using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;

namespace GummingCommon
{
    public class Encryption
    {
        /// <summary> 
        /// 使用缺省密钥字符串加密 
        /// </summary> 
        /// <param name="original">明文</param> 
        /// <returns>密文</returns> 
        public static string Encrypt(string original)
        {
            return Encrypt(original, "KennethYao");
        }
        /// <summary> 
        /// 使用缺省密钥解密 
        /// </summary> 
        /// <param name="original">密文</param> 
        /// <returns>明文</returns> 
        public static string Decrypt(string original)
        {
            return Decrypt(original, "KennethYao", System.Text.Encoding.Default);
        }

        /// <summary> 
        /// 使用给定密钥解密 
        /// </summary> 
        /// <param name="original">密文</param> 
        /// <param name="key">密钥</param> 
        /// <returns>明文</returns> 
        public static string Decrypt(string original, string key)
        {
            return Decrypt(original, key, System.Text.Encoding.Default);
        }

        /// <summary> 
        /// 使用缺省密钥解密,返回指定编码方式明文 
        /// </summary> 
        /// <param name="original">密文</param> 
        /// <param name="encoding">编码方式</param> 
        /// <returns>明文</returns> 
        public static string Decrypt(string original, System.Text.Encoding encoding)
        {
            return Decrypt(original, "KennethYao", encoding);
        }

        /// <summary> 
        /// 使用给定密钥加密 
        /// </summary> 
        /// <param name="original">原始文字</param> 
        /// <param name="key">密钥</param> 
        /// <param name="encoding">字符编码方案</param> 
        /// <returns>密文</returns> 
        public static string Encrypt(string original, string key)
        {
            byte[] buff = System.Text.Encoding.Default.GetBytes(original);
            byte[] kb = System.Text.Encoding.Default.GetBytes(key);
            return Convert.ToBase64String(Encrypt(buff, kb));
        }

        /// <summary> 
        /// 使用给定密钥解密 
        /// </summary> 
        /// <param name="encrypted">密文</param> 
        /// <param name="key">密钥</param> 
        /// <param name="encoding">字符编码方案</param> 
        /// <returns>明文</returns> 
        public static string Decrypt(string encrypted, string key, System.Text.Encoding encoding)
        {
            try
            {
                byte[] buff = Convert.FromBase64String(encrypted);
                byte[] kb = System.Text.Encoding.Default.GetBytes(key);
                return encoding.GetString(Decrypt(buff, kb));
            }
            catch
            {
                return string.Empty;
            }
        }

        /// <summary> 
        /// 生成MD5摘要 
        /// </summary> 
        /// <param name="original">数据源</param> 
        /// <returns>摘要</returns> 
        public static byte[] MakeMD5(byte[] original)
        {
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            byte[] keyhash = hashmd5.ComputeHash(original);
            hashmd5 = null;
            return keyhash;
        }

        /// <summary> 
        /// 使用给定密钥加密 
        /// </summary> 
        /// <param name="original">明文</param> 
        /// <param name="key">密钥</param> 
        /// <returns>密文</returns> 
        public static byte[] Encrypt(byte[] original, byte[] key)
        {
            TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
            des.Key = MakeMD5(key);
            des.Mode = CipherMode.ECB;

            return des.CreateEncryptor().TransformFinalBlock(original, 0, original.Length);
        }

        /// <summary> 
        /// 使用给定密钥解密数据 
        /// </summary> 
        /// <param name="encrypted">密文</param> 
        /// <param name="key">密钥</param> 
        /// <returns>明文</returns> 
        public static byte[] Decrypt(byte[] encrypted, byte[] key)
        {
            TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
            des.Key = MakeMD5(key);
            des.Mode = CipherMode.ECB;

            return des.CreateDecryptor().TransformFinalBlock(encrypted, 0, encrypted.Length);
        }

        /// <summary> 
        /// 使用给定密钥加密 
        /// </summary> 
        /// <param name="original">原始数据</param> 
        /// <param name="key">密钥</param> 
        /// <returns>密文</returns> 
        public static byte[] Encrypt(byte[] original)
        {
            byte[] key = System.Text.Encoding.Default.GetBytes("KennethYao");
            return Encrypt(original, key);
        }

        /// <summary> 
        /// 使用缺省密钥解密数据 
        /// </summary> 
        /// <param name="encrypted">密文</param> 
        /// <param name="key">密钥</param> 
        /// <returns>明文</returns> 
        public static byte[] Decrypt(byte[] encrypted)
        {
            byte[] key = System.Text.Encoding.Default.GetBytes("KennethYao");
            return Decrypt(encrypted, key);
        }

        public static string GetMD5(string encypStr, string charset)
        {
            string retStr;
            MD5CryptoServiceProvider m5 = new MD5CryptoServiceProvider();

            //创建md5对象
            byte[] inputBye;
            byte[] outputBye;

            //使用GB2312编码方式把字符串转化为字节数组．
            try
            {
                inputBye = Encoding.GetEncoding(charset).GetBytes(encypStr);
            }
            catch (Exception ex)
            {
                inputBye = Encoding.GetEncoding("GB2312").GetBytes(encypStr);
            }
            outputBye = m5.ComputeHash(inputBye);

            retStr = System.BitConverter.ToString(outputBye);
            retStr = retStr.Replace("-", "").ToUpper();
            return retStr;
        }
    }
}