Add validation for participant selection in coordinator demo (#48)

coordinator/src/step_1.rs

@@ -16,39 +16,56 @@ pub fn step_1(reader: &mut impl BufRead, logger: &mut dyn Write) -> Participants
     participants
 }
 
+fn validate(
+    id: Identifier,
+    key_package: PublicKeyPackage,
+    id_list: &[Identifier],
+) -> Result<(), Error> {
+    if key_package.signer_pubkeys().contains_key(&id) {
+        return Err(Error::DuplicatedIdentifier);
+    }; // TODO: Error is actually that the identifier does not exist
+    if !id_list.contains(&id) {
+        return Err(Error::DuplicatedIdentifier);
+    };
+    Ok(())
+}
+
 // TODO: validate min num of participants
 // TODO: validate participant must exist
 
 // Input required:
 // 1. public key package
-// 2. number of signparticipantsers
-// 3. identifiers for all signers
+// 2. number of participants
+// 3. identifiers for all participants
 fn choose_participants(
     input: &mut impl BufRead,
     logger: &mut dyn Write,
 ) -> Result<ParticipantsConfig, Error> {
     writeln!(logger, "Paste the JSON public key package: ").unwrap();
     let mut key_package = String::new();
     input.read_line(&mut key_package).unwrap();
-    let pub_key_package = serde_json::from_str(&key_package).unwrap();
+    let pub_key_package: PublicKeyPackage = serde_json::from_str(&key_package).unwrap();
 
-    //TODO: validate for unique identifiers
     writeln!(logger, "The number of participants: ").unwrap();
 
-    let mut signers = String::new();
-    input.read_line(&mut signers).unwrap();
-    let num_of_signers = signers.trim().parse::<u16>().unwrap();
+    let mut participants = String::new();
+    input.read_line(&mut participants).unwrap();
+    let num_of_participants = participants.trim().parse::<u16>().unwrap();
 
     let mut participants = Vec::new();
 
-    for i in 1..=num_of_signers {
+    for i in 1..=num_of_participants {
+        let package = pub_key_package.clone();
         writeln!(logger, "Identifier for participant {:?} (hex encoded):", i).unwrap();
 
         let mut identifier_input = String::new();
 
         input.read_line(&mut identifier_input).unwrap();
 
         let id_value = serde_json::from_str(&identifier_input).unwrap();
+
+        validate(id_value, package, &participants)?;
+
         participants.push(id_value)
     }
     Ok(ParticipantsConfig {

coordinator/src/tests/steps.rs

@@ -91,8 +91,6 @@ fn check_step_3() {
 
     let signing_package = SigningPackage::new(signing_commitments, b"test");
 
-    // expect group sig: "72c948a63797c693e8e978fdb703a1f5a7590472a539da13b71dd6c2b8c1b2a664b7b4af6194439357c5d15f366760fce53c985a186709e74bb0f8e5078ea805"
-
     step_3(
         &mut valid_input,
         &mut buf,