What is Hashing or Hashing Function?

[longwar]

hi all,
lately, i heard ppl talking about this 'hashing function', 'hashing check' what in the world does that totally means? i got really no idea in that. pls someone, give me a clear explanation on this. thks

longwar

[Merri]

Wikipedia explains Hash function pretty well.

[Hack]

Moved to General Developer

[szlamany]

We use hash logic in bank transmissions...

Let's say we want to put the figure 123456 into a file for transmitting. They want to make sure the file arrives without any transmission errors and that the 123456 came across cleanly.

You can add the digits 1+2+3+4+5+6 = 21 and then put the "last" digit of the "hash" 21 onto the string - making 1234561 be the transmitted value.

Now when reviewing the figure - you take the first 6 digits and make sure the "hash" returns a value ending in "1".

There are many different ways of doing this - just a simple example...