======================
     INTRODUCTION
======================

MD5sums is win32 command line software to generate MD5 hashes of files
(with progress indicator)

Author: Jem Berkes, SysDesign [ http://www.sysdesign.ca/ ]


===============
     USAGE
===============

MD5sums 1.2 freeware for Win9x/ME/NT/2000/XP+
Copyright (C) 2001-2005 Jem Berkes - http://www.pc-tools.net/

Usage: md5sums [OPTION] filespec1 [filespec2 ...]

OPTION switches:
-B  Base64 encoded output, instead of default hex format
-b  Bare output, no path headers
-e  Exit immediately; don't pause before returning
-n  No percent done indicator
-p  Pause before returning (incompatible with -e)
-s  Display statistics at end (hashing speed)
-u  Mimic output of UNIX md5 command (implies -b, -n)

Examples:
md5sums c:\temp
md5sums original.doc copy*.doc backup*.doc
md5sums -n -e d:\incoming > log


==================
     WARRANTY
==================

THIS FREE SOFTWARE COMES WITH ABSOLUTELY NO WARRANTY.
USE AT YOUR OWN RISK!


=========================
     VERSION HISTORY
=========================

Changes in version 1.2 [2005-01-31]
- UNIX compatible output fixed to match standard md5sum
- Added -B switch to get base64 encoded output (rather than default hex)
- Fixed percent indicator for files > 4 GB

Changes in version 1.1 [2002-08-03]
- Added many new command line switches
- Percent done indicator is now only updated once per second
- Executable is now UPX compressed [ http://upx.sourceforge.net/ ]


==================
     FEATURES
==================

MD5sums has user-friendly output, including a percent done indicator
when processing large files. With its various command line switches
you can customize MD5sums for use in scripts.

The UNIX compatibility switch (-u) makes the output look like that
from the Linux/BSD/UNIX md5 or md5sum commands.

Besides the normal command line usage (see examples above), MD5sums
can also be easily added to the windows shell. Use Windows Explorer
to access your user profile directory (one level up from the "Start
Menu" directory). Locate the "SendTo" folder and create a shortcut
inside it to "md5sums -p" (pause before returning).

If you have trouble locating your user profile directory, try this
at the command prompt: echo %userprofile%

After adding MD5sums to the SendTo folder, you can select one or
more files on the desktop (or in any other folder), and right-click
to "Send To" md5sums. Each selected file will be processed.


===============================
     ABOUT THE MD5 PROCESS
===============================

[Paraphrased and, in parts, quoted from RFC 1321]

The MD5 Message Digest Algorithm takes an input (in this case, a
file) and produces a 128-bit (or 16 byte) output, which can be
represented as a string of 32 hexadecimal values. This output is
a 'fingerprint' or 'message digest' for the file.

You will often find an MD5 value supplied along with files you
download off of the internet. By comparing the supplied MD5 value
to the actual value computed by the MD5sums utility, you can make
sure that the file has not been tampered with or modified.

"It is conjectured that it is computationally infeasible to
produce two messages having the same message digest, or to
produce any message having a given prespecified target message
digest."

In the context of this MD5sums utility, what this means is: if
you have a file and know what the MD5 value should be, and this
value matches the actual MD5 value obtained by using the MD5sums
utility, then the file is very likely the original file.

This is a good way to both verify that the file has not been
damaged during electronic transfers, and also to verify that the
file you are getting has not been tampered with.

For example, the MD5 value of md5sums.exe is:
da1e100dc9e7bebb810985e37875de38

Note that recent research has shown that MD5 computations are not
as immune to collisions as thought earlier. While MD5 hashes are
still excellent for file comparisons, for cryptographic strength
it is recommended that one uses a stronger hash such as SHA-1.

- Jem Berkes