According to Dr. Henson, and in response to issues with `openssl enc`
when using GCM mode
(http://groups.google.com/d/msg/mailing.openssl.users/hGggWxfrZbA/Tc-VHdJDqfwJ):
There is no problem with GCM it's a problem
with the "enc" utility. It doesn't support GCM
mode properly (it doesn't store/retrieve the
tag) and it should either be extended to
support GCM mode or GCM mode not
allowed in enc at all.
This patch adds text under the BUGs section and warns of authenticated
encryption modes. The entry is similar to the warning given for
ciphers (and the cipher warning immediately proceeds it).
*****
diff --git a/doc/apps/enc.pod b/doc/apps/enc.pod
index 3dee4ed..7f03a62 100644
--- a/doc/apps/enc.pod
+++ b/doc/apps/enc.pod
@@ -326,4 +326,8 @@ The B<enc> program only supports a fixed number of algorithm
certain parameters. So if, for example, you want to use RC2 with a
76 bit key or RC4 with an 84 bit key you can't use this program.
+The B<enc> program does not support authenticated encryption modes
+like CCM and GCM. The utility does not store or retrieve the the
+authentication tag.
+
diff --git a/doc/apps/enc.pod b/doc/apps/enc.pod
index 3dee4ed..7f03a62 100644
--- a/doc/apps/enc.pod
+++ b/doc/apps/enc.pod
@@ -326,4 +326,8 @@ The B<enc> program only supports a fixed number of
algorithms with
certain parameters. So if, for example, you want to use RC2 with a
76 bit key or RC4 with an 84 bit key you can't use this program.
+The B<enc> program does not support authenticated encryption modes
+like CCM and GCM. The utility does not store or retrieve the the
+authentication tag.
+
=cut
