frost-client: add support for group description (#397)

frost-client/src/args.rs

@@ -67,6 +67,10 @@ pub(crate) enum Command {
         /// dealer process via the FROST server (TODO: this is not supported yet)
         #[arg(short, long)]
         config: Vec<String>,
+        /// A description of the group being created. Will be written to the
+        /// participant's config files and will help them identify groups.
+        #[arg(short, long)]
+        description: String,
         /// The comma-separated name of each participant.
         #[arg(short = 'N', long, value_delimiter = ',')]
         names: Vec<String>,

frost-client/src/config.rs

@@ -57,23 +57,26 @@ pub struct CommunicationKey {
 }
 
 /// A FROST group the user belongs to.
-// TODO: add a textual name for the group?
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct Group {
+    /// A human-readable description of the group to make it easier to select
+    /// groups
+    pub description: String,
+    /// The ciphersuite being used for the group
     pub ciphersuite: String,
     /// The encoded public key package for the group.
     #[serde(
         serialize_with = "serdect::slice::serialize_hex_lower_or_bin",
         deserialize_with = "serdect::slice::deserialize_hex_or_bin_vec"
     )]
     pub public_key_package: Vec<u8>,
-    /// The user's encodede key package for the group.
+    /// The user's encoded key package for the group.
     #[serde(
         serialize_with = "serdect::slice::serialize_hex_lower_or_bin",
         deserialize_with = "serdect::slice::deserialize_hex_or_bin_vec"
     )]
     pub key_package: Vec<u8>,
-    /// The server the participants are registered in, if any.
+    /// The default server the participants are using, if any.
     pub server_url: Option<String>,
     /// The group participants, keyed by hex-encoded identifier
     pub participant: BTreeMap<String, Participant>,
@@ -86,7 +89,8 @@ impl Group {
         let helper = ciphersuite_helper(&self.ciphersuite)?;
         let info = helper.group_info(&self.key_package, &self.public_key_package)?;
         let mut s = format!(
-            "Group with public key {}\nServer URL: {}\nThreshold: {}\nParticipants: {}\n",
+            "Group \"{}\"\nPublic key {}\nServer URL: {}\nThreshold: {}\nParticipants: {}\n",
+            self.description,
             info.hex_verifying_key,
             self.server_url.clone().unwrap_or_default(),
             info.threshold,

frost-client/src/trusted_dealer.rs

@@ -33,6 +33,7 @@ pub(crate) fn trusted_dealer_for_ciphersuite<C: Ciphersuite + MaybeIntoEvenY + '
 ) -> Result<(), Box<dyn Error>> {
     let Command::TrustedDealer {
         config,
+        description,
         ciphersuite: _,
         threshold,
         num_signers,
@@ -91,6 +92,7 @@ pub(crate) fn trusted_dealer_for_ciphersuite<C: Ciphersuite + MaybeIntoEvenY + '
         let key_package: KeyPackage<C> = share.clone().try_into()?;
         let group = Group {
             ciphersuite: C::ID.to_string(),
+            description: description.clone(),
             key_package: postcard::to_allocvec(&key_package)?,
             public_key_package: postcard::to_allocvec(&public_key_package)?,
             participant: participants.clone(),