Public-key Cryptography: Theory and Practice

5.4. Digital Signatures

Suppose an entity (Alice) is required to be bound to some electronic data (like messages or documents or keys). This binding is achieved by Alice digitally signing the data in such a way that no party other than Alice would be able to generate the signature. The signature should also be such that any entity can easily verify that it was Alice who generated the signature. Digital signatures can be realized using public-key techniques. The entity (Alice) generating a digital signature is called the signer, whereas anybody who wants to verify a signature is called a verifier.

We have seen in Section 5.2 how the encryption and decryption transforms f_e, f_d achieve confidentiality of sensitive data. If the set of all possible ...