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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:19:13 ADT
Alex Alten (Andrade@netcom.com)
Mon, 29 Jun 1998 22:49:04 -0700
At 03:13 PM 6/29/98 -0400, Perry E. Metzger wrote:
>
>Cicero writes:
>> Alex Alten <Andrade@netcom.com> wrote:
>> >At 04:20 PM 6/24/98 -0400, mgraffam@mhv.net wrote:
>> >>Uh.. why not just use a hash algoritm to hash a passphrase down to
>> >>128 bits, if you really only want 64, just truncate it.
>> >
>> >Never truncate a hash, unless you understand its design.
>> >
>> >- Alex
>>
>> Can you give an example to illustrate your point? Are you saying that
>> there are instances where truncating SHA-1 or MD5 can lead to a
>> problem?
>
>I'm actually under the impression that using a truncated hash output
>in lieu of the hash produces a more secure result under many
>circumstances.
>
No. Hashes do not have perfect random output. If you truncate the output
you will introduce vulnerabilities not anticipated by the designer.
- Alex
-- Alex Alten Andrade@Netcom.Com P.O. Box 11406 Pleasanton, CA 94588 USA (510) 417-0159
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:19:13 ADT