Vista - keys for a hash

If I have a hash but don't know the keys, is there a method that will return the keys?
Thanks,
Joe

zim wrote:
This is not a VBScript question, but the answer is no. Given a hash there
should be no way to determine anything about it.

--
Richard Mueller
MVP Directory Services
Hilltop Lab - http://www.rlmueller.net
--

On Mar 6, 4:34*am, "Richard Mueller [MVP]" <rlmueller-
nos...@xxxxxx> wrote:Richard, I followed the link I got from Bishop. On the website was a
VBS named: "Calculate_MD5_Hash.vbs"
When I tested it, I got 4544835ce29dd5465ee84151106e7cd8
using a simple test file as source. BUT when I compared the returned
value with the result from
another make-hash-file (an EXE named: "mstMD5.exe",) then I got
another value: 30da2c385a8e2600c929b59cbf62b909
Since the two values are different, only one, or both programs seems
less useful.
Should not the result be the same value when the same source file was
used on both the make-hash-programs ?

Benny,
www.fineraw.com

"Benny Pedersen" <b.pedersen@xxxxxx> wrote in message
news:844a9711-e37d-4784-a64e-3f6e31de1a4b@xxxxxx
On Mar 6, 4:34 am, "Richard Mueller [MVP]" <rlmueller-
nos...@xxxxxx> wrote:Richard, I followed the link I got from Bishop. On the website was a
VBS named: "Calculate_MD5_Hash.vbs"
When I tested it, I got 4544835ce29dd5465ee84151106e7cd8
using a simple test file as source. BUT when I compared the returned
value with the result from
another make-hash-file (an EXE named: "mstMD5.exe",) then I got
another value: 30da2c385a8e2600c929b59cbf62b909
Since the two values are different, only one, or both programs seems
less useful.
Should not the result be the same value when the same source file was
used on both the make-hash-programs ?

Benny,
www.fineraw.com

-------------
The resulting hash value will be the same if:

1. The same input is hashed.
2. The same algorithm is used.
3. The same key or salt value is used (if there is one).

Assuming you supplied the same input, then the algorithms used by the two
programs are not the same. However, I don't know of any variations in the
implentation if MD5. Perhaps one of the programs introduces a secret "salt"
value. MD5 is not a keyed hash algorithm. If a "salt" value is used, either
the salt must be appended to the hash (so it can be used to duplicate the
result) or the program always uses the same secret salt value. That's just a
guess, because if MD5 is used in both cases, a given input should always
hash to the same value.

My source (Handbook of Applied Cryptography, by Menezes, Oorschot, and
Vanstone) say that MD5 should hash the string "a" to the following 128-bit
value:

0cc175b9c0f1b6a831c399e269772661

Maybe you can use this information to tell which program is really MD5. My
best guess is that the other program adds a secret "salt" value to the
input.

--
Richard Mueller
MVP Directory Services
Hilltop Lab - http://www.rlmueller.net
--