Question

Is it possible to retrieve the original message from a SHA-1 encrypted message? If I have an SHA -1 encrypted message, what all paratmeters do i need to get the original message from it?

Answer 1

I answered a similar question already: Python SHA1 DECODE function

In short, no it is not possible. The whole point of hashing is to take some long string and turn it into a small one. Hashing is destructive and you lose data, so it is irreversible.

Also, to make things more fun, infinitely many strings have the same hash¹. It is impossible to generate a unique string with a given hash unless you know more information about the input.

^{1: There are tons of hash functions and some may have “special” hashes that are only generated when you give a specific input to the function. Aside from those rare cases (if they even exist), every other output hash has infinitely many input strings.}