MD5, SHA1 (can hash size be adjusted)

[Jesper]

Hi,

Is it possible to adjust the hash size of the algorithm used. I would like
to get a hash size less than 160 bit.

Regards

[Jon Skeet [C# MVP]]

Jesper <Je****@discussions.microsoft.com> wrote:

Is it possible to adjust the hash size of the algorithm used. I would like
to get a hash size less than 160 bit.

I believe the MD5 algorithm is specifically defined to be 128-bit, and
and SHA-1 is defined to produce a 160-bit hash, rather than being
defined for an arbitrary hash size.

In other words, no. Of course, you could always ignore half the hash...
a well-behaved cryptographically-strong hash should be equally pseudo-
random in all bits, so by taking only part of it you should just get a
weaker version in terms of the probability of hash collisions.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[PhilipPainter]

You can use MGF1 which uses SHA1 underneath. MGF1 can produce a hash of any
size.
sEE IEEE Std 1363-2000 [26] and the draft ANSI X9.44 [1].

--
Philip Painter, HP
"Jesper" wrote:

Hi,

Is it possible to adjust the hash size of the algorithm used. I would like
to get a hash size less than 160 bit.

Regards

[PhilipPainter]

You can use MGF1 which uses SHA1 underneath. MGF1 can produce a hash of any
size.
sEE IEEE Std 1363-2000 [26] and the draft ANSI X9.44 [1].

--
Philip Painter, HP
"Jesper" wrote:

Hi,

Is it possible to adjust the hash size of the algorithm used. I would like
to get a hash size less than 160 bit.

Regards