談談數據加密的處理--提供各種算法處理

作者: 伍華聰來源: 博客園發布時間: 2010-10-14 07:16 閱讀: 2650 次推薦: 0 原文鏈接 [收藏]

[1] 談談數據加密的處理--提供各種算法處理
[2] 談談數據加密的處理--提供各種算法處理
[3] 談談數據加密的處理--提供各種算法處理
[4] 談談數據加密的處理--提供各種算法處理

　　數據的加密重要性大家皆知，很多情況下需要對數據進行加密處理，但各種重要數據的加密要求不一樣，有些需要時可逆的，有些是不要求可逆的，可逆的一般稱之為對稱加密算法，不可逆的一般可以成為非對稱加密算法。如登錄密碼，一般較好的方式是采用不可逆的加密算法，如MD5、SHA256、哈希數值等，當然也有的采用可逆的強度好一些的加密方式，在選擇加密鍵值的時候，變化一下也算是比較不錯的選擇。另外一些為了掩人耳目或者不讓別人直接可以查看到，就采用其他的加密算法，如DES加密算法、AES的RijndaelManaged加密算法，或者也可以采用Base64加密，甚至我看到一個很變態的方式，就是用MD5加密的頭，內容則采用Base64的方式加密，一般不知道內情的還真的不好處理。

　　在吉日《[走火入魔失眠夜]淺談管理軟件信息安全，用戶名、密碼的加密解密【附C#配套加密解密源碼】》的文章中也對加密做了一些介紹和分析，并貼出了MD5、DES的加密方式代碼，吉日的文章圖文并茂、哲理及詼諧例子并存，本文有感而發，做一些補充，希望園子同行共通過切磋，交流心得。

　　加密字符串的方式有很多，也都可以通過這樣的加密文件內容，不過較好的方式可能是采用DES及AES兩種方式來加密文件了，下面貼出的代碼中包含了加解密文件的算法。下面具體貼出本人收藏的各種加密算法代碼。

　　1、DES加密字符串及文件等

　　如果想可逆的算法，這種方式一般不錯，只要結合動態密鑰，就可以做出強度比較高的加密應用了。

        public const string DEFAULT_ENCRYPT_KEY = "12345678";

        /// <summary>
        /// 使用默認加密
        /// </summary>
        /// <param name="strText"></param>
        /// <returns></returns>
        public static string DesEncrypt(string strText)
        {
            try
            {
                return DesEncrypt(strText, DEFAULT_ENCRYPT_KEY);
            }
            catch
            {
                return "";
            }
        }

        /// <summary>
        /// 使用默認解密
        /// </summary>
        /// <param name="strText"></param>
        /// <returns></returns>
        public static string DesDecrypt(string strText)
        {
            try
            {
                return DesDecrypt(strText, DEFAULT_ENCRYPT_KEY);
            }
            catch
            {
                return "";
            }
        }

        /// <summary>
        /// Encrypt the string
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="strText">string</param>
        /// <param name="strEncrKey">key</param>
        /// <returns></returns>
        public static string DesEncrypt(string strText, string strEncrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            byKey = Encoding.UTF8.GetBytes(strEncrKey.Substring(0, 8));
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.UTF8.GetBytes(strText);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            return Convert.ToBase64String(ms.ToArray());
        }

        /// <summary>
        /// Decrypt string
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="strText">Decrypt string</param>
        /// <param name="sDecrKey">key</param>
        /// <returns>output string</returns>
        public static string DesDecrypt(string strText, string sDecrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            byte[] inputByteArray = new Byte[strText.Length];

            byKey = Encoding.UTF8.GetBytes(sDecrKey.Substring(0, 8));
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            inputByteArray = Convert.FromBase64String(strText);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            Encoding encoding = new UTF8Encoding();
            return encoding.GetString(ms.ToArray());
        }

        /// <summary>
        /// Encrypt files
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="m_InFilePath">Encrypt file path</param>
        /// <param name="m_OutFilePath">output file</param>
        /// <param name="strEncrKey">key</param>
        public static void DesEncrypt(string m_InFilePath, string m_OutFilePath, string strEncrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            byKey = Encoding.UTF8.GetBytes(strEncrKey.Substring(0, 8));
            FileStream fin = new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
            FileStream fout = new FileStream(m_OutFilePath, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength(0);
            //Create variables to help with read and write.
            byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
            long rdlen = 0; //This is the total number of bytes written.
            long totlen = fin.Length; //This is the total length of the input file.
            int len; //This is the number of bytes to be written at a time.

            DES des = new DESCryptoServiceProvider();
            CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write);

            //Read from the input file, then encrypt and write to the output file.
            while (rdlen < totlen)
            {
                len = fin.Read(bin, 0, 100);
                encStream.Write(bin, 0, len);
                rdlen = rdlen + len;
            }
            encStream.Close();
            fout.Close();
            fin.Close();
        }

        /// <summary>
        /// Decrypt files
        /// Attention:key must be 8 bits
        /// </summary>
        /// <param name="m_InFilePath">Decrypt filepath</param>
        /// <param name="m_OutFilePath">output filepath</param>
        /// <param name="sDecrKey">key</param>
        public static void DesDecrypt(string m_InFilePath, string m_OutFilePath, string sDecrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            byKey = Encoding.UTF8.GetBytes(sDecrKey.Substring(0, 8));
            FileStream fin = new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
            FileStream fout = new FileStream(m_OutFilePath, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength(0);
            //Create variables to help with read and write.
            byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
            long rdlen = 0; //This is the total number of bytes written.
            long totlen = fin.Length; //This is the total length of the input file.
            int len; //This is the number of bytes to be written at a time.

            DES des = new DESCryptoServiceProvider();
            CryptoStream encStream = new CryptoStream(fout, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);

            //Read from the input file, then encrypt and write to the output file.
            while (rdlen < totlen)
            {
                len = fin.Read(bin, 0, 100);
                encStream.Write(bin, 0, len);
                rdlen = rdlen + len;
            }
            encStream.Close();
            fout.Close();
            fin.Close();
        }

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