Introduction to Cryptography with Coding Theory, 3rd Edition

11.2 Simple Hash Examples

There are many families of hash functions. The discrete log hash function that we described in the previous section is too slow to be of practical use. One reason is that it employs modular exponentiation, which makes its computational requirements about the same as RSA or ElGamal. Even though modular exponentiation is fast, it is not fast enough for the massive inputs that are used in some situations. The hash functions described in this section and the next are easily seen to involve only very basic operations on bits and therefore can be carried out much faster than procedures such as modular exponentiation.

We now describe the basic idea behind many cryptographic hash functions by giving a simple hash function that ...