Sendin ID parameter in encrypted form

You can use AES algorithm for this. Example:

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

public class SampleClass
{
    private string secretKey = "mySecretKey12345";
    private string iv = "1234567890123456";

    public void GetHelpVideo(int ID)
    {
        // Encrypt the ID parameter
        byte[] idBytes = BitConverter.GetBytes(ID);
        Aes aesAlg = Aes.Create();
        aesAlg.Key = Encoding.UTF8.GetBytes(secretKey);
        aesAlg.IV = Encoding.UTF8.GetBytes(iv);
        MemoryStream msEncrypt = new MemoryStream();
        CryptoStream csEncrypt = new CryptoStream(msEncrypt, aesAlg.CreateEncryptor(), CryptoStreamMode.Write);
        csEncrypt.Write(idBytes, 0, idBytes.Length);
        csEncrypt.FlushFinalBlock();
        csEncrypt.Close();
        string encryptedID = Convert.ToBase64String(msEncrypt.ToArray());

        // Use the encrypted ID to retrieve the HelpContent object
        HelpContent obj = db.HelpContents.Find(DecryptID(encryptedID));

        // ...
    }

    private int DecryptID(string encryptedID)
    {
        // Decrypt the encrypted ID
        byte[] encryptedIdBytes = Convert.FromBase64String(encryptedID);
        Aes aesAlg = Aes.Create();
        aesAlg.Key = Encoding.UTF8.GetBytes(secretKey);
        aesAlg.IV = Encoding.UTF8.GetBytes(iv);
        MemoryStream msDecrypt = new MemoryStream(encryptedIdBytes);
        CryptoStream csDecrypt = new CryptoStream(msDecrypt, aesAlg.CreateDecryptor(), CryptoStreamMode.Read);
        byte[] idBytes = new byte[4];
        csDecrypt.Read(idBytes, 0, idBytes.Length);
        int id = BitConverter.ToInt32(idBytes, 0);
        return id;
    }
}

Thanks