diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/design.md | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/doc/design.md b/doc/design.md index 5d23df8..87e95ca 100644 --- a/doc/design.md +++ b/doc/design.md @@ -119,13 +119,11 @@ The only supported hash function is SHA256. Not having any cryptographic agility makes protocols and data formats simpler and more secure. - **Simple (de)serialization parsers:** complex (de)serialization parsers increase attack surfaces and make the system more difficult to use in -constrained environments. A claimant's sigsum statements can be (de)serialized using +constrained environments. A sigsum statement can be (de)serialized using [Trunnel](https://gitlab.torproject.org/tpo/core/trunnel/-/blob/main/doc/trunnel.md), -or "by hand" in many modern programming languages. -A sigsum log's statements are serialized as line-terminated ASCII -[\[Checkpoint\]](). -A sigsum log's HTTP(S) API uses line-terminated ASCII [\[SigsumAPI\]](). -The required parsing is easy to implement without too much trouble or dependencies. +or "by hand" in many modern programming languages. This is the only parsing +that a believer is required to support. Claimants and verifiers additionally +need to interact with a sigsum log's HTTP(S) API with line-terminated ASCII. ### 1.4 - Roadmap First we describe our threat model. Then we give a bird's view of the design. @@ -279,16 +277,16 @@ using the same mechanism as the opaque data. A believer receives: 1. **Opaque data**: a claimant's opaque data. 2. **Shard hint**: a claimant's selected shard hint. 3. **Signature**: a claimant's signed statement. -4. **Checkpoint**: a log's signed tree head and a list of cosignatures +4. **(Co)signed tree head**: a log's signed tree head and a list of cosignatures from so-called _witnesses_. 5. **Inclusion proof**: a proof of inclusion that is based on the logged leaf -and the above checkpoint. +and the above tree head. Ideally, a believer should only accept the opaque data if these criteria hold: - The claimant's signed statement verifies. - The log's tree head can be reconstructed from the logged leaf and the provided inclusion proof. -- The log's checkpoint has enough valid (co)signatures. +- The log's tree head has enough valid (co)signatures. Notice that there are no new outbound network connections for a believer. Therefore, a proof of public logging is only as convincing as the tree head that @@ -316,7 +314,7 @@ Sigsum logs are sharded and shut down at predefined times. A sigsum log can shut down _safely_ because verification on the believer-side is not interactive. The difficulty of bypassing public logging is based on the difficulty of controlling enough independent witnesses. A witness verifies that a log's -checkpoint is correct before cosigning. +tree head is correct before cosigning. Claimants, verifiers, and witnesses interact with the log using an HTTP(S) API. A claimant must prove that they own a domain name as an anti-spam mechanism. |