frost-client: check if number of randomizers match number of messages

coordinator/src/cli.rs

@@ -34,6 +34,10 @@ pub async fn cli_for_processed_args<C: RandomizedCiphersuite + 'static>(
         Box::new(SocketComms::new(&pargs))
     };
 
+    if !pargs.randomizers.is_empty() && pargs.randomizers.len() != pargs.messages.len() {
+        return Err("Number of randomizers must match number of messages".into());
+    }
+
     let participants_config = step_1(&pargs, &mut *comms, reader, logger).await?;
 
     let signing_package = step_2(&pargs, logger, participants_config.commitments.clone())?;

frost-client/src/args.rs

@@ -175,10 +175,10 @@ pub(crate) enum Command {
         #[arg(short = 'm', long)]
         message: Vec<String>,
         /// The randomizers to use. Each instance can be a file with the raw
-        /// randomizer, "" or "-". If "" or "-" is specified, then it will be read
-        /// from standard input as a hex string. If none are passed, random ones
-        /// will be generated. If one or more are passed, the number should match
-        /// the `message` parameter.
+        /// randomizer, "" or "-". If "" or "-" is specified, then it will be
+        /// read from standard input as a hex string. If none are passed, random
+        /// ones will be generated if the ciphersuite is redpallas. If one or
+        /// more are passed, the number should match the `message` parameter.
         #[arg(short = 'r', long)]
         randomizer: Vec<String>,
         /// Where to write the generated raw bytes signature. If "-", the