A New Factoring Attack on Multi-Prime RSA with Small Prime Difference.
Mengce Zheng, Honggang Hu · 2015
In this paper, we study the security of multi-prime RSA whose modulus is N = p1p2 pr for r 3 with small prime difference of size N . In ACISP 2013, Zhang and Takagi showed a Fermat-like factoring attack, which can directly factor N for < 1 r2. We improve this bound to theoretically achieve < 2 r(r+2) by a new factoring attack. Furthermore, we also analyse specific MPRSA with imbalanced prime factors. Experimental results are provided to show the efficiency of our attack.