Cryptography Reference
In-Depth Information
Chapter 12
Message Authentication Codes (MACs)
A
Message Authentication Code
(MAC), also known as a
cryptographic checksum
or a
keyed hash function
, is widely used in practice. In terms of security function-
ality, MACs share some properties with digital signatures, since they also provide
message integrity and message authentication. However, unlike digital signatures,
MACs are symmetric-key schemes and they do not provide nonrepudiation. One
advantage of MACs is that they are much faster than digital signatures since they
are based on either block ciphers or hash functions.
In this chapter you will learn:
The principle behind MACs
The security properties that can be achieved with MACs
How MACs can be realized with hash functions and with block ciphers
