English explanation:

Digital signature (not to be confused with digital certificate) is a mathematical technique used to verify the authenticity and integrity of messages, software or digital documents.

General idea:

"Digital signature" (not to be confused with "digital certificate") is a mathematical technique used to verify the authenticity and integrity of mail, software or digital documents.

Chinese background explanation:

Digital signature (also known as public key digital signature and electronic signature) is a digital string that can only be generated by the sender of information, and others cannot forge it. This number string is also an effective proof of the authenticity of the information sent by the information sender.

See Baidu Encyclopedia "Digital Signature" for details.