19

Attacks on Cryptography

Winston Churchill, the British statesman and Prime Minister during World War II, famously said: ”Those who fail to learn from history are doomed to repeat it.” This is as valid for cryptography as it is for warfare. In addition, understanding how attacks work – first in general and subsequently on TLS – allows us to build up an in-depth understanding of why TLS is designed the way it is.

In this chapter, we discuss well-known attack types targeting cryptography. We specifically cover attack types relevant to cryptographic protocols such as TLS. The larger part of this chapter deals with attacks on protocols themselves, that is, attacks that are independent of the underlying cryptographic primitives. This is complemented by a brief discussion of attack types targeting cryptographic mechanisms used within a protocol, in particular attacks on encryption schemes and hash functions. We omit attacks on public key cryptography to avoid redundancy...