Decrypt from SHA256

Question

I have that code to encrypt string to sha256 and next to base64:

 public static string Sha256encrypt(string phrase)
    {
        UTF8Encoding encoder = new          


        

Answer 1

It is impossible per se. SHA is a hash function, which implies it is one-way and used just for validation and similar things. Since the result of SHA-256 is of fixed length (256 bits) that also means that most of the information is lost when computing it.

You can brute-force it though, meaning that you could try and compute hash of a large number of different inputs and see if the hash matches.

Sometime in the future a cryptographic weakness may be found for SHA thus making it breakable but practically it is not a reversible function.

See details about hash functions on Wikipedia.