A weakness has been identified in the handling of ElGamal keys in GnuPG, which exposes the private key.

The problem is a that certain versions of GnuPG creates ElGamal sign+encrypt keys (type 20) in a cryptographically weak way. This can be exploited to derive the private key.

In an advisory from the developers of GnuPG, it is stated that all ElGamal type 20 keys should be considered compromised.

This affects ElGamal type 20 keys generated with GnuPG 1.0.2 to 1.2.3.

ElGamal encrypt-only keys (type 16) are not affected.

Further details are available in the original advisory.

Solution
Future versions of GnuPG will not include support for ElGamal type 20 keys.
Further details available in Customer Area

Provided and/or discovered by
Phong Nguyen

Changelog
Further details available in Customer Area

Original Advisory
http://lists.gnupg.org/pipermail/gnupg-users/2003-November/020772.html

Other references
Further details available in Customer Area

Deep Links
Links available in Customer Area