HASH routine against a files contents?

[ronb...@hotmail.com]

We are a small COBOL/TACL shop and have a requirement to provide a MD5
HASH on an unstructured file both BEFORE and AFTER we process a
file.

We found a few MD5.C routines through searching, but they all only
provide the hash against a STRING, which doesn't staisfy the
requirement. We are not well versed enough in C to make the necessary
adjustments to the code, so are wondering if there is an existing set
of code that will work on Tandem that provides the hash against a
FILE instead of simply a STRING that someone has found and we have
missed?

Thanks in advance for any assistance you could provide.

-ron
rb......@walottery.com

[TEP]

There's a utility called SWID which generates a unique fingerprint for
the contents of a file. It was designed for managing the integrity of
NonStop system software files, but you can use it on your own files as
well. I'm not sure if the hash is exactly identical to an MD5 hash, but
it might be worth checking, depending how flexible your requirements are.
Documentation at http://docs.hp.com/en/527243-004/527243-004.pdf

T.

[ronb...@hotmail.com]

On May 5, 2:01 pm, TEP <cncncc...@gmax.com> wrote:

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Thanks for the quick response - we're checking now to see if this
would meet their requirements.

[Keith Dick]

Here is a pointer to a web page from which you can get the C code for a public domain program that computes the MD5 hash of a file. There is code for Windows and Unix. I imagine you would be able to get the Unix code working on a NonStop system without much trouble, though I have not looked at the program to see how much work it might be to do that.

http://www.fourmilab.ch/md5/

If you want help getting it to work on a NonStop system, I probably could assist you, though I don't have ready access to a NonStop system do to much work myself. I might be able to get a friend to let me try some compiles on a NonStop system, but I'd rather not push it.

[ronb...@hotmail.com]

On May 6, 7:34 am, Keith Dick <kdic...@comcast.net> wrote:

> If you want help getting it to work on a NonStop system, I probably could assist you, though I don't have ready access to a NonStop system do to much work myself.  I might be able to get a friend to let me try some compiles on a NonStop system, but I'd rather not push it.- Hide quoted text -

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You ROCK Dude!!!!! Much thanks for all your help

[ronb...@hotmail.com]

On May 5, 2:01 pm, TEP <cncncc...@gmax.com> wrote:

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SWID was determined to not be a qualified substitute for the MD5 HASH
routine. The purpose of the HASH requirement is to prevent anyone
from manually manipulating the input file after accepting it and prior
to processing it - preventing potential illegal stacking of numbers or
such. The SWID actually allows some cases of file manipulation where
it doesn't affect the fingerprint, so the client turned this option
down.

Thanks for the suggestion and the information though.

[morris...@gmail.com]

> Thanks for the suggestion and the information though.- Hide quoted text -

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A alternative solution would be to change the security/ownership of
the file to prevent other programs/user from accessing the file. The
Tandem File System will enforce your security wishes very well.

[MicroTech]

Verbatim from his website, here's John Walker's description of his
implementation of "MD5 for files":

\QUOTE ON
Command-line utility which computes and checks message digests
(digital signatures) generated by the MD5 algorithm as defined by RFC
1321. This program is handy for software installation, file
verification, and other system administration shell scripts and Perl
programs. Includes complete C source code for Unix and a ready to run
Win32 executable. New version 2.0 adds multiple file signature
generation (including wildcard expansion in the Win32 version),
tagging signatures with file names, and optional lower case letters in
hexadecimal output.
\QUOTE OFF

If this seems to fit your needs, you can download the application from
John's website, at:

http://www.fourmilab.ch/md5/

The download includes a Win32 executable (plus the full C source), so
if you wish to avoid the hassles of uploading the Enscribe file to a
PC running Windows before hashing out its MD5 signature, you will have
to compile the source, mutatis mutandum, on the Tandem.

John Walker's site is a veritable treasure-chest, so if you go there
for MD5, pay a visit to his home page as well!

Cheers,

Henry Norman
MicroTech Consulting
http://groups.google.com/group/MicroTech_Software

[rip_uno]

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No - we aren't afraid we are going to change the file - the client
needs visual assurances with each day's processing that the file isn't
changed while it is out o ftheir hands. This dispels fears that the
lottery is getting rigged in some fashion or the other. ;-)

[rip_uno]

Thanks for the tip Henry, and the link. With Keith Dick's
*invaluable* assistance, we now have a working Tandem C program and
are VERY satisfied with the results. I will keep this link for future
use though.

[MicroTech]

> Thanks for the tip Henry, and the link.  With Keith Dick's
> *invaluable* assistance, we now have a working Tandem C program

Glad we could help! Yes, Keith is a supportminded analyst of original
Tandem vintage!

Henry Norman
MicroTech Consulting