C#DES加密解密编码格式小结

在网上也看了一点别人写的DES加密和解密算法：列举如下

       public static string Encode(string str, string key)         {             DESCryptoServiceProvider provider = new DESCryptoServiceProvider();             provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));             provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));             byte[] bytes = Encoding.UTF8.GetBytes(str);             MemoryStream stream = new MemoryStream();             CryptoStream stream2 = new CryptoStream(stream, provider.CreateEncryptor(), CryptoStreamMode.Write);             stream2.Write(bytes, 0, bytes.Length);             stream2.FlushFinalBlock();             StringBuilder builder = new StringBuilder();             foreach (byte num in stream.ToArray())             {                 builder.AppendFormat("{0:X2}", num);             }             stream.Close();             return builder.ToString();         }

解密：

public static string Decode(string str, string key)          {              DESCryptoServiceProvider provider = new DESCryptoServiceProvider();             provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));             provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));             byte[] buffer = new byte[str.Length / 2];             for (int i = 0; i < (str.Length / 2); i++)             {                 int num2 = Convert.ToInt32(str.Substring(i * 2, 2), 0x10);                 buffer[i] = (byte)num2;             }             MemoryStream stream = new MemoryStream();             CryptoStream stream2 = new CryptoStream(stream, provider.CreateDecryptor(), CryptoStreamMode.Write);             stream2.Write(buffer, 0, buffer.Length);             stream2.FlushFinalBlock();             stream.Close();             return Encoding.GetEncoding("GB2312").GetString(stream.ToArray());         } 

注意：上面方法中的key采用都是ASCII编码格式，如果我们用Base64生成key进行解码的时候就会提示Key长度不符合要求，这个情况下，我们就需要将key截取8位进行重新验证，问题解决，无编码错误......