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

namespace langguanApi.Common
{
    /// <summary>
    /// 字符串处理类
    /// </summary>
    public static class StringHelper
    {
        /// <summary>
        /// MD5加密算法
        /// </summary>
        /// <param name="password"></param>
        /// <returns></returns>
        public static string MD5Encrypt32(string password)
        {
            string cl = password;
            string pwd = "";
            MD5 md5 = MD5.Create(); //实例化一个md5对像
                                    // 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择　
            byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl));
            // 通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得
            for (int i = 0; i < s.Length; i++)
            {
                // 将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母，如果使用大写（X）则格式后的字符是大写字符 
                pwd = pwd + s[i].ToString("X");
            }
            return pwd;
        }

        /// <summary>  
        /// 加密  
        /// </summary>  
        /// <param name="strSource">需要加密的字符串</param>  
        /// <returns>加密后的字符串</returns>  
        //[OperationContract]
        public static string Encrypt(string strSource)
        {
            //把字符串放到byte数组中  
            byte[] bytIn = System.Text.Encoding.Default.GetBytes(strSource);
            //建立加密对象的密钥和偏移量          
            byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定义偏移量  
            byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定义密钥  
            //实例DES加密类  
            DESCryptoServiceProvider mobjCryptoService = new DESCryptoServiceProvider();
            mobjCryptoService.Key = iv;
            mobjCryptoService.IV = key;
            ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
            //实例MemoryStream流加密密文件  
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
            cs.Write(bytIn, 0, bytIn.Length);
            cs.FlushFinalBlock();

            string strOut = System.Convert.ToBase64String(ms.ToArray());
            return strOut;

        }
        /// <summary>  
        /// 解密  
        /// </summary>  
        /// <param name="Source">需要解密的字符串</param>  
        /// <returns>解密后的字符串</returns>  
        //[OperationContract]
        public static string Decrypt(string Source)
        {
            if (Source == null) return string.Empty;
            //将解密字符串转换成字节数组  
            byte[] bytIn = System.Convert.FromBase64String(Source);
            //给出解密的密钥和偏移量，密钥和偏移量必须与加密时的密钥和偏移量相同  
            byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定义偏移量  
            byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定义密钥  
            DESCryptoServiceProvider mobjCryptoService = new DESCryptoServiceProvider();
            mobjCryptoService.Key = iv;
            mobjCryptoService.IV = key;
            //实例流进行解密  
            System.IO.MemoryStream ms = new System.IO.MemoryStream(bytIn, 0, bytIn.Length);
            ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
            CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
            StreamReader strd = new StreamReader(cs, Encoding.Default);
            return strd.ReadToEnd();
        }
    }
}