赤痕：夜之仪式 某个武器描述的解密代码

bloodstained.cs

using System;
using System.Globalization;
using System.Linq;
using System.Text;
/// <summary>
/// 本程序意在对游戏 Bloodstained: Ritual of the Night 中出现的武器 Encrypted Orchid 的
/// 武器描述：
/// 
///          6F20636B6E7077206772646C7A207A77
///          6B6A207075707365756C2078726B7674
///          
/// 进行解密。直接将原文转写成ASCII值即可得到密文
/// 
/// 　　　　　o cknpw grdlz zwkj pupseul xrkvt
/// 　　　　　
/// 密文采用了维吉尼亚密码（https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher）进行加密，
/// 密匙已经在武器名中透露（orchid），依照此法解密后可得原文
/// 
///         a light saber with immense power
///         
/// </summary>
namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            string pwd = "6F20636B6E7077206772646C7A207A77" +
                         "6B6A207075707365756C2078726B7674";
            string key = "orchid";
            byte[] pwdArr = new byte[pwd.Length / 2];
            for (int i = 0; i < pwd.Length / 2; i++)
            {
                string s = new string(new char[2] { pwd[i * 2], pwd[i * 2 + 1] });
                pwdArr[i] = byte.Parse(s, NumberStyles.AllowHexSpecifier);
            }            
            string output_1 = Encoding.ASCII.GetString(pwdArr);
            string output_2 = output_1.Replace(" ", string.Empty);
            string output_3 = string.Empty;
            for (var i = 0; i < output_2.Length; i++)
            {
                char first = Convert.ToChar(key[i % key.Length]);
                output_3 += Caesar(first, output_2[i]);
            }
            int index = 0;
            foreach (int i in output_1.Split(' ').Select(i => i.Length))
            {
                index += i;
                output_3 = output_3.Insert(index, " ");
                index++;
            }
            Console.WriteLine(output_3);
            Console.ReadLine();
        }
        static char Caesar(char first, char cypher)
        {
            char offset = Convert.ToChar(first <= cypher ? cypher - first : 26 - first + cypher);
            return Convert.ToChar('a' + offset);
        }
    }
}