Handle error for group public key (#18)

Update group_public_key field in config to use VerifyingKey type

participant/src/lib.rs

@@ -1,4 +1,4 @@
-use frost::{Error, Identifier};
+use frost::{Error, Identifier, VerifyingKey};
 use frost_ed25519 as frost;
 use hex::FromHex;
 use std::io::BufRead;
@@ -7,7 +7,7 @@ use std::io::BufRead;
 pub struct Config {
     pub identifier: Identifier,
     pub public_key: [u8; 32],
-    pub group_public_key: [u8; 32],
+    pub group_public_key: VerifyingKey,
 }
 
 pub trait Logger {
@@ -41,7 +41,8 @@ pub fn request_inputs(input: &mut impl BufRead, logger: &mut dyn Logger) -> Resu
 
     input.read_line(&mut group_public_key_input).unwrap();
 
-    let group_public_key = <[u8; 32]>::from_hex(group_public_key_input.trim()).unwrap();
+    let group_public_key = VerifyingKey::from_hex(group_public_key_input.trim())
+        .map_err(|_| Error::MalformedVerifyingKey)?; // TODO: Frost library needs to be updated with correct Error type
 
     Ok(Config {
         identifier: Identifier::try_from(identifier)?,

participant/src/tests/lib.rs

@@ -1,3 +1,4 @@
+use frost::VerifyingKey;
 #[cfg(test)]
 use frost::{Error, Identifier};
 use frost_ed25519 as frost;
@@ -21,7 +22,7 @@ fn check_valid_inputs() {
             .unwrap();
     let identifier = Identifier::try_from(1).unwrap();
     let group_public_key =
-        <[u8; 32]>::from_hex("15d21ccd7ee42959562fc8aa63224c8851fb3ec85a3faf66040d380fb9738673")
+        VerifyingKey::from_hex("15d21ccd7ee42959562fc8aa63224c8851fb3ec85a3faf66040d380fb9738673")
             .unwrap();
 
     let config = Config {
@@ -83,3 +84,19 @@ fn check_invalid_length_public_key() {
     assert!(expected.is_err());
     assert!(expected == Err(Error::MalformedVerifyingKey))
 }
+
+#[test]
+fn check_invalid_length_group_public_key() {
+    let mut test_logger = TestLogger(Vec::new());
+
+    let identifier = "1";
+    let pub_key = "929dcc590407aae7d388761cddb0c0db6f5627aea8e217f4a033f2ec83d93509";
+    let group_pub_key = "123456";
+    let input = format!("{}\n{}\n{}\n", identifier, pub_key, group_pub_key);
+    let mut invalid_input = input.as_bytes();
+
+    let expected = request_inputs(&mut invalid_input, &mut test_logger);
+
+    assert!(expected.is_err());
+    assert!(expected == Err(Error::MalformedVerifyingKey))
+}