Chapter 6: Examining Hash Algorithms
If you look up the word "hash," you will see several definitions. One of the definitions is to chop food into small pieces. That is what a hash algorithm does to data. A hash algorithm will chop or reduce a variable-length block of text to produce a fixed-length hash value. The other key factor is that a hash value is a one-way function in that it cannot be restored to the original message. In this chapter, we'll describe the concept of the hash algorithm and investigate the many ways we can use a hash value.
Not all hash algorithms are the same in that some have more desirable attributes. We'll talk about what comprises an exceptional attribute when using a hash algorithm and list several desired qualities. We'll then take a look at the hash algorithms that are in use today, and why some are no longer in use. Finally, we'll take a closer look at how message authentication works, along with outlining a few practical...
