signing & encrypting

Aurelio Turco
Fri May 17 12:53:02 2002

David Shaw wrote:
> However, GnuPG also supports the MDC
> (modification detection code) feature of OpenPGP which includes a
> mini-signature inside the encrypted data which can also prevent this
> without signing.

I was not successful in locating any documentation on MDC.
Can someone point me to the right place, please?