Real-World Cryptography

7 Signatures and zero-knowledge proofs

This chapter covers

• Zero-knowledge proofs and cryptographic signatures
• The existing standards for cryptographic signatures
• The subtle behaviors of signatures and avoiding their pitfalls

You’re about to learn one of the most ubiquitous and powerful cryptographic primitives—digital signatures. To put it simply, digital signatures are similar to the real-life signatures that you’re used to, the ones that you scribe on checks and contracts. Except, of course, that digital signatures are cryptographic and so they provide much more assurance than their pen-and-paper equivalents.

In the world of protocols, digital signatures unlock so many different possibilities that you’ll run into them again and again in ...