Digital signature technology is a typical application of asymmetric encryption algorithm. The application process of digital signature is that the sender of the data source encrypts the data checksum or other variables related to the data content with his own private key to complete the legal "signature" of the data, and the receiver of the data interprets the received "digital signature" with the public key of the other party, and uses the interpretation result to check the integrity of the data to confirm the legality of the signature. Digital signature technology is an important technology to confirm identity in the virtual environment of network system, which can completely replace the "autograph" in the real process and get technical and legal protection. In the management of public and private keys, the application of digital signature is just the opposite of PGP technology for encrypting emails. In the application of digital signature, the sender's public key is easy to obtain, but his private key needs to be kept strictly confidential. Digital signature includes general digital signature and special digital signature. Common digital signature algorithms include RSA, ElGmal, Fiat-Shamir, Guillou-quiqour, Schnorr, Ong-Schnorr-Shamir, Des/DSA, elliptic curve digital signature algorithm and finite automaton digital signature algorithm. Special digital signatures include blind signature, proxy signature, group signature, undeniable signature, fair blind signature, threshold signature, signature with message recovery function and so on. It is closely related to the specific application environment.