feat: make PresignatureId be generated and reproducible from triple i…

…ds (#752)

* Make PresignatureId be generated from triple ids

* Use the first 8 bytes instead

chain-signatures/node/Cargo.toml

@@ -33,6 +33,7 @@ rand = "0.8"
 reqwest = { version = "0.11.16", features = ["blocking", "json"] }
 semver = "1.0.23"
 sha2 = "0.10.8"
+sha3 = "0.10.8"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 thiserror = "1"

chain-signatures/node/src/protocol/mod.rs

@@ -1,11 +1,11 @@
 mod cryptography;
-mod signature;
 
 pub mod consensus;
 pub mod contract;
 pub mod message;
 pub mod monitor;
 pub mod presignature;
+pub mod signature;
 pub mod state;
 pub mod triple;
 

chain-signatures/node/src/protocol/presignature.rs

@@ -10,6 +10,7 @@ use chrono::Utc;
 use crypto_shared::PublicKey;
 use k256::Secp256k1;
 use mpc_contract::config::ProtocolConfig;
+use sha3::{Digest, Sha3_256};
 use std::collections::hash_map::Entry;
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::time::{Duration, Instant};
@@ -213,7 +214,7 @@ impl PresignatureManager {
         private_share: &SecretKeyShare,
         timeout: u64,
     ) -> Result<(), InitializationError> {
-        let id = rand::random();
+        let id = hash_as_id(triple0.id, triple1.id);
 
         // Check if the `id` is already in the system. Error out and have the next cycle try again.
         if self.generators.contains_key(&id)
@@ -516,3 +517,23 @@ impl PresignatureManager {
         messages
     }
 }
+
+pub fn hash_as_id(triple0: TripleId, triple1: TripleId) -> PresignatureId {
+    let mut hasher = Sha3_256::new();
+    hasher.update(triple0.to_le_bytes());
+    hasher.update(triple1.to_le_bytes());
+    let id: [u8; 32] = hasher.finalize().into();
+    let id = u64::from_le_bytes(first_8_bytes(id));
+
+    PresignatureId::from(id)
+}
+
+const fn first_8_bytes(input: [u8; 32]) -> [u8; 8] {
+    let mut output = [0u8; 8];
+    let mut i = 0;
+    while i < 8 {
+        output[i] = input[i];
+        i += 1;
+    }
+    output
+}