change create_new_session to not require specific signers

server/src/functions.rs

@@ -25,7 +25,7 @@ pub(crate) async fn create_new_session(
     // Create new session object.
     let id = Uuid::new_v4();
     let session = Session {
-        identifiers: args.identifiers.iter().cloned().collect(),
+        num_signers: args.num_signers,
         message_count: args.message_count,
         state: SessionState::WaitingForCommitments {
             commitments: Default::default(),
@@ -50,7 +50,7 @@ pub(crate) async fn get_session_info(
     ))?;
 
     Ok(Json(GetSessionInfoOutput {
-        identifiers: session.identifiers.iter().copied().collect(),
+        num_signers: session.num_signers,
         message_count: session.message_count,
     }))
 }
@@ -74,9 +74,6 @@ pub(crate) async fn send_commitments(
 
     match &mut session.state {
         SessionState::WaitingForCommitments { commitments } => {
-            if !session.identifiers.contains(&args.identifier) {
-                return Err(AppError(StatusCode::NOT_FOUND, eyre!("invalid identifier")));
-            }
             if args.commitments.len() != session.message_count as usize {
                 return Err(AppError(
                     StatusCode::INTERNAL_SERVER_ERROR,
@@ -89,7 +86,7 @@ pub(crate) async fn send_commitments(
             // poor networking connectivity leading to retries)
             commitments.insert(args.identifier, args.commitments);
             // If complete, advance to next state
-            if commitments.keys().cloned().collect::<BTreeSet<_>>() == session.identifiers {
+            if commitments.len() == session.num_signers as usize {
                 session.state = SessionState::CommitmentsReady {
                     commitments: commitments.clone(),
                 }
@@ -154,7 +151,7 @@ pub(crate) async fn send_signing_package(
         ))?;
 
     match &mut session.state {
-        SessionState::CommitmentsReady { .. } => {
+        SessionState::CommitmentsReady { commitments } => {
             if args.signing_package.len() != session.message_count as usize
                 || args.randomizer.len() != session.message_count as usize
             {
@@ -164,6 +161,7 @@ pub(crate) async fn send_signing_package(
                 ));
             }
             session.state = SessionState::WaitingForSignatureShares {
+                identifiers: commitments.keys().cloned().collect(),
                 signing_package: args.signing_package,
                 signature_shares: Default::default(),
                 randomizer: args.randomizer,
@@ -194,6 +192,7 @@ pub(crate) async fn get_signing_package(
 
     match &session.state {
         SessionState::WaitingForSignatureShares {
+            identifiers: _,
             signing_package,
             signature_shares: _,
             randomizer,
@@ -228,12 +227,13 @@ pub(crate) async fn send_signature_share(
 
     match &mut session.state {
         SessionState::WaitingForSignatureShares {
+            identifiers,
             signing_package: _,
             signature_shares,
             randomizer: _,
             aux_msg: _,
         } => {
-            if !session.identifiers.contains(&args.identifier) {
+            if !identifiers.contains(&args.identifier) {
                 return Err(AppError(StatusCode::NOT_FOUND, eyre!("invalid identifier")));
             }
             if args.signature_share.len() != session.message_count as usize {
@@ -247,7 +247,7 @@ pub(crate) async fn send_signature_share(
             // poor networking connectivity leading to retries)
             signature_shares.insert(args.identifier, args.signature_share);
             // If complete, advance to next state
-            if signature_shares.keys().cloned().collect::<BTreeSet<_>>() == session.identifiers {
+            if signature_shares.keys().cloned().collect::<BTreeSet<_>>() == *identifiers {
                 session.state = SessionState::SignatureSharesReady {
                     signature_shares: signature_shares.clone(),
                 };

server/src/state.rs

@@ -24,6 +24,9 @@ pub enum SessionState {
     /// SigningPackage ready to be fetched by participants. Waiting for
     /// participants to send their signature shares.
     WaitingForSignatureShares {
+        /// Identifiers of the participants that sent commitments in the
+        /// previous state.
+        identifiers: BTreeSet<frost::Identifier>,
         /// SigningPackage sent by the coordinator to be sent to participants,
         /// for each message being signed.
         signing_package: Vec<frost::SigningPackage>,
@@ -56,8 +59,10 @@ impl Default for SessionState {
 
