C# Online Compiler | .NET Fiddle

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

public class Program
{
	public static void Main()
	{
		// declaring key
		var key = "b14ca5898a4e4133bbce2ea2315a1916";
		
		// encrypt parameters
		var input = string.Concat("https://myDomain.in/", "Encrypt.aspx?query=", EncryptString(key, string.Format("emailID={0}", "myemail@gmail.com")));
		
		Console.WriteLine("Encrypted Input: " + input);
		
		// decrypt parameters
		var decrptedInput = DecryptString(key, input.Substring(input.IndexOf("=") + 1)); 
		Console.WriteLine("Decrypted Input: " + decrptedInput);
	}

	public static string EncryptString(string key, string plainInput)
	{
		byte[] iv = new byte[16];
		byte[] array;
		using (Aes aes = Aes.Create())
		{
			aes.Key = Encoding.UTF8.GetBytes(key);
			aes.IV = iv;
			ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
			using (MemoryStream memoryStream = new MemoryStream())
			{
				using (CryptoStream cryptoStream = new CryptoStream((Stream)memoryStream, encryptor, CryptoStreamMode.Write))
				{
					using (StreamWriter streamWriter = new StreamWriter((Stream)cryptoStream))
					{
						streamWriter.Write(plainInput);
					}

					array = memoryStream.ToArray();
				}
			}
		}

		return Convert.ToBase64String(array);
	}

	public static string DecryptString(string key, string cipherText)
	{
		byte[] iv = new byte[16];
		byte[] buffer = Convert.FromBase64String(cipherText);
		using (Aes aes = Aes.Create())
		{
			aes.Key = Encoding.UTF8.GetBytes(key);
			aes.IV = iv;
			ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);
			using (MemoryStream memoryStream = new MemoryStream(buffer))
			{
				using (CryptoStream cryptoStream = new CryptoStream((Stream)memoryStream, decryptor, CryptoStreamMode.Read))
				{
					using (StreamReader streamReader = new StreamReader((Stream)cryptoStream))
					{
						return streamReader.ReadToEnd();
					}
				}
			}
		}
	}
}

 
using System;
using System.Security.Cryptography;
using System.IO;
using System.Text;
​
public class Program
{
    public static void Main()
    {
        // declaring key
        var key = "b14ca5898a4e4133bbce2ea2315a1916";
        
        // encrypt parameters
        var input = string.Concat("https://myDomain.in/", "Encrypt.aspx?query=", EncryptString(key, string.Format("emailID={0}", "myemail@gmail.com")));
        
        Console.WriteLine("Encrypted Input: " + input);
        
        // decrypt parameters
        var decrptedInput = DecryptString(key, input.Substring(input.IndexOf("=") + 1)); 
        Console.WriteLine("Decrypted Input: " + decrptedInput);
    }
​
    public static string EncryptString(string key, string plainInput)
    {