Internet Engineering Task Force O. Sury
Internet-Draft CZ.NIC
Intended status: Standards Track R. Edmonds
Expires: March 11, 2016 Farsight Security, Inc.
September 8, 2015
Ed25519 for DNSSEC
draft-sury-dnskey-ed25519-03
Abstract
This document describes how to specify Ed25519 keys and signatures in
DNS Security (DNSSEC). It uses the Ed25519 instance of the Edwards-
curve Digital Signature Algorithm (EdDSA) with the SHA-512 hash
algorithm.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 11, 2016.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. DNSKEY and RRSIG Resource Records for Ed25519 . . . . . . . . 3
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Implementation Status . . . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
DNSSEC, which is broadly defined in [RFC4033], [RFC4034], and
[RFC4035], uses cryptographic keys and digital signatures to provide
authentication of DNS data. Currently, the most popular signature
algorithm in use is RSA. [RFC5933] and [RFC6605] later defined the
use of GOST and NIST specified elliptic curve cryptography in DNSSEC.
This document defines the use of DNSSEC's DS, DNSKEY, and RRSIG
resource records (RRs) with a new signing algorithm: the Ed25519
instance of the Edwards-curve Digital Signature Algorithm (EdDSA)
used with the SHA-512 hash algorithm. A more thorough description of
Ed25519 can be found in [I-D.josefsson-eddsa-ed25519].
Ed25519 has a 128-bit security target, which is considered to be
equivalent in strength to RSA with ~3000-bit keys. Ed25519 public
keys are 256 bits (32 bytes) long while signatures are 512 bits (64
bytes) long.
The usage of the Ed25519 algorithm in DNSSEC has advantages and
disadvantages relative to RSA. Ed25519 keys are much shorter than
RSA keys. At comparable strengths, Ed25519 keys are 352 bytes
smaller than RSA-3072 keys. Similarly, an Ed25519 signature saves
320 bytes over an RSA-3072 signature.
However, DNSSEC with RSA is not commonly deployed on the Internet
with signatures as large as 3072 bits. [RFC6781] contemplates the
routine use of RSA-1024 and RSA-2048 in DNSSEC. Even when compared
to the use of RSA at reduced strengths, Ed25519 still provides
substantially smaller keys and signatures.
Signing with Ed25519 is significantly faster than signing with
equivalently strong RSA, and it is also faster than signing with the
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existing ECDSA algorithms defined in [RFC6605]. However, the
validation of RSA signatures is significantly faster than the
validation of Ed25519 signatures.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. DNSKEY and RRSIG Resource Records for Ed25519
An Ed25519 public key consists of a 32-byte value that represents the
compressed encoding of the curve point, which is encoded into the
Public Key field of a DNSKEY resource record as a simple bit string.
The generation of a public key is defined in Chapter 5.5 in
[I-D.josefsson-eddsa-ed25519].
An Ed25519 signature consists of a 64-byte value, which is encoded
into the Signature field of an RRSIG resource record as a simple bit
string. The Ed25519 signature algorithm is described in Chapter 5.6
in [I-D.josefsson-eddsa-ed25519].
The algorithm number associated with the use of Ed25519 with SHA-512
in DS, DNSKEY and RRSIG resource records is TBD. This registration
is fully defined in the IANA Considerations section.
4. Examples
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This section needs an update after the algorithm for Ed25519 is
assigned.
Private-key-format: v1.2
Algorithm: TBD (ED25519SHA512)
PrivateKey: ODIyNjAzODQ2MjgwODAxMjI2NDUxOTAyMDQxNDIyNjI=
# corresponding to 82260384628080122645190204142262 INT
example.com. 3600 IN DNSKEY 257 3 TBD (
l02Woi0iS8Aa25FQkUd9RMzZHJpBoRQwAQEX1SxZJA4= )
example.com. 3600 IN DS 3613 TBD 2 (
3aa5ab37efce57f737fc1627013fee07bdf241bd10f3
b1964ab55c78e79a304b )
www.example.com. 3600 IN A 192.0.2.1
www.example.com. 3600 IN RRSIG A TBD 3 3600 (
20150820000000 20150730000000 3613 example.com.
