Simple encryption proposal. Comments ?

[Paul Rubin]

> ># _test2()    # depends on secrand.py module, not included
>                                                ^^^^^^^^^^^^
> We seem to a chain going ;-) Google doesn't ... Um, where might one ...

Secrand is used only by one of the testing functions, so it's not
needed to use that base52 module.  It's *nix-specific since it reads
bytes from /dev/urandom.  But here it is:

# ===== secrand.py ========================================================

# Secure random number generator

# Copyright 2001 Paul Rubin, Fort GNOX Cryptography
# Copying permissions: GNU General Public License version 2.

# $Id: secrand.py,v 1.1 2002/12/20 19:42:02 phr Exp phr $

class _secrand:
    def __init__(self):
        self.__f = open("/dev/urandom")
    def getbytes(self,nbytes):
        return self.__f.read(nbytes)
    def gethex(self,nbytes):
        import binascii
        return binascii.hexlify(self.getbytes(nbytes))
    def getlong(self,nbytes):
        return long(self.gethex(nbytes), 16)
    def getstring(self,nbytes):
        import base64
        x = base64.encodestring(self.getbytes(nbytes))
        # chop newline and trailing '=' signs
        x = x[:-(-nbytes%3)-1]
        return x

secrand = _secrand()