A reaction attack on a public key cryptosystem based on the word problem
Wagner and Magyarik outlined a conceptual public key cryptosystem based on the hardness of the word problem for finitely presented groups. At the same time, they gave a specific example of such a system. We prove that in the present form their approach is vulnerable to so-called reaction attacks. In particular, for the proposed instance it is possible to retrieve the private key just by watching the performance of a legitimate recipient.
word problem finitely presented groups public key encryption cryptanalysis