C# Hash String using SHA256 Algorithm

In today’s digital world, data security is of utmost importance. One common technique used to protect sensitive information is hashing. Hashing allows you to transform data into a fixed-size string of characters, making it nearly impossible to reverse-engineer the original data. In this article, we will explore how to hash a string using the SHA256 algorithm in C#.

What is SHA256?

SHA256 (Secure Hash Algorithm 256-bit) is a widely used cryptographic hash function that belongs to the SHA-2 (Secure Hash Algorithm 2) family. It takes an input (in our case, a string) and produces a 256-bit hash value. The resulting hash is unique to the input data, meaning that even a small change in the input will result in a significantly different hash.

Using the SHA256 Algorithm in C#

To hash a string using the SHA256 algorithm in C#, we can utilize the SHA256Managed class from the System.Security.Cryptography namespace.

// Import the required namespace
using System.Security.Cryptography;

// Function to hash a string using SHA256
public static string HashString(string input)
using (SHA256Managed sha256 = new SHA256Managed())
// Convert the input string to a byte array
byte[] inputBytes = Encoding.UTF8.GetBytes(input);

Copy code
    // Compute the hash value
    byte[] hashBytes = sha256.ComputeHash(inputBytes);

    // Convert the byte array to a hexadecimal string
    StringBuilder stringBuilder = new StringBuilder();
    for (int i = 0; i < hashBytes.Length; i++)

    return stringBuilder.ToString();


Let’s break down the code:

  • We import the System.Security.Cryptography namespace, which contains the necessary classes for cryptographic operations.
  • We define a static method named HashString that takes a string input and returns the hashed string.
  • Within the method, we create an instance of the SHA256Managed class.
  • We convert the input string to a byte array using the UTF-8 encoding.
  • We compute the hash value by calling the ComputeHash method of the SHA256Managed instance.
  • The resulting hash value is a byte array.
  • We convert the byte array to a hexadecimal string representation using a StringBuilder.
  • Finally, we return the hashed string.

Example Usage

Now, let’s see how we can use the HashString method:

string input = "Hello, World!";
string hashedString = HashString(input);
Console.WriteLine("Input: " + input);
Console.WriteLine("Hashed String: " + hashedString);

This code will output:

Input: Hello, World!
Hashed String: f7ff9e8b7bb2e09b70935a5d785e0cc5d9d0abf0d2f40bdc10b4765e2f8db687

As you can see, the input string “Hello, World!” is transformed into a unique hash value using the SHA256 algorithm.


Hashing strings using the SHA256 algorithm provides a secure way to protect sensitive information. By leveraging the SHA256Managed class from the System.Security.Cryptography namespace in C#, you can easily generate a unique hash value for any given input string. Whether you’re working on password storage, data integrity checks, or any other scenario that requires data security, the SHA256 algorithm is a reliable choice.

Implementing SHA256 hashing in your C# applications will help you safeguard your data and enhance the overall security of your software.





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