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

namespace ZJ_BYD.Untils
{
    public static class DesHelper
    {
        //例
        // string resule = EncryptDES( "这是一个测试字符串！！",  "temp" );
        //Console.WriteLine( resule );  //输出 UQYZz2CHw06AYY4YoySTiefE1KY3JE0XBOpe65PeUF8=
        //Console.WriteLine( DecryptDES( resule, "temp" ) ); //输出 这是一个测试字符串！！


        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="plainText"></param>
        /// <param name="Key"></param>
        /// <returns></returns>
        public static string EncryptStringToBytes_Aes(string plainText, string Key)
        {
            //取 32 位 key
            Key = Key.PadLeft(32, '0').Substring(0, 32);
            //设置加密的 key，其值来自参数
            byte[] key = Encoding.UTF8.GetBytes(Key);
            var IV = Key.PadLeft(16, '0').Substring(0, 16);
            //设置加密的 iv 向量，这里使用硬编码演示
            byte[] iv = Encoding.UTF8.GetBytes(IV);//"temp" 

            byte[] encrypted;

            // Create an Aes object
            // with the specified key and IV.
            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = key;
                aesAlg.IV = iv;

                // Create an encryptor to perform the stream transform.
                ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

                // Create the streams used for encryption.
                using (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                        {
                            //Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }
                        encrypted = msEncrypt.ToArray();
                    }
                }
            }
            // Return the encrypted bytes from the memory stream.
            return Convert.ToBase64String(encrypted);

        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="cipherText"></param>
        /// <param name="Key"></param>
        /// <returns></returns>
        public static string DecryptStringFromBytes_Aes(string cipherText, string Key)
        {
            try
            {
                //取 32 位 key
                Key = Key.PadLeft(32, '0').Substring(0, 32);
                //设置加密的 key，其值来自参数
                byte[] key = Encoding.UTF8.GetBytes(Key);
                var IV = Key.PadLeft(16, '0').Substring(0, 16);
                //设置加密的 iv 向量，这里使用硬编码演示
                byte[] iv = Encoding.UTF8.GetBytes(IV);//"temp" 

                byte[] context = Convert.FromBase64String(cipherText);
                // Declare the string used to hold
                // the decrypted text.
                string plaintext = null;

                // Create an Aes object
                // with the specified key and IV.
                using (Aes aesAlg = Aes.Create())
                {
                    aesAlg.Key = key;
                    aesAlg.IV = iv;

                    // Create a decryptor to perform the stream transform.
                    ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

                    // Create the streams used for decryption.
                    using (MemoryStream msDecrypt = new MemoryStream(context))
                    {
                        using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                        {
                            using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                            {

                                // Read the decrypted bytes from the decrypting stream
                                // and place them in a string.
                                plaintext = srDecrypt.ReadToEnd();
                            }
                        }
                    }
                }
                return plaintext;
            }
            catch (Exception)
            {
                return "";
            }
        }
    }
}