Digital signatures and PK encryption
PK encryption: People send you messages encrypted with the aid of your public key; you decrypt these with your corresponding secret key
Digital signatures: You sign using your secret key; people check the signature using your corresponding public key
The digital signature algorithm is a lot like the Diffie-Hellman algorithm
The best-known public-key algorithm, called RSA, can be used both for encryption and digitial signatures. In fact, you can even use the same secret key for decrypting and signing.
Is it a good idea to use the same secret key for decrypting and signing?