Contract text protection method based on RSA encryption sha-256 digital signature

The invention discloses a contract text protection method based on RSA encrypted sha-256 digital signature. The method comprises the following steps: 1) obtaining to-be-sent contract text original data; 2) encrypting the original contract text data by using a sha-256 algorithm to generate a signature file; 3) adding a timestamp to the signature file which is encrypted for the first time, and performing encrypting again in combination with the RSA private key of the sender to generate a digital signature; 4) storing the generated digital signature in a data head for network transmission; 5) performing decrypting by using the RSA public key of the sender, acquiring data by the receiver, performing user identity authentication in combination with a timestamp, and obtaining a sha-256 digital signature abstract; 6) carrying out sha-256 signature on the original contract text to calculate an abstract; (7) comparing and verifying whether the calculated abstract is consistent with a decryptedsignature abstract or not