Attack against Ibrahim's Distributed Key Generation for RSA

Distributed RSA key generation protocols aim to generate RSA keys in such a way that no single participant of the protocol can learn factorization of the RSA modulus. In this note we show that two recent protocols of this kind (Journal of Network Security, Vol. 7, No. 1, 2008, pp. 106-113 and Vol. 8, No. 2, 2009, pp. 139-150) fail their security target. We present an attack that can be launched by any protocol participant after terminating distributed key generation process.

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