Paper 2008/288

How to Launch A Birthday Attack Against DES

Zhengjun Cao

Abstract

We present a birthday attack against DES. It is entirely based on the relationship $L_{i+1}=R_{i}$ and the simple key schedule in DES. It requires about $2^{16}$ ciphertexts of the same $R_{16}$, encrypted by the same key $K$. We conjecture it has a computational complexity of $2^{48}$. Since the requirement for the birthday attack is more accessible than that for Differential cryptanalysis, Linear cryptanalysis or Davies' attack, it is of more practical significance.