PC Hobbyist

I've heard the term "hash" for years, but I never really bothered to try and understand until now. I've been reading some things online about it, but I'm curious if I have the right general idea.

Correctly if I'm wrong:

A hash is an algorithm that looks at a file's unique data information and produces a combination of numbers and letters that uniquely identifies that file. It can be used to confirm that the copy of the file you have is the original, unaltered version that the author created.


And here are a couple of questions:

1. So, if the file is altered in any way, it will have a new hash value? For example, every time I edit a picture or a Word document, the hash value changes?

2. Does every single file in my computer have a hash value?

3. How can I check what the hash value of a file is? What program can I use?

4. Are "hash", "checksum", and "hash checksum" the same thing?

5. Do programs that scan your computer for duplicate files, do so by looking at the hash value?


Thanks for helping me understand this a bit better (he-he no pun intended ).

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