MACs and Signatures
Apress eBooks · 2007
In this chapter, we discuss message authentication codes (MACs) and digital signature schemes. Recall from Section 1.5 that a MAC is a sequence of bits that can be attached to a message to verify where it originated and that it has not been tampered with. We will describe two types of MACs: one based on block ciphers and one based on hash functions. The MACs we describe require the sender and receiver to share a key. In many cases, it might be useful to allow anyone (without possession of a shared key) to be able to verify the originator of message, and we will thus describe how digital signatures allow you to do so.