Roughtime Ecosystem
draft-ietf-ntp-roughtime-ecosystem-00
Internet Engineering Task Force W. Ladd
Internet-Draft Cloudflare
Intended status: Informational M. Dansarie
Expires: August 25, 2021 February 21, 2021
Roughtime Ecosystem
draft-ietf-ntp-roughtime-ecosystem-00
Abstract
This document specifies the roles of Roughtime validators, clients,
and servers in providing a ecosystem for secure time.
Status of This Memo
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This Internet-Draft will expire on August 25, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Chaining in roughtime . . . . . . . . . . . . . . . . . . . . 2
3. Impeachement . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Serialization of chains . . . . . . . . . . . . . . . . . . . 3
5. Submission API . . . . . . . . . . . . . . . . . . . . . . . 3
6. Viewing Reports . . . . . . . . . . . . . . . . . . . . . . . 3
7. Trust Anchors and Policies . . . . . . . . . . . . . . . . . 3
8. Normative References . . . . . . . . . . . . . . . . . . . . 3
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 3
1. Introduction
The Roughtime protocol enables servers to provide cryptographic proof
of the times requests were made. This enables clients to expose
cheating by servers. This document describes how these proofs are
seralized and verified, as well as APIs to access and submit reports
of malfeasnce in an automated manner.
2. Chaining in roughtime
Two responses are chained if the NONC field of the second is SHA-
512(blinder || first) where blinder is a 64 byte value. Blinder MUST
be generated uniformly at random to prevent tracking. The first
response is serialized as a roughtime message. The first response is
chained to the second.
A chain is a sequence of messages where each message is chained to
the one before. Every contiguous subsequence of a chain is a chain.
3. Impeachement
For each index i, let m_i denote the timestamp of the response, r_i
the radius around it. Then we have m_i-r_i the earliest actual time
at which the response could have been generated, and m_i+r_i the
latest actual time at which the response could have been generated.
If all requests are generated honestly m_i+r_i < m_{i+j}-r_{i+j}
holds for all indices i and positive numbers j. A failure of this
relation to hold demonstrates that at least one of the responses was
generated incorrectly.
The more distinct servers and responses that are mutually consistent
except for the questionable response, the more likey a failure of the
generator of the errneous response is.
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4. Serialization of chains
TODO
5. Submission API
6. Viewing Reports
7. Trust Anchors and Policies
A trust anchor is any distributor of a list of trusted servers. It
is RECOMMENDED that trust anchors subscribe to a common public forum
where evidence of malfeasance may be shared and discussed. Trust
anchors SHOULD subscribe to a zero-tolerance policy: any generation
of incorrect timestamps will result in removal. To enable this trust
anchors SHOULD list a wide variety of servers so the removal of a
server does not result in operational issues for clients. Clients
SHOULD attempt to detect malfeasance and report it as discussed in
this document.
Because only a single Roughtime server is required for successful
synchronization, Roughtime does not have the incentive problems that
have prevented effective enforcement of discipline on the web PKI.
8. Normative References
[I-D.ietf-ntp-roughtime]
Malhotra, A., Langley, A., and W. Ladd, "Roughtime",
draft-ietf-ntp-roughtime-03 (work in progress), August
2020.
Authors' Addresses
Watson Ladd
Cloudflare
101 Townsend St
San Francisco
USA
Email: watsonbladd@gmail.com
Marcus Dansarie
Sweden
Email: marcus@dansarie.se
URI: https://orcid.org/0000-0001-9246-0263
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