Time stamp is a complete and verifiable data, which can represent a piece of data that existed before a certain moment, usually a character sequence that uniquely identifies the time at a certain moment.
The data generated by digital signature technology includes original file information, signature parameters, signature time and other information. Generally speaking, the time stamp is mainly put forward to provide users with an electronic evidence to prove the generation time of some data.
In addition to time stamp technology, "digital signature technology" is also an important means to obtain legal recognition of electronic contracts.
The main way of digital signature is that the sender of the message generates a hash value from the message text. The sender encrypts this hash value with his own private key to form the sender's digital signature. Then, the digital signature will be sent to the recipient of the email as an attachment. The receiver of the message first calculates the hash value from the received original message, and then decrypts and verifies the digital signature attached to the message with the sender's public key. If the two hash values are the same, the receiver can confirm that the digital signature belongs to the sender. The length of hash value is fixed and the operation is irreversible. The hash values of different plaintext are different, but the hash values of the same plaintext are the same and unique. Any change in the original text will change its hash value. Through this principle, we can identify whether the file has been tampered with.
In short, an electronic contract that is tamper-proof and accurately records the signing time is effective.