(2026-06) A new attack to RSA with small private exponent and partial information
2026-06-20
We give a new algorithm to attack RSA with small private exponent, when some partial information of is given. The algorithm is a very simple modification of original Wiener’s attack with continued fractions, and allows us to factor whenever if we know a -fraction of the most significant bits of . The algorithm is unconditional, which is not the case in previous improvements that use Coppersmith method. As a simple example, our algorithm can be applied to break any cryptosystem with modulus of bits and , given an improvement in the original. attack of Wiener.