According to the query of CSDN blog, digital signature uses public key encryption algorithm and private key signature technology to sign data, and its security depends on the difficulty of mathematical problems. By using public key encryption algorithm and private key signature technology, the integrity and non-repudiation of the message can be guaranteed. In digital signature, the sender uses the private key to sign the message, and the receiver uses the public key to verify the signature and extract the message. If the attacker tries to modify the message, the signature verification will fail, thus ensuring the integrity and authenticity of the message.