hash algorithm

Timo Schulz twoaday@freakmail.de
Mon Jul 7 22:30:01 2003

On Mon Jul 07 2003; 16:19, CL Gilbert wrote:

> What is the hash algorithm for, or what is the hash itself for?  And why

The hash algorithm is used to calculate the message digest over the
data. It's like a digital fingerprint which is unique. It is used
during the signing and verification process.

> do I have several choices?  Is one better or preferred for a particular
> situation or reason?

You have several choices because some algorithms MUST use a special
hash algorithm. For example the DSS prescribes SHA-1 as the message
digest algorithm.

But if you use RSA you are free to chose RMD-160 or SHA-1 or even MD5.
It's up to you to select one. RMD-160 and SHA-1 do not have any known
weaknesses so it's a personal preference.


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