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Diffstat (limited to 'doc/api.md')
| -rw-r--r-- | doc/api.md | 18 |
1 files changed, 5 insertions, 13 deletions
@@ -93,21 +93,13 @@ an [attack](https://git.sigsum.org/sigsum/tree/archive/2021-08-10-witnessing-bro in multi-log ecosystems. #### 2.3.2 - (Co)signed tree head -A signed tree head contains a tree head and a signature. -``` -struct signed_tree_head { - struct tree_head tree_head; - u8 signature[64]; -}; -``` - -`tree_head` describes a log's state, see Section 2.3.1. +A signed tree head is composed of a tree head and a signature. This structure +does not have a Trunnel definition because it is neither signed nor logged. -`signature` is a log's signature over `tree_head`. +Logs and witnesses sign the same `tree_head` structure, see Section 2.3.1. -A witness cosigns the same serialized _tree head_. Note that tree heads are -scoped to a specific log to ensure that a witness signature for log X cannot be -confused with a witness signature for log Y. +Note that tree heads are scoped to a specific log to ensure that a witness +signature for log X cannot be confused with a witness signature for log Y. A witness must not cosign a tree head if it is inconsistent with prior history or if the timestamp is backdated more than 5 minutes. A witness can be viewed |