Real-World Cryptography

2 Hash functions

This chapter covers

• Hash functions and their security properties
• The widely adopted hash functions in use today
• Other types of hashing that exist

Attributing global unique identifiers to anything, that’s the promise of the first cryptographic construction you’ll learn about in this chapter—the hash function. Hash functions are everywhere in cryptography—everywhere! Informally, they take as input any data you’d like and produce a unique string of bytes in return. Given the same input, the hash function always reproduces the same string of bytes. This might seem like nothing, but this simple fabrication is extremely useful to build many other constructions in cryptography. In this chapter, you will learn everything there is ...