Partial Key Exposure Attack on RSA
Zheng Yong · Journal of Information Engineering University · 2003
Let N=pq be an nbit RSA modulus, e and d be encryption and decryption exponents and ν denote the exact number of the least significant bits that p and q equal,i.e., p≡qmod 2ν and pqmod 2ν+1.In 1998, Boneh, Durfee and Frankel proposed the partial key exposure attack on RSA: for low encryption exponent RSA, given a quarter of the bits of the decryption exponent d,an adversary can recover the entire d when ν=1. However, R.Steinfeld and Y.Zheng showed in 2001 that the partial key known attack can be prevented by choosing the modulus with large ν. In this paper,the authors conclude that for low encryption exponent RSA, known as the as n/4 least significant bits of d,one can factor N in time polynomial in n and 2ν when ν is small.