cvTRVrU7dwnemQuBq9/E4tlIiRpvWcEmYdzqs6SCQxw6
qmczBBQGldssMx1TCJnwsEs9ZuA2phPzuJNoon9BCA== )
Private-key-format: v1.2
Algorithm: TBD (ED25519SHA512)
PrivateKey: DSSF3o0s0f+ElWzj9E/Osxw8hLpk55chkmx0LYN5WiY=
example.com. 3600 IN DNSKEY 257 3 TBD (
zPnZ/QwEe7S8C5SPz2OfS5RR40ATk2/rYnE9xHIEijs= )
example.com. 3600 IN DS 55648 TBD 2 (
96401675bc7ecdd541ec0f70d69238c7b95d3bd4de1e
231a068ceb214d02a4ed )
www.example.com. 3600 IN A 192.0.2.1
www.example.com. 3600 IN RRSIG A TBD 3 3600 (
20150820000000 20150730000000 35452 example.com.
yuGb9rCNIuhDaRJbuhYHj89Y/3Pi8KWUm7lOt00ivVRGvgulmVX8DgpE
AFyMP2MKXJrqYJr+ViiCIDwcOIbPAQ==)
5. Acknowledgements
Some of the material in this document is copied liberally from
[RFC6605].
The authors of this document wish to thank Jan Vcelak, Pieter Lexis
and Kees Monshouwer for a review of this document.
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6. IANA Considerations
This document updates the IANA registry "Domain Name System Security
(DNSSEC) Algorithm Numbers". The following entry has been added to
the registry:
+--------------+----------------------+
| Number | TBD |
| Description | Ed25519 with SHA-512 |
| Mnemonic | ED25519SHA512 |
| Zone Signing | Y |
| Trans. Sec. | * |
| Reference | This document |
+--------------+----------------------+
* There has been no determination of standardization of the use of
this algorithm with Transaction Security.
7. Implementation Status
(Note to the RFC Editor: please remove this entire section as well as
the reference to RFC 6982 before publication.)
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC6982].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC6982], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
TODO: Fill out this section.
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8. Security Considerations
Ed25519 is targeted to provide attack resistance comparable to
quality 128-bit symmetric ciphers. Such an assessment could, of
course, change in the future if new attacks that work better than the
ones known today are found.
9. References
9.1. Normative References
[I-D.josefsson-eddsa-ed25519]
Josefsson, S. and N. Moller, "EdDSA and Ed25519", draft-
josefsson-eddsa-ed25519-03 (work in progress), May 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[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,
<http://www.rfc-editor.org/info/rfc4033>.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<http://www.rfc-editor.org/info/rfc4034>.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<http://www.rfc-editor.org/info/rfc4035>.
9.2. Informative References
[RFC5933] Dolmatov, V., Ed., Chuprina, A., and I. Ustinov, "Use of
GOST Signature Algorithms in DNSKEY and RRSIG Resource
Records for DNSSEC", RFC 5933, DOI 10.17487/RFC5933, July
2010, <http://www.rfc-editor.org/info/rfc5933>.
[RFC6605] Hoffman, P. and W. Wijngaards, "Elliptic Curve Digital
Signature Algorithm (DSA) for DNSSEC", RFC 6605, DOI
10.17487/RFC6605, April 2012,
<http://www.rfc-editor.org/info/rfc6605>.
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[RFC6781] Kolkman, O., Mekking, W., and R. Gieben, "DNSSEC
Operational Practices, Version 2", RFC 6781, DOI 10.17487/
RFC6781, December 2012,
<http://www.rfc-editor.org/info/rfc6781>.
[RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", RFC 6982, DOI
10.17487/RFC6982, July 2013,
<http://www.rfc-editor.org/info/rfc6982>.
Authors' Addresses
Ondrej Sury
CZ.NIC
Milesovska 1136/5
Praha 130 00
CZ
Phone: +420 222 745 111
Email: ondrej.sury@nic.cz
Robert Edmonds
Farsight Security, Inc.
155 Bovet Rd #476
San Mateo, California 94402
US
Phone: +1 650 489 7919
Email: edmonds@fsi.io
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