   5eb0fad6bbdf917b
   e7eac3a9ec795dd4
   a9c8b4c683896b2c
   69d4d5ae8dafd93a

   RRBLOCK:
   000000f000010000
   d84c242613691d2f
   2150f55b89ee03ca
   0b13f9fa6905eb17
   acedcbc55518b8aa
   042c1e6e6e3aa52a
   6538a91fd3d5e9cd
   987edb1106f3f864
   fea111382f5a0a42
   0b954ccb4dc6e9e1
   3cbec65e7ae021ec
   7c4f7830aa158423
   da439dc17fee7586
   0005d78a44e4e6c8
   a6b26ac00e485ddd
   26e8db68e3eaba01
   b5760ae197f70e28
   39cc9e4ac40668f4
   61285e42d8e7c397
   cfc90e8042106666
   9a0506edccfacb1b

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   520103c2a68eb06d
   770c7bd65e6810c3
   88e192cc313f924b
   ffe67ce114694f20
   03d851c7fe5623b2
   5eb0fad6bbdf917b
   e7eac3a9ec795dd4
   a9c8b4c683896b2c
   69d4d5ae8dafd93a

   The following represents a test vector for a record set with a DNS
   record of type "A" as well as a GNS record of type "EDKEY" under the
   label "test".

   Zone private key (d):
   5af7020ee1916032
   8832352bbc6a68a8
   d71a7cbe1b929969
   a7c66d415a0d8f65

   Zone identifier (ztype|zkey):
   000100143cf4b924
   032022f0dc505814
   53b85d93b047b63d
   446c5845cb48445d
   db96688f

   Encoded zone identifier (zkl = zTLD):
   000G051WYJWJ80S04BRDRM2R2H9VGQCKP13VCFA4DHC4BJT88HEXQ5K8HW

   Label: testdelegation
   RRCOUNT: 1

   Record #0
   EXPIRATION: 2463385894000000
   DATA_SIZE: 36
   TYPE: 65536
   FLAGS: 01000000

   DATA:
   0001000021e3b30f
   f93bc6d35ac8c6e0
   e13afdff794cb7b4
   4bbbc748d259d0a0
   284dbe84

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   RDATA:
   0008c06fb9281580
   0024000100010000
   0001000021e3b30f
   f93bc6d35ac8c6e0
   e13afdff794cb7b4
   4bbbc748d259d0a0
   284dbe84

   Encryption NONCE|EXPIRATION:
   98132ea86859d35c
   88bfd317fa991bcb
   0008c06fb9281580

   Encryption key (K):
   85c429a9567aa633
   411a9691e9094c45
   281672be586034aa
   e4a2a2cc716159e2

   Storage key (q):
   abaabac0e1249459
   75988395aac0241e
   5559c41c4074e255
   7b9fe6d154b614fb
   cdd47fc7f51d786d
   c2e0b1ece76037c0
   a1578c384ec61d44
   5636a94e880329e9

   BDATA:
   7d9ecea3c19ef07b
   0db1fab44c5e4477
   6ea8d8894e904a0c
   35ed1c5c2ff2ed93
   bd204b3fcae98192
   fad94afbc5bba3a6
   de538c01c7e1f65e
   2a883cc068c02109
   7afd7330

   RRBLOCK:
   000000b400010014
   9bf233198c6d53bb
   dbac495cabd91049
   a684af3f4051baca
   b0dcf21c8cf27a1a
   69ac3485946796d1

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   e31837f569d71e06
   e79c4777ab9c41fa
   29cdd198464aac3d
   aaeea2c192eb6e71
   1d0dc7bb76994eca
   ab837e402ba2c994
   4df155b6e96fdf0a
   0008c06fb9281580
   7d9ecea3c19ef07b
   0db1fab44c5e4477
   6ea8d8894e904a0c
   35ed1c5c2ff2ed93
   bd204b3fcae98192
   fad94afbc5bba3a6
   de538c01c7e1f65e
   2a883cc068c02109
   7afd7330

   Zone private key (d):
   5af7020ee1916032
   8832352bbc6a68a8
   d71a7cbe1b929969
   a7c66d415a0d8f65

   Zone identifier (ztype|zkey):
   000100143cf4b924
   032022f0dc505814
   53b85d93b047b63d
   446c5845cb48445d
   db96688f

   Encoded zone identifier (zkl = zTLD):
   000G051WYJWJ80S04BRDRM2R2H9VGQCKP13VCFA4DHC4BJT88HEXQ5K8HW

   Label: testset
   RRCOUNT: 3

   Record #0
   EXPIRATION: 2463385894000000
   DATA_SIZE: 16
   TYPE: 28
   FLAGS: 00000000

   DATA:
   0000000000000000
   00000000deadbeef

   Record #1

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   EXPIRATION: 49556645701000000
   DATA_SIZE: 9
   TYPE: 65537
   FLAGS: 00800000

   DATA:
   536f6d65206e6963
   6b

   Record #2
   EXPIRATION: 6091321688
   DATA_SIZE: 11
   TYPE: 16
   FLAGS: 04400000

   DATA:
   48656c6c6f20576f
   726c64

   RDATA:
   0008c06fb9281580
   001000000000001c
   0000000000000000
   00000000deadbeef
   00b00f81b7449b40
   0009800000010001
   536f6d65206e6963
   6b000000016b1231
   58000b4004000000
   1048656c6c6f2057
   6f726c6400000000
   0000000000000000
   0000000000000000
   0000000000000000
   0000000000000000
   0000000000000000

