The messages at these indices were committed to in the commitment and are not revealed to the signer. This is expected to be sorted in ascending order
The commitment to the blinded messages
OptionalrevealedThe messages which are known to the signer. Here the key is message index (as per the MACParams). This is not
mandatory as the signer might already know the messages to sign. This is used when the requester wants to inform the
signer of some or all of the message
Structure to send to the signer to request a blind MAC for BBDT16 scheme.