using System.IO;

using System.Security.Cryptography;

using System.Text;

using System;

​

public class Program

{

    public static string Encrypt(string plainText, string secretKey, CipherMode cipherMode = CipherMode.CFB)

    {

        // Validate input parameter

        if (plainText == null || plainText.Length <= 0)

        {

            throw new ArgumentNullException("plainText");

        }

​

        if (secretKey == null || secretKey.Length == 0)

        {

            throw new ArgumentNullException("secretKey");

        }

​

        byte[] key = Encoding.UTF8.GetBytes(secretKey);

        byte[] cipherText = Encoding.UTF8.GetBytes(plainText);

        // Initialize IV

        byte[] iv = new byte[16];

        Array.Copy(cipherText, 0, iv, 0, 16);

        using (Aes aes = Aes.Create())

        {

            aes.Mode = cipherMode;

            aes.Padding = PaddingMode.None;

            ICryptoTransform transform = aes.CreateEncryptor(key, iv);

            using MemoryStream memoryStream = new MemoryStream();

            // Write IV to output stream

            memoryStream.Write(iv, 0, 16);

            // Write encrypt content to output stream

            using CryptoStream stream = new CryptoStream(memoryStream, transform, CryptoStreamMode.Write);

            using (StreamWriter streamWriter = new StreamWriter(stream))

            {

                streamWriter.Write(plainText);

            }

​

            return Convert.ToBase64String(memoryStream.ToArray());

        }

    }

​

    public static void Main()

    {

        int seed = 1, increment = 3;

        int n = 1000;

        int x = seed;

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

        {

            x = (x + increment) % n;

            Console.WriteLine(x);

        }

    //string plaintext = "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";

    //Console.WriteLine(Encrypt(plaintext, "3baac2b6d3b80f8a507948b6f3a10733", CipherMode.CFB));

    }

}