Encryption and Decryption (Cryptography) in C#

Application level encryption and decryption is needed for certain cases when security is applied. It can simply be user credentials or even may be user specific data. Anyway, it is a good way or using a unique encryption and decryption method across the application.

Cryptography is widely used by almost all the developers and it is not that hard to have a common EncryptionUtility for your own application. Look at the sample class below;

 public class EncryptionUtility  
   {  
     static readonly string PasswordHash = "Z!R3cVwPa_b7^5TZ!_rE";  
     static readonly string SaltKey = "&7fHXcc2^$8x@AwrdC$c";  
     static readonly string VIKey = "6=ZvwA##4Ms3*yV2D&6$";  
     //Encryption method  
     public static string Encrypt(string plainText)  
     {  
       try  
       {  
         byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);  
         byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);  
         var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.Zeros };  
         var encryptor = symmetricKey.CreateEncryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));  
         byte[] cipherTextBytes;  
         using (var memoryStream = new MemoryStream())  
         {  
           using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))  
           {  
             cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);  
             cryptoStream.FlushFinalBlock();  
             cipherTextBytes = memoryStream.ToArray();  
             cryptoStream.Close();  
           }  
           memoryStream.Close();  
         }  
         return Convert.ToBase64String(cipherTextBytes);  
       }  
       catch (Exception)  
       {  
         //You can use your own error handling method. In this case, the text is returned.  
         return plainText;  
       }  
     }  
     //Decryption method  
     public static string Decrypt(string encryptedText)  
     {  
       try  
       {  
         byte[] cipherTextBytes = Convert.FromBase64String(encryptedText);  
         byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);  
         var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.None };  
         var decryptor = symmetricKey.CreateDecryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));  
         var memoryStream = new MemoryStream(cipherTextBytes);  
         var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);  
         byte[] plainTextBytes = new byte[cipherTextBytes.Length];  
         int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);  
         memoryStream.Close();  
         cryptoStream.Close();  
         return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount).TrimEnd("\0".ToCharArray());  
       }  
       catch (Exception)  
       {  
         return encryptedText;  
       }  
     }  
     //Method to see a given text is encrypted or not.  
     public static bool IsEncrypted(string text)  
     {  
       if (text.Equals(Decrypt(text)))  
         return false;  
       else  
         return true;  
     }  
   }  

Because the methods are defined as static, you can use it as below;

 EncryptionUtility.Encrypt(username)  

Copy this code and try once. :)