Digital signature algorithm can be regarded as a message digest algorithm with a key (public key+private key), that is, the data signature algorithm is a combination of asymmetric encryption algorithm and message digest algorithm. The algorithm includes two operations: signature and verification, and follows the signature/verification mode of "private key signature and public key verification".

1. Party A constructs a key pair and can issue the public key to Party B. ..

2. Party A wants Party B to send data with additional signature.

3. Party B uses the public key and signature to verify the data.

RSA digital signature algorithms can be divided into MD and SHA. The public key of this algorithm is usually shorter than the private key.

Example of RSA digital signature:

On the implementation level, it can be considered that DSA algorithm implementation is a simplified version of RSA algorithm implementation. DSA algorithm only supports SHA series message digest algorithm.

Example of DSA digital signature:

Compared with the traditional signature algorithm, ECDSA algorithm has the advantages of high speed, high strength and short signature. This algorithm is used to verify the serial numbers of Microsoft operating system and office software.

Example of ECDSA algorithm: