Merge branch 'design' of github.com:system-transparency/stfe into design

1 files changed, 71 insertions, 0 deletions

diff --git a/doc/claimant.md b/doc/claimant.md
new file mode 100644
index 0000000..6728fef
--- /dev/null
+++ b/doc/claimant.md
@@ -0,0 +1,71 @@
+# Claimant model
+## **System<sup>CHECKSUM</sup>**
+System<sup>CHECKSUM</sup> is about the claims made by a data publisher.
+* **Claim<sup>CHECKSUM</sup>**:
+	_I, data publisher, claim that the data_:
+	1. has cryptographic hash X
+	2. is produced by no-one but myself
+* **Statement<sup>CHECKSUM</sup>**: signed checksum<br>
+* **Claimant<sup>CHECKSUM</sup>**: data publisher<br>
+	The data publisher is a party that wants to publish some data.
+* **Believer<sup>CHECKSUM</sup>**: end-user<br>
+	The end-user is a party that wants to use some published data.
+* **Verifier<sup>CHECKSUM</sup>**: data publisher<br>
+	Only the data publisher can verify the above claims.
+* **Arbiter<sup>CHECKSUM</sup>**:<br>
+    There's no official body.  Invalidated claims would affect reputation.
+
+System<sup>CHECKSUM\*</sup> can be defined to make more specific claims.  Below
+is a reproducible builds example.
+
+### **System<sup>CHECKSUM-RB</sup>**:
+System<sup>CHECKSUM-RB</sup> is about the claims made by a _software publisher_
+that makes reproducible builds available.
+* **Claim<sup>CHECKSUM-RB</sup>**:
+	_I, software publisher, claim that the data_:
+	1. has cryptographic hash X
+	2. is the output of a reproducible build for which the source can be located
+	using X as an identifier
+* **Statement<sup>CHECKSUM-RB</sup>**: Statement<sup>CHECKSUM</sup>
+* **Claimant<sup>CHECKSUM-RB</sup>**: software publisher<br>
+	The software publisher is a party that wants to publish the output of a
+	reproducible build.
+* **Believer<sup>CHECKSUM-RB</sup>**: end-user<br>
+	The end-user is a party that wants to run an executable binary that built
+	reproducibly.
+* **Verifier<sup>CHECKSUM-RB</sup>**: any interested party<br>
+	These parties try to verify the above claims.  For example:
+	* the software publisher itself (_"has my identity been compromised?"_)
+	* rebuilders that check for locatability and reproducibility
+* **Arbiter<sup>CHECKSUM-RB</sup>**:<br>
+    There's no official body.  Invalidated claims would affect reputation.
+
+## **System<sup>CHECKSUM-LOG</sup>**:
+System<sup>CHECKSUM-LOG</sup> is about the claims made by a _log operator_.
+It adds _discoverability_ into System<sup>CHECKSUM\*</sup>.  Discoverability
+means that Verifier<sup>CHECKSUM\*</sup> can see all
+Statement<sup>CHECKSUM</sup> that Believer<sup>CHECKSUM\*</sup> accept.
+
+* **Claim<sup>CHECKSUM-LOG</sup>**:
+	_I, log operator, make available:_
+	1. a globally consistent append-only log of Statement<sup>CHECKSUM</sup>
+* **Statement<sup>CHECKSUM-LOG</sup>**: signed tree head
+* **Claimant<sup>CHECKSUM-LOG</sup>**: log operator<br>
+   Possible operators might be:
+	* a small subset of data publishers
+	* members of relevant consortia
+* **Believer<sup>CHECKSUM-LOG</sup>**:
+	* Believer<sup>CHECKSUM\*</sup>
+	* Verifier<sup>CHECKSUM\*</sup><br>
+* **Verifier<sup>CHECKSUM-LOG</sup>**: third parties<br>
+	These parties verify the above claims.  Examples include:
+	* members of relevant consortia
+	* non-profits and other reputable organizations
+	* security enthusiasts and researchers
+	* log operators (cross-ecosystem)
+	* monitors (cross-ecosystem)
+	* a small subset of data publishers (cross-ecosystem)
+* **Arbiter<sup>CHECKSUM-LOG</sup>**:<br>
+	There is no official body.  The ecosystem at large should stop using an
+	instance of System<sup>CHECKSUM-LOG</sup> if cryptographic proofs of log
+	misbehavior are preseneted by some Verifier<sup>CHECKSUM-LOG</sup>.