How to Hash a String With SHA256 in C#

Muhammad Zeeshan Feb 02, 2024

Csharp Csharp Hash

In the following article, you will learn how to hash a string using the sha256 algorithm in the C# programming language.

In cryptography, hashing refers to a method that maps a binary string of an indeterminate length to a short binary string with a defined length. This short binary string is known as a hash.

Hash functions are another name for hashing. It is standard practice to use hash functions to protect confidential information like passwords and digital certificates against unauthorized access.

Hash a String With SHA256 in `C#`

To better explain how to hash a string using sha256, the following example can guide you.

To begin, import the following libraries:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;

First, we’ll create a function named HashWithSha256 that will convert user input to hash output. This function will take user input as a parameter.

static string HashWithSha256(string ActualData) {}

To obtain the SHA256 hash, we will utilize the SHA256 class. It is necessary to first create a SHA256 hash object by using the .Create() method.

using (SHA256 s = SHA256.Create()) {}

Then, use the Encoding.GetBytes() function to convert the provided string into a byte array.

byte[] bytes = s.ComputeHash(Encoding.UTF8.GetBytes(ActualData));

Utilize the StringBuilder to convert the byte array into a string.

StringBuilder b = new StringBuilder();
for (int i = 0; i < bytes.Length; i++) {
  b.Append(bytes[i].ToString("x2"));
}

Let’s start by constructing the string we want to convert.

string s1 = "Muhammad Zeeshan";
Console.WriteLine("User Input: {0}", s1);

Lastly, you will need to store the output of the input string to a local variable HashString after you provide it as a parameter to the HashWithSha256 function.

string HashString = HashWithSha256(s1);
Console.WriteLine("Hash Output: {0}", HashString);
Console.ReadLine();

Complete Source Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;

namespace HashStringByZeeshan {
  class Program {
    static void Main(string[] args) {
      string s1 = "Muhammad Zeeshan";
      Console.WriteLine("User Input: {0}", s1);
      string HashString = HashWithSha256(s1);
      Console.WriteLine("Hash Output: {0}", HashString);
      Console.ReadLine();
    }

    static string HashWithSha256(string ActualData) {
      using (SHA256 s = SHA256.Create()) {
        byte[] bytes = s.ComputeHash(Encoding.UTF8.GetBytes(ActualData));
        StringBuilder b = new StringBuilder();
        for (int i = 0; i < bytes.Length; i++) {
          b.Append(bytes[i].ToString("x2"));
        }
        return b.ToString();
      }
    }
  }
}

Output:

User Input: Muhammad Zeeshan
Hash Output: b77387c5681141bfb72428c7ee23b67ce1bc08f976954368fa9cab070ffb837b

Author: Muhammad Zeeshan

I have been working as a Flutter app developer for a year now. Firebase and SQLite have been crucial in the development of my android apps. I have experience with C#, Windows Form Based C#, C, Java, PHP on WampServer, and HTML/CSS on MYSQL, and I have authored articles on their theory and issue solving. I'm a senior in an undergraduate program for a bachelor's degree in Information Technology.