message: Added length check for proposal hash
diff: @@ -181,6 +181,10 @@ impl TryFrom<TxnIDParamsMultisig> for multisig::TxnIDParams {
  let proposal_hash = base64::decode(params.proposal_hash_data)
  .map_err(|err| SignerError::GenericString(err.to_string()))?;
  + if proposal_hash.len() != 32 {
  + return Err(SignerError::GenericString("Invalid proposal_hash length (should 32 bytes).".to_string()));
  + }
  +
  Ok(multisig::TxnIDParams {
  id: multisig::TxnID(params.txn_id),
  proposal_hash,
  