Gnu Privacy Guard (GnuPG) is a cryptographic utility used to generate cryptographic keys and perform other cryptographic functions. A vulnerability in the way GnuPG generates ElGamal keys has been discovered. This vulnerability renders ElGamal signing key untrustworthy.
A vulnerability in the algorithm to generate ElGamal sign+encrypt keys can permit an attacker to generate valid signatures without access to the private key. This vulnerability does not affect encrypt-only (type 16) ElGamal keys, only the ElGamal sign+encrypt key (type 20) when used to make a signature with a GnuPG version 1.0.2 or later.
A remote attacker can generate a valid signature without access to the private key.
Thanks to Werner Koch for his advisory on this issue, and Phong Nguyen for reporting this vulnerability.
|Date First Published:||2003-12-29|
|Date Last Updated:||2003-12-29 15:52 UTC|