\chapter{Cryptographic Services}
\label{crypto}
\index{cryptography}

The modules described in this chapter implement various algorithms of
a cryptographic nature.  They are available at the discretion of the
installation.  Here's an overview:

\begin{description}

\item[md5]
--- RSA's MD5 message digest algorithm.

\item[mpz]
--- Interface to the GNU MP library for arbitrary precision arithmetic.

\item[rotor]
--- Enigma-like encryption and decryption.

\end{description}

Hardcore cypherpunks will probably find the cryptographic modules
written by Andrew Kuchling of further interest; the package adds
built-in modules for DES and IDEA encryption, provides a Python module
for reading and decrypting PGP files, and then some.  These modules
are not distributed with Python but available separately.  See the URL
\url{http://starship.skyport.net/crew/amk/maintained/crypto.html} or
send email to \email{akuchlin@acm.org} for more information.
\index{PGP}
\index{Pretty Good Privacy}
\indexii{DES}{cipher}
\indexii{IDEA}{cipher}
\index{cryptography}