Lecture 10: Attacking RSA

William Stein

Date: Math 124 $\quad$ HARVARD UNIVERSITY $\quad$ Fall 2001

Nikita's public key is $(n,e)$. If we compute the factorization of $n=pq$, then we can compute $\varphi (n)$ and hence deduce her secret decoding number $d$. Thus attempting to factor $n$ is a way to try to break an RSA public-key cryptosystem. In this lecture we consider several approaches to ``cracking'' RSA, and relate them to the difficulty of factoring $n$.