RSA Digital Key Signature + RSA-PSS

To sign, you

encrypt the message with the private key (instead of the public key), which produces a signature (a random element in the group).

To verify a signature,

you decrypt the signature with the public key (instead of the private key). The signature is valid if it gives you back the original message

Sign a message by

computing signature = message^d mod N

Verify a signature by computing

signature^e mod N and check that it is equal to the

message

RSA-PSS Step 1

Encode the message using the PSS encoding algorithm

RSA-PSS Step 2

Sign the encoded message using RSA (as was done in the PKCS#1 v1.5 standard)