How to encrypt and decrypt a string in C#? Need easy method with example

Here are the working methods with sample output for encryption and decryption of string in C#

Encryption Method in C#

public string Encrypt(string secureUserData , bool useHashing)
{
    byte[] keyArray;
    byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(secureUserData );
    string key = string.Empty;
    byte[] resultArray;
 
      // Get the key from Web.Config file
    //key = ConfigurationManager.AppSettings.Get("EncKey");
    key ="MAKV2SPBNI99212";
     

    if (useHashing)
    {

        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
        hashmd5.Clear();

    }
    else
    {
        keyArray = UTF8Encoding.UTF8.GetBytes(key);
    }

    TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
    tdes.Key = keyArray;
    tdes.Mode = CipherMode.ECB;
    tdes.Padding = PaddingMode.PKCS7;
 
    ICryptoTransform cTransform = tdes.CreateEncryptor();

    resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

    tdes.Clear();

    return Convert.ToBase64String(resultArray, 0, resultArray.Length);
}

Decryption method in C#

public string Decrypt(string cipherString, bool useHashing)
{
    byte[] keyArray;
    byte[] toEncryptArray = Convert.FromBase64String(cipherString);
    byte[] resultArray;
    string key = string.Empty;

    //key = ConfigurationManager.AppSettings.Get("SecurityKey"); 
    key ="MAKV2SPBNI99212";
 

    if (useHashing)
    {
        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
        hashmd5.Clear();
    }
    else
    {
        keyArray = UTF8Encoding.UTF8.GetBytes(key);
    }

    TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
    tdes.Key = keyArray;
    tdes.Mode = CipherMode.ECB;
    tdes.Padding = PaddingMode.PKCS7;

 
    ICryptoTransform cTransform = tdes.CreateDecryptor();
    resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);


    tdes.Clear();
 

    return UTF8Encoding.UTF8.GetString(resultArray);

}

Complete C# Console app code for encryption and decryption

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

namespace EncryptDecryptCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            string UserDataKeyTosecure = "12121";
            //Encrypting data using Hashing
            var cipherString = Encrypt(UserDataKeyTosecure, true);
            Console.WriteLine("Encrypted key : "+ cipherString);

            //Decrypt data using Hashing by passing above cipherString
            var DecryptedKey = Decrypt(cipherString, true);

            Console.WriteLine("Decrypted key : " + DecryptedKey);
        }
        public static string Encrypt(string secureUserData, bool useHashing)
        {
            byte[] keyArray;
            byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(secureUserData);
            string key = string.Empty;
            byte[] resultArray;

            // Get the key from Web.Config file
            //key = ConfigurationManager.AppSettings.Get("EncKey");
            key = "MAKV2SPBNI99212";


            if (useHashing)
            {

                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                hashmd5.Clear();

            }
            else
            {
                keyArray = UTF8Encoding.UTF8.GetBytes(key);
            }

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            tdes.Key = keyArray;
            tdes.Mode = CipherMode.ECB;
            tdes.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = tdes.CreateEncryptor();

            resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

            tdes.Clear();

            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
        }

        public static string Decrypt(string cipherString, bool useHashing)
        {
            byte[] keyArray;
            byte[] toEncryptArray = Convert.FromBase64String(cipherString);
            byte[] resultArray;
            string key = string.Empty;

            //key = ConfigurationManager.AppSettings.Get("SecurityKey"); 
            key = "MAKV2SPBNI99212";


            if (useHashing)
            {
                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                hashmd5.Clear();
            }
            else
            {
                keyArray = UTF8Encoding.UTF8.GetBytes(key);
            }

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            tdes.Key = keyArray;
            tdes.Mode = CipherMode.ECB;
            tdes.Padding = PaddingMode.PKCS7;


            ICryptoTransform cTransform = tdes.CreateDecryptor();
            resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);


            tdes.Clear();


            return UTF8Encoding.UTF8.GetString(resultArray);

        }
    }
}

Here is the output of the above Code

Hope it helps.

Encryption is the process of translating plain text data (plaintext) into something that appears to be random and meaningless (ciphertext).It is used to transform a data into some un-readable form so that authenticated person only can read/access the data. It requires some secret information to transform the plain text to cipher text; it is usually referred as key.

Decryption is the process of converting ciphertext back to plaintext. To encrypt more than a small amount of data, symmetric encryption is used.

Here is the nice article which explains string encryption / decryption in c# with detail.