Cryptanalysis of a robust protocol for generating shared RSA parameters

At IMA-Crypto & Coding´ 99, A. M. Barmawi et al. proposed a robust protocol for generating shared RSA parameters, which was claimed to be secure and robust from cheaters and malicious parties. In this paper, we propose a cryptanalysis of A. M. Barmawi´s protocol and show that every valid participating party can recover the factorization of the RSA modulus N with the computational complexity O(log³N). Therefore, the secret RSA key parameters p, q, d axe exposed to all the participating parties and A. M. Barmawi´ s protocol is totally broken.