   Encryption NONCE|EXPIRATION:
   0a27e1f82798d680
   4285c81ef29391f9
   0005d78a44e4ff82

   Encryption key (K):
   227730f8c97f94ab
   5de3645aa731be24
   769f04cacb88312d
   e8e5102909693488

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   Storage key (q):
   60c6e5b3442eb232
   837e70205f26ca16
   539f1354692fbeb3
   05541efd0e3216cc
   9373d3e2c6f8fa1d
   1e49cfd9c19cb654
   0621377eb989461c
   f09676309323b000

   BDATA:
   dfc0aa69cee85288
   434b48d487ed3911
   5118213b7b2efe73
   9067c6f6c0e83d59
   7d9288b018e73b66
   264ee8587d026c60
   bd2ff2e3d50a7d49
   1b53803c8ff4eb3c
   03197178d551434e
   20851fda85950116
   5a6f51dc9accaf5a
   daf5ed94a707ffb9
   2854ef15c67fb1ec
   465f168d480f6436
   a1c5affccef33fdd
   0b99ea4719debbfd
   c1e7e52aaa546b3f
   4c4c91d7f1aba812

   RRBLOCK:
   0000010000010014
   dd541a46885a250a
   27db63b2b1c07c04
   3137271edc77df52
   0a30b7bb909060f6
   3b8be702f815cb02
   f3186874a331d87f
   0263393fa66b6197
   52b35fd117f27b73
   86ab6924bd948de9
   cd5f512d3ca370c5
   3bfccfc5238516cc
   0ddeacf65b145709
   0005d78a44e4ff82
   dfc0aa69cee85288
   434b48d487ed3911
   5118213b7b2efe73

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   9067c6f6c0e83d59
   7d9288b018e73b66
   264ee8587d026c60
   bd2ff2e3d50a7d49
   1b53803c8ff4eb3c
   03197178d551434e
   20851fda85950116
   5a6f51dc9accaf5a
   daf5ed94a707ffb9
   2854ef15c67fb1ec
   465f168d480f6436
   a1c5affccef33fdd
   0b99ea4719debbfd
   c1e7e52aaa546b3f
   4c4c91d7f1aba812

   The following is an example revocation for a zone:

   Zone private key (d, big-endian scalar):
   6fea32c05af58bfa
   979553d188605fd5
   7d8bf9cc263b78d5
   f7478c07b998ed70

   Zone identifier (ztype|zkey):
   000100002ca223e8
   79ecc4bbdeb5da17
   319281d63b2e3b69
   55f1c3775c804a98
   d5f8ddaa

   Encoded zone identifier (zkl = zTLD):
   000G001CM8HYGYFCRJXXXDET2WRS50EP7CQ3PTANY71QEQ409ACDBY6XN8

   Difficulty (5 base difficulty + 2 epochs): 7

   Signed message:
   0000003400000003
   0005d66da3598127
   000100002ca223e8
   79ecc4bbdeb5da17
   319281d63b2e3b69
   55f1c3775c804a98
   d5f8ddaa

   Proof:

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   0005d66da3598127
   0000395d1827c000
   3ab877d07570f2b8
   3ab877d07570f332
   3ab877d07570f4f5
   3ab877d07570f50f
   3ab877d07570f537
   3ab877d07570f599
   3ab877d07570f5cd
   3ab877d07570f5d9
   3ab877d07570f66a
   3ab877d07570f69b
   3ab877d07570f72f
   3ab877d07570f7c3
   3ab877d07570f843
   3ab877d07570f8d8
   3ab877d07570f91b
   3ab877d07570f93a
   3ab877d07570f944
   3ab877d07570f98a
   3ab877d07570f9a7
   3ab877d07570f9b0
   3ab877d07570f9df
   3ab877d07570fa05
   3ab877d07570fa3e
   3ab877d07570fa63
   3ab877d07570fa84
   3ab877d07570fa8f
   3ab877d07570fa91
   3ab877d07570fad6
   3ab877d07570fb0a
   3ab877d07570fc0f
   3ab877d07570fc43
   3ab877d07570fca5
   000100002ca223e8
   79ecc4bbdeb5da17
   319281d63b2e3b69
   55f1c3775c804a98
   d5f8ddaa053b0259
   700039187d1da461
   3531502bc4a4eecc
   c69900d24f8aac54
   30f28fc509270133
   1f178e290fe06e82
   ce2498ce7b23a340
   58e3d6a2f247e92b
   c9d7b9ab

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Authors' Addresses

   Martin Schanzenbach
   GNUnet e.V.
   Boltzmannstrasse 3
   85748 Garching
   Germany

   Email: schanzen@gnunet.org

   Christian Grothoff
   Berner Fachhochschule
   Hoeheweg 80
   CH-2501 Biel/Bienne
   Switzerland

   Email: grothoff@gnunet.org

   Bernd Fix
   GNUnet e.V.
   Boltzmannstrasse 3
   85748 Garching
   Germany

   Email: fix@gnunet.org

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