Cryptographic Services
**********************

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:

* "hashlib" --- Secure hashes and message digests

  * Key derivation

* "hmac" --- Keyed-Hashing for Message Authentication

* "md5" --- MD5 message digest algorithm

* "sha" --- SHA-1 message digest algorithm
