restructured library manual accordiung to functional group

Doc/lib/libcrypto.tex

@@ -1,9 +1,22 @@
-\chapter{CRYPTOGRAPHIC EXTENSIONS}
+\chapter{Cryptographic Services}
+\index{cryptography}
 
 The modules described in this chapter implement various algorithms of
 a cryptographic nature.  They are available at the discretion of the
-installation. 
-\index{cryptography}
+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 Python Cryptography Kit of
 further interest; the package adds built-in modules for DES and IDEA