As one of the important means to maintain the security of data information, digital signature can solve the problems of forgery, denial, counterfeiting and tampering. Its main functions are embodied in the following aspects:

Counterfeiting Others can't forge the signature of the message, because the private key is only known to the signer, so others can't construct the correct signature result data.

Tamper proof The digital signature is sent to the receiver together with the original file or abstract. Once the information is tampered with, the receiver can judge that the file is invalid by calculating the abstract and verifying the signature, thus ensuring the integrity of the file.

Prevent denial. Digital signature can be used not only as the basis of identity authentication, but also as evidence of signer's signature operation. In order to prevent the receiver from denying it, the digital signature system can require the receiver to return his signed message to the sender or a trusted third party. If the receiver does not return any message, the communication can be terminated or restarted, and the signer has no loss, and neither party can deny it.

Keep it secret. Once the handwritten signature file is lost, the file information is likely to be leaked, but the digital signature can encrypt the message to be signed. In network transmission, the message can be encrypted with the public key of the receiver to ensure the confidentiality of the information.

Identity authentication. In digital signature, the customer's public key is a sign of his identity. When signing with a private key, if the receiver or verifier passes the verification with his own public key, then it can be determined that the signer is the one who owns the private key, because only the signer knows the private key.