using System;

using System.Security.Cryptography;

using System.Text;

public class Program

{

    public static void Main()

    {

        // Input data

        string pin = "1234";

        string pan = "5559405048128222";

        string pinEncryptionKey = "EEBD88FF1C4868E0BF72B75DC3844E16";

​

        // Step 1: Create the ISO-0 formatted PIN block

        // Format: 04 + PIN + Fill with F's to make it 16 hex characters

        string pinBlock = "04" + pin + "FFFFFFFFFF";

​

        // Step 2: Extract 12 right-most digits of PAN (excluding the check digit)

        string panBlock = "0000" + pan.Substring(pan.Length - 13, 12);

​

        // Step 3: XOR the PIN block with the PAN block

        byte[] pinBlockBytes = HexStringToBytes(pinBlock);

        byte[] panBlockBytes = HexStringToBytes(panBlock);

        byte[] xorResult = new byte[8];

        for (int i = 0; i < 8; i++)

        {

            xorResult[i] = (byte)(pinBlockBytes[i] ^ panBlockBytes[i]);

        }

​

        // Step 4: Encrypt the result with Triple DES using the provided key

        byte[] keyBytes = HexStringToBytes(pinEncryptionKey);

        byte[] encryptedPinBlock = Encrypt3DES(xorResult, keyBytes);

​

        // Output the encrypted PIN block in hexadecimal

        Console.WriteLine("Generated PIN Block (Encrypted): " + BitConverter.ToString(encryptedPinBlock).Replace("-", ""));

    }

    // Helper method to convert a hex string to a byte array

    static byte[] HexStringToBytes(string hex)

    {

        byte[] bytes = new byte[hex.Length / 2];

        for (int i = 0; i < hex.Length; i += 2)

        {

            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);

        }

        return bytes;

    }

​

    // Helper method for 3DES encryption

    static byte[] Encrypt3DES(byte[] data, byte[] key)

    {

        using (TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider())

        {

            tdes.Key = key;

            tdes.Mode = CipherMode.ECB;

            tdes.Padding = PaddingMode.None;

            using (ICryptoTransform encryptor = tdes.CreateEncryptor())

            {

                return encryptor.TransformFinalBlock(data, 0, data.Length);

            }

        }

    }

}