Hi All, This has been bugging me for some time....
When Crypto++ and GnuPG interop using ElGamal, Crypto++ often throws a bad element exception when validating the GnuPG keys. It appears GnuPG does not choose a q such that q - 1 is prime (in the general form of p = qr + 1). That causes a failure in Crypto++'s Jakobi test. I could not find a paper stating q - 1 non-prime was OK (on Google and Google Scholar). I would think that q - 1 prime would be a requirement, since some algorithms run in time proportional to q - 1 (for example, Pollard's Rho). What are the key generation requirements for ElGamal Encryption and Signature schemes? Jeff _______________________________________________ cryptography mailing list [email protected] http://lists.randombit.net/mailman/listinfo/cryptography
