12 Nov
2007
12 Nov
'07
5:34 p.m.
On 12 Nov 2007 at 7:03, dwight elvey wrote:
What are SHA hashes? I've not heard that term
before.
The CRC chips I was looking at were from AMD when I
worked for Systems Industries. Now I work for AMD
but the only thing they work on today are processors.
SHA = "Secure Hash Algorithm"--really a family of algorithms. The
most commonly encountered are the SHA-1 group. Here's the FIPS pub
detailing the whole family:
http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
These are most useful when one wants to reduce the possibility of
data being altered. The algorithms have a cryptographic basis,
rather than a simple polynomial as in a CRC and so it's *very*
difficult to modify data in such a manner as to yield the same hash
as the unmodified data.
Cheers,
Chuck