Enecrypt and Decrypte

SHA256 Class provides mechanism to encrypt any input to a fixed length hashed data based on SHA-256 algorithm. Hashing is a one way cryptographic function, it cannot be decrypted back to the original text.

If your requirement is to encrypt your password and at some point of time see Original password, you can use AES algorithm (AES Class), RSA Algorithm (RSACryptoServiceProvidervider Class). Below is a sample.

using System;
using System.Security.Cryptography;
using System.Text;

class RSACSPSample
{
    static void Main()
    {
        try
        {
            UnicodeEncoding ByteConverter = new UnicodeEncoding();
            byte[] dataToEncrypt = ByteConverter.GetBytes("Data to Encrypt");
            byte[] encryptedData;
            byte[] decryptedData;

            using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
            {
                encryptedData = RSAEncrypt(dataToEncrypt, RSA.ExportParameters(false), false);
                decryptedData = RSADecrypt(encryptedData, RSA.ExportParameters(true), false);
                Console.WriteLine("Plain Text: {0}", ByteConverter.GetString(dataToEncrypt));
                Console.WriteLine("Encrypted plaintext: {0}", ByteConverter.GetString(encryptedData));
                Console.WriteLine("Decrypted plaintext: {0}", ByteConverter.GetString(decryptedData));
            }
        }
        catch (ArgumentNullException)
        {
            //Catch this exception in case the encryption did
            //not succeed.
            Console.WriteLine("Encryption failed.");
        }
    }

    static public byte[] RSAEncrypt(byte[] DataToEncrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
    {
        byte[] encryptedData;
        using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
        {
            RSA.ImportParameters(RSAKeyInfo);
            encryptedData = RSA.Encrypt(DataToEncrypt, DoOAEPPadding);
        }
        return encryptedData;
    }

    static public byte[] RSADecrypt(byte[] DataToDecrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
    {
        byte[] decryptedData;
        using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
        {
            RSA.ImportParameters(RSAKeyInfo);
            decryptedData = RSA.Decrypt(DataToDecrypt, DoOAEPPadding);
        }
        return decryptedData;
    }
}

For more information Visit:
1. http://msdn.microsoft.com/en-us/library/system.security.cryptography.aes.aspx[^]

2. http://msdn.microsoft.com/en-us/library/system.security.cryptography.rsacryptoserviceprovider.aspx[^]