From a242308c56b12c132a3212d8bb4fbf502247b328 Mon Sep 17 00:00:00 2001 From: Rasmus Dahlberg Date: Mon, 31 Jan 2022 17:22:45 +0100 Subject: documented decided get-tree-head endpoint proposal Refer to doc/proposals/2022-01-tree-head-endpoint doc/proposals/2022-01-no-quick-tree-head-endpoint for details. --- doc/design.md | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) (limited to 'doc/design.md') diff --git a/doc/design.md b/doc/design.md index d0d62cb..ed972d0 100644 --- a/doc/design.md +++ b/doc/design.md @@ -243,15 +243,16 @@ logs cannot guarantee low latency. The signer needs to wait until the log accepted their request, after which it can be verified using an inclusion proof. #### 3.2.3 - Wait for witness cosigning -Sigsum logs periodically freeze the most current tree head, typically every five -minutes. Cosigning witnesses poll logs for so-called _to-sign_ tree heads and -verify that they are fresh and append-only before doing a cosignature operation. -Cosignatures are posted back to logs so that signers can easily fetch finalized -cosigned tree heads. - -It thus takes five to ten minutes before a signer's distribution phase can start. -The added latency is a trade-off that simplifies sigsum logging by removing the -need for reactive gossip-audit protocols +Cosigning witnesses poll the logs for tree heads to be cosigned once per minute, +verifying that they are fresh (not back-dated more than five minutes) and +append-only (no leaves were removed or modified) before doing any cosignature +operations. Cosignatures are posted back to the logs so that they become +available in one place. + +The above means that it takes up to 5-10 minutes before a cosigned tree head is +available. Depending on implementation it may be as short as one minute. The +added latency is an important trade-off that significantly simplifies sigsum +logging by removing the need for reactive gossip-audit protocols [\[G1,](https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7346853) [G2,](https://datatracker.ietf.org/doc/html/draft-ietf-trans-gossip-05) [G3,](https://petsymposium.org/2021/files/papers/issue2/popets-2021-0024.pdf) -- cgit v1.2.3