 /// A particular signing session.
 pub struct Session {
+    /// The number of signers in the session.
+    pub(crate) num_signers: u16,
     /// The set of identifiers for the session.
-    pub(crate) identifiers: BTreeSet<frost::Identifier>,
+    // pub(crate) identifiers: BTreeSet<frost::Identifier>,
     /// The number of messages being simultaneously signed.
     pub(crate) message_count: u8,
     /// The session state.

server/src/types.rs

@@ -7,7 +7,7 @@ use reddsa::frost::redpallas as frost;
 
 #[derive(Serialize, Deserialize)]
 pub struct CreateNewSessionArgs {
-    pub identifiers: Vec<frost::Identifier>,
+    pub num_signers: u16,
     pub message_count: u8,
 }
 
@@ -23,7 +23,7 @@ pub struct GetSessionInfoArgs {
 
 #[derive(Serialize, Deserialize)]
 pub struct GetSessionInfoOutput {
-    pub identifiers: Vec<frost::Identifier>,
+    pub num_signers: u16,
     pub message_count: u8,
 }
 

server/tests/integration_tests.rs

@@ -38,7 +38,7 @@ async fn test_main_router() -> Result<(), Box<dyn std::error::Error>> {
     let res = server
         .post("/create_new_session")
         .json(&server::CreateNewSessionArgs {
-            identifiers: key_packages.keys().copied().collect::<Vec<_>>(),
+            num_signers: 2,
             message_count: 2,
         })
         .await;
@@ -51,7 +51,7 @@ async fn test_main_router() -> Result<(), Box<dyn std::error::Error>> {
 
     // Map to store the SigningNonces (for each message, for each participant)
     let mut nonces_map = BTreeMap::<_, _>::new();
-    for (identifier, key_package) in key_packages.iter() {
+    for (identifier, key_package) in key_packages.iter().take(2) {
         // As participant `identifier`
 
         // Get the number of messages (the participants wouldn't know without
@@ -85,7 +85,9 @@ async fn test_main_router() -> Result<(), Box<dyn std::error::Error>> {
                 commitments: commitments_vec,
             })
             .await;
-        res.assert_status_ok();
+        if res.status_code() != 200 {
+            panic!("status code: {}; error: {}", res.status_code(), res.text());
+        }
     }
 
     // As the coordinator, get the commitments
@@ -127,7 +129,7 @@ async fn test_main_router() -> Result<(), Box<dyn std::error::Error>> {
 
     // As each participant, get SigningPackages and generate the SignatureShares
     // for each.
-    for (identifier, key_package) in key_packages.iter() {
+    for (identifier, key_package) in key_packages.iter().take(2) {
         // As participant `identifier`
 
         // Get SigningPackages
@@ -201,21 +203,6 @@ async fn test_main_router() -> Result<(), Box<dyn std::error::Error>> {
 /// A better example on how to write client code.
 #[tokio::test]
 async fn test_http() -> Result<(), Box<dyn std::error::Error>> {
-    // Create test values
-    let mut rng = thread_rng();
-    let (shares, _pubkeys) =
-        frost::keys::generate_with_dealer(3, 2, frost::keys::IdentifierList::Default, &mut rng)
-            .unwrap();
-    let key_packages: BTreeMap<_, _> = shares
-        .iter()
-        .map(|(identifier, secret_share)| {
-            (
-                *identifier,
-                frost::keys::KeyPackage::try_from(secret_share.clone()).unwrap(),
-            )
-        })
-        .collect();
-
     // Spawn server for testing
     tokio::spawn(async move {
         server::run(&Args {
@@ -235,7 +222,7 @@ async fn test_http() -> Result<(), Box<dyn std::error::Error>> {
     let r = client
         .post("http://127.0.0.1:2744/create_new_session")
         .json(&server::CreateNewSessionArgs {
-            identifiers: key_packages.keys().copied().collect::<Vec<_>>(),
+            num_signers: 2,
             message_count: 1,
         })
         .send()