[SpamCop-List] Re: Att: Paul Johnson: PGP signature in spam

[Graeme Leith]

helge wrote:

> I have a problem with the word hash, though. Ordinary dictionary 
> explanations don't cover the sense you are using, but it seems to be 
> programmer's jargon as found at
> http://dictionary.reference.com/search?q=hash%20coding ,
> not very illuminating for a layperson, but I get the idea.

A hash, in the cryptographic usage, is an algorithm that takes variable 
length input data and converts it to a short, fixed length string, 
unique to the input data. It's kind of like a fingerprint for a digital 
document. If you get fingerprinted several times, you always generate 
the same fingerprint. If you fingerprint somebody else, it is highly 
unlikely they will generate a print the same as yours.