GNUPG and Cast6

[David Shaw]

On Aug 29, 2013, at 2:01 PM, Csabi <csabi.hlw at gmail.com> wrote:

> Hi all,
> 
> Why does not support GNUPG the CAST6 (256 bit key) variant of the CAST algorithm?
> It supports the CAST5 (128 bit key) variant and it is the default cipher.

There never was a really good reason to support it.  The OpenPGP working group added TWOFISH as a 256-bit cipher (and not incidentally a 128-bit blocksize), and later AES.  There is nothing specifically wrong with CAST6, but given that OpenPGP has both TWOFISH and AES, there isn't really a pressing reason to include CAST6 too.

David