Can’t the steps be reversed one by one to get back the original?
In: Mathematics
The thing about how these hash algorithms work is they reduce and mix the data in such a way that you just don’t have enough data to reverse them to find the original.
Lets demonstrate with an extremely simple hash algorithm. We can make A=1, B=2, C=3 and so on. I’ll choose a word, add the numbers made from the letters together, and then take just the last 2 digits.
The hash of the word is 82.
What is the word? It could be anything! In fact there are lots of possible words that would make the same hash. It’s impossible to even say how long the word is.
SHA256 is 256 bits long, but it can hash files that are megabytes or gigabytes in size. So there must be lots of theoretically possible files that would have the same hash, it’s just very unlikely to hit them because there are so many combinations in the hash. But if you were trying to work backwards you’d have no idea which of the possible files it was.
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