Research of digital signature based on SHA-1 and RSA in official document transmission

The digital signature provides effective measures for the security of official document transmission, but until now there hasn’t a perfect proposal to solve the digital signature of official document transmission. According the characteristic of official document transmission, the arithmetic of SHA-1 and RSA is introduced, and a more perfect proposal of official document digital signature is proposed. This proposal can perfectly guarantee the privacy of official document, and security of transmission on the Internet. The modifying and replacing are validly prevented by other people during the transmission of official document to ensure the authenticity of documents.