This is an MD5 library for Lua 5.1. It is based on the MD5 library by Rivest,
described in rfc1321, but also it supports several other libraries that have
a similar API (including libraries that compute SHA1 instead of MD5). For
more information in MD5 and SHA1, see
	http://en.wikipedia.org/wiki/MD5
	http://en.wikipedia.org/wiki/SHA_hash_functions

To try the library, just edit Makefile to reflect your installation of Lua and
your MD5 or SHA1 library (see below) and then run make. This will build the
library and run a simple test. For detailed installation instructions, see
	http://www.tecgraf.puc-rio.br/~lhf/ftp/lua/install.html

There is no manual but the library is simple and intuitive; see the summary
below. Read also test.lua, which shows the library in action.

This code is hereby placed in the public domain.
Please send comments, suggestions, and bug reports to lhf@tecgraf.puc-rio.br .

-------------------------------------------------------------------------------

md5 library:
 clone(c)                reset(c)                version 
 digest(c or s,[raw])    tostring(c) 
 new()                   update(c,s) 

-------------------------------------------------------------------------------

* Finding and selecting an MD5 library

If you're running Linux, you probably already have Rivest's library installed
somewhere. The problem is finding where. Most probably it's in libcrypto,
which is part of openssl (or libsasl, but don't use /usr/include/sasl/md5.h).
The Makefile assumes this as default.

If you can't find an MD5 library in your system, then download one from
	http://userpages.umbc.edu/~mabzug1/cs/md5/md5.html

lmd5.c supports all three C libraries mentioned in that web page: Rivest's
original library from rfc1321, Deutsch's library, and Plumb's public domain
implementation, which can be downloaded at
	http://archiv.tu-chemnitz.de/pub/1999/0004/data/md5/

Those libraries are quite small and easy to compile. They are not included in
this package because they are easily available and have their own licenses.

* Finding and selecting a SHA1 library

lmd5.c also supports SHA1. If you're running Linux, you probably already have
a SHA1 library installed somewhere. If you have libcrypto, then select it in
the Makefile. Otherwise, extract the C code from rfc3174:
	http://www.faqs.org/rfcs/rfc3174.html

A public domain SHA1 library is available in skalibs:
	http://www.skarnet.org/software/skalibs/libstdcrypto.html
	http://www.skarnet.org/software/skalibs/install.html
but you'll have to spend a little time making its SHA1 module into a
standalone module, without dependencies. It's not hard at all. If you have
problems, let me know.