Why is it not possible to reverse a hash?

One big reason you can’t reverse the hash function is because data is lost. Consider a simple example function: ‘OR’. If you apply that to your input data of 1 and 0, it yields 1. But now, if you know the answer is ‘1’, how do you back out the original data?

Why there is no way to reverse the hashing process to reveal the original password?

Hashing, however, is a one-way function that scrambles plain text to produce a unique message digest. With a properly designed algorithm, there is no way to reverse the hashing process to reveal the original password. An attacker who steals a file of hashed passwords must then guess the password.

Why is it impossible to reverse SHA256?

SHA256 is a hashing function, not an encryption function. Secondly, since SHA256 is not an encryption function, it cannot be decrypted. What you mean is probably reversing it. In that case, SHA256 cannot be reversed because it’s a one-way function.

Is there a reversible hash?

A hash function, by definition, cannot ever be reversed. If you can, it’s not a hash. It is encoding or encryption.

Is hash function can be decrypted and reversible?

The principle of hashing is not to be reversible, there is no decryption algorithm, that’s why it is used for storing passwords: it is stored encrypted and not unhashable.

Why is it important to use protocols that hash or encrypt passwords with cryptographically strong hash functions?

The core purpose of hashing is to create a fingerprint of data to assess data integrity. A hashing function takes arbitrary inputs and transforms them into outputs of a fixed length. To qualify as a cryptographic hash function, a hash function must be pre-image resistant and collision resistant.

Can we reverse sha256?

To answer your question, no, it’s not possible to “unhash” 2 and obtain 1. In order to “crack” the second hash, you would have to brute force it by computing the sha256 of other strings and comparing the result with 2.