Because of its directionality, the security of this signature scheme has been strengthened, and the scope of attack and forgery has been greatly reduced.
At present, there are mainly ElGamal signature scheme and MR signature scheme. MR directional signature scheme is a signature scheme with message recovery ability, which was established by Nyberg et al. The difference between them is that when verifying the validity of ElGamal signature, the signer should send the message to the receiver together with the signature. When MR signature is used, there is no need to transmit the message itself. Anyone who receives a signature can use it to recover the message itself. The advantage of using MR signature scheme is that even without encryption scheme, no one can see the content of the message except the receiver. Therefore, MR directional signature scheme is not only a signature scheme, but also plays the role of encrypting messages. [ 1]