First draft of key resharing protocol

CHANGELOG.md

@@ -4,6 +4,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [0.2.0] - In development
+
+### Added
+
+- A basic implementation of threshold key resharing protocol. ([#96])
+
+
+[#96]: https://github.com/entropyxyz/synedrion/pull/96
+
+
 ## [0.1.0] - 2023-12-07
 
 Initial release.

synedrion/src/cggmp21/protocols.rs

@@ -4,6 +4,7 @@ pub(crate) mod interactive_signing;
 pub(crate) mod key_gen;
 pub(crate) mod key_init;
 pub(crate) mod key_refresh;
+pub(crate) mod key_resharing;
 pub(crate) mod presigning;
 pub(crate) mod signing;
 mod threshold;

synedrion/src/cggmp21/protocols/generic.rs

@@ -126,6 +126,7 @@ pub(crate) enum FinalizationRequirement {
     AllBroadcasts,
     AllDms,
     AllBroadcastsAndDms,
+    Custom,
 }
 
 pub(crate) trait Finalizable: BroadcastRound + DirectRound {
@@ -150,6 +151,7 @@ pub(crate) trait Finalizable: BroadcastRound + DirectRound {
                     && contains_all_except(dm_payloads, self.num_parties(), self.party_idx())
                     && contains_all_except(dm_artifacts, self.num_parties(), self.party_idx())
             }
+            FinalizationRequirement::Custom => panic!("`can_finalize` must be implemented"),
         }
     }
 
@@ -188,6 +190,7 @@ pub(crate) trait Finalizable: BroadcastRound + DirectRound {
                 ));
                 missing
             }
+            FinalizationRequirement::Custom => panic!("`missing_payloads` must be implemented"),
         }
     }
 }