Cryptography

If you are looking to encrypt/decrypt data, this is what I was able to put together from some other sites I found.

I am using GUIDs for both the Key and the Salt for the encryption, which I am getting from Unique IDs from within the data itself.

1. Add this code. I added it to a namespace of Customer.Business.Util

/// <summary>
/// Encrypt or Decrypt a String
/// </summary>
/// <param name="CryptType">(E)ncrypt or (D)ecrpt</param>
/// <param name="TextToConvert">The Text to be encrypted or decrypted.</param>
/// <param name="Key">The Key for encryption.</param>
/// <param name="IV">The Salt for encryption.</param>
/// <returns>The Text converted.</returns>
public static string CryptString(char CryptType, string TextToConvert, byte[] Key, byte[] IV)
{
    try
    {
        // Create a new instance of the RijndaelManaged
        // class.  This generates a new key and initialization 
        // vector (IV).
        RijndaelManaged myRijndael = new RijndaelManaged();
        // Change Key and Salt to user provided Key and Salt
        myRijndael.Key = Key;
        myRijndael.IV = IV;

        if (CryptType.ToString() == "D")
        { // decrypt
            return decryptString_AES(TextToConvert, myRijndael.Key, myRijndael.IV);
        }
        else
        { // encrypt
            return encryptString_AES(TextToConvert, myRijndael.Key, myRijndael.IV);
        }
    }
    catch (Exception e)
    {
        Console.WriteLine("Error: {0}", e.Message);
        return string.Empty;
    }
}

private static string encryptString_AES(string plainText, byte[] Key, byte[] IV)
{
    string encryptText = string.Empty;
    // Check arguments.
    if (plainText == null || plainText.Length <= 0)
        throw new ArgumentNullException("plainText");
    if (Key == null || Key.Length <= 0)
        throw new ArgumentNullException("Key");
    if (IV == null || IV.Length <= 0)
        throw new ArgumentNullException("Salt");

    // Declare the stream used to encrypt to an in memory
    // array of bytes.
    MemoryStream msEncrypt = null;

    // Declare the RijndaelManaged object
    // used to encrypt the data.
    RijndaelManaged aesAlg = null;

    try
    {
        // Create a RijndaelManaged object
        // with the specified key and IV.
        aesAlg = new RijndaelManaged();
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        // Create a decrytor to perform the stream transform.
        ICryptoTransform encryptor = aesAlg.CreateEncryptor(Key, IV);

        // Create the streams used for encryption.
        msEncrypt = new MemoryStream();
        using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
        {
            using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
            {
                //Write all data to the stream.
                swEncrypt.Write(plainText);
            }
        }
    }
    finally
    {
        // Clear the RijndaelManaged object.
        if (aesAlg != null)
            aesAlg.Clear();
    }
    // Return the encrypted bytes from the memory stream.
    byte[] b = msEncrypt.ToArray();
    encryptText = Convert.ToBase64String(b);
    return encryptText;
}

private static string decryptString_AES(string cipherText, byte[] Key, byte[] IV)
{
    // Check arguments.
    if (cipherText == null || cipherText.Length <= 0 || cipherText == string.Empty)
        throw new ArgumentNullException("cipherText");
    if (Key == null || Key.Length <= 0)
        throw new ArgumentNullException("Key");
    if (IV == null || IV.Length <= 0)
        throw new ArgumentNullException("Salt");

    //Convert to byte[]
    byte[] cipherByte = Convert.FromBase64String(cipherText.Trim());

    // Declare the RijndaelManaged object
    // used to decrypt the data.
            RijndaelManaged aesAlg = null;

    // Declare the string used to hold
    // the decrypted text.
    string plaintext = null;

    try
    {
        // Create a RijndaelManaged object
        // with the specified key and IV.
        aesAlg = new RijndaelManaged();
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        // Create a decrytor to perform the stream transform.
        ICryptoTransform decryptor = aesAlg.CreateDecryptor(Key, IV);
        // Create the streams used for decryption.
        using (MemoryStream msDecrypt = new MemoryStream(cipherByte))
        {
            using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
            {
                using (StreamReader srDecrypt = new StreamReader(csDecrypt))

                    // Read the decrypted bytes from the decrypting stream
                    // and place them in a string.
                    plaintext = srDecrypt.ReadToEnd();
            }
        }
    }
    finally
    {
        // Clear the RijndaelManaged object.
        if (aesAlg != null)
            aesAlg.Clear();
    }
    return plaintext;
}

2. Call the Method to Encrypt like this.

encryptedNumber = Customer.Business.Util.CryptString('E', Payment1.AccountNumber, OrderFormId.ToByteArray(), PaymentId.ToByteArray());

3. Call the same Method to Decrypt like this.

decryptedCode = Customer.Business.Util.CryptString('D', encryptedCode, OrderFormId.ToByteArray(), PaymentId.ToByteArray());