Encrypt and decrypt any text

TextEncryptor

using System;
using System.Collections.Generic;
using System.Text;

namespace Task_7_Encryption
{
class Encryption
{
static void Main()
{

    string message = "Write a program that encodes and decodes a string using given encryption key (cipher).";
    string key = "key";

    Console.WriteLine(Encrypt(message, key));
    Console.WriteLine();
    Console.WriteLine(Decrypt(Encrypt(message,key), key));
    Console.WriteLine();
}
static string Encrypt(string message, string key)
{
    var encryptedMessage = new StringBuilder(message.Length);

    for (int i = 0; i < message.Length; i++)
        encryptedMessage.Append((char)(message[i] ^ key[i % key.Length]));

    return encryptedMessage.ToString();
}

static string Decrypt(string message, string key)
{
    return Encrypt(message, key);
}
}
}