1. key pair generation: DSA needs to use a pair of keys, one of which is the private key and the other is the public key. This pair of keys needs to be generated in a secure way to ensure their security and confidentiality.
2. Message digest: DSA uses message digest algorithm (such as MD5 or SHA- 1) to digest the message to be signed to get a message digest with a fixed length. The message digest will be used as part of the digital signature.
3. Digital signature: DSA encrypts the message digest with the private key to obtain the digital signature. This digital signature will be used as the basis for verifying the authenticity of the message.