1. First, both parties need to generate a pair of keys, including a public key and a private key. The public key can be made public, while the private key needs to be kept secret.

2. Then, the authenticator exchanges public keys or other public information to establish a * * * shared key. This process can be performed by encrypted communication or other security means.

3. Secondly, both parties sign the information with their own private keys and send the signed information to each other. The receiver can use the public key of the other party to verify the validity of the signature. If the signature is valid, the authentication is successful.

Finally, digital signature is a technology used to verify the integrity and source of information. The sender uses the private key to sign the information, and the receiver uses the public key to verify the signature. If the signature is valid, it means that the information has not been tampered with and was sent by the sender who owns the private key.