public boolean validatePrepare(final SignedData<PreparePayload> msg) {
    final String msgType = "Prepare";

    if (!isMessageForCurrentRoundFromValidatorAndProposalAvailable(msg, msgType)) {
      return false;
    }

    if (msg.getAuthor().equals(expectedProposer)) {
      LOG.info("Illegal Prepare message; was sent by the round's proposer.");
      return false;
    }

    return validateDigestMatchesProposal(msg.getPayload().getDigest(), msgType);
  }
Validate prepare.

@param msg the msg
@return the boolean
consensus/ibft/src/main/java/org/hyperledger/besu/consensus/ibft/validation/SignedDataValidator.java