CODEWITHSUNDEEP
c#cryptography
ThunderCougarFalconBird
ThunderCougarFalconBird

Reputation: 13

Why does this method for computing a SHA-256 hash always return a string of 44 characters?

First off, please ignore that there is no salt. I removed the salt in order to simplify things as much as possible.

The following always outputs a 44 character string:

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;

namespace ConsoleApplication1
{
    class Program
    {
        private static HashAlgorithm hashAlgorithm = new SHA256CryptoServiceProvider();

        static void Main(string[] args)
        {
            string blah = ComputeHash("PasswordLongBlah646468468Robble");
            Console.WriteLine(blah.Length);
            Console.WriteLine(blah);
        }

        private static string ComputeHash(string input)
        {
            Byte[] inputBytes = Encoding.UTF8.GetBytes(input);

            Byte[] hashedBytes = hashAlgorithm.ComputeHash(inputBytes);

            return Convert.ToBase64String(hashedBytes);
        }
    }
}

Output of this application:

44
K5NtMqCN7IuYjzccr1bAdajtfiyKD2xL15Eyg5oFCOc=

If I am not mistaken, the output should be:

64
2b936d32a08dec8b988f371caf56c075a8ed7e2c8a0f6c4b979132839a0508e7

What is going on here?

Upvotes: 1

Views: 2864

Answers (2)

CodeCaster
CodeCaster

Reputation: 151604

You're converting it to a Base64 string...

You might want to use this instead:

 // Cut bad code

Edit: which once again is a poor man's implementation of the BitConverter.ToString() posted above. Why is the internet filled with reimplementations of existing framework functionality when searching for common functionality like "string to hex"? ;-(

Upvotes: 0

Tom Zych
Tom Zych

Reputation: 13576

See where it says Convert.ToBase64String(hashedBytes)? It's not giving you a hexadecimal string (4 bits per character) - it's in base 64 (6 bits per character).

Upvotes: 3

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