C#里的一些加密解密标准函数示例—

C#里的一些加密解密标准函数示例——DES，SHA1，RSA

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发布时间：2019-06-09

本文共 10043 字，大约阅读时间需要 33 分钟。

最近收到了很多朋友的来信说希望提供DES的C#代码，但是我个人认为，.NET 提供了很多标准函数，没有必要自己写，所以我也只发布了C++的代码，如果大家一定要熟悉加密过程的话，也可以自己动手实现整个过程，这个可以参考我博客里的DES 算法介绍，和yxyDES2 Class的代码，代码注释相当的清楚。

　　.NET 提供了很多标准加密、解密函数，我简要介绍一下DES，SHA1，RSA的标准函数的使用。如果你想做一个网络安全模块，只需将三种算法结合起来设计一个模型，我相信可以实现很多复杂的功能。

　　示例本身并不复杂，我也不做过多解释，我也学Linus Torvalds一样吼一句："Read the f**ing code”，哈哈，开个玩笑，我相信大家肯定能看懂。

注：以下示例需引用命名空间： using System.Security.Cryptography;

一. DES 加密、解密

　　我相信一下注释相当清楚了，加上我博客里关于DES的文章确实不少，所以DES不做任何解释，怎么调用就更不用解释了吧，呵呵：

//默认密钥向量        private byte[] Keys = { 0xEF, 0xAB, 0x56, 0x78, 0x90, 0x34, 0xCD, 0x12 };        ///         /// DES加密字符串        /// 
        /// 待加密的字符串        /// 加密密钥,要求为8位        /// 
      
       加密成功返回加密后的字符串，失败返回源串
              public string EncryptDES(string encryptString, string encryptKey)        {            try            {                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));                byte[] rgbIV = Keys;                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();                MemoryStream mStream = new MemoryStream();                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);                cStream.Write(inputByteArray, 0, inputByteArray.Length);                cStream.FlushFinalBlock();                return Convert.ToBase64String(mStream.ToArray());            }            catch            {                return encryptString;            }        }        ///         /// DES解密字符串        /// 
        /// 待解密的字符串        /// 解密密钥,要求为8位,和加密密钥相同        /// 
      
       解密成功返回解密后的字符串，失败返源串
              public string DecryptDES(string decryptString, string decryptKey)        {            try            {                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey.Substring(0, 8));                byte[] rgbIV = Keys;                byte[] inputByteArray = Convert.FromBase64String(decryptString);                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();                MemoryStream mStream = new MemoryStream();                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);                cStream.Write(inputByteArray, 0, inputByteArray.Length);                cStream.FlushFinalBlock();                return Encoding.UTF8.GetString(mStream.ToArray());            }            catch            {                return decryptString;            }        }

二. SHA1 加密（HASH算法没有解密）

　　安全哈希算法（ Secure Hash Algorithm ）主要适用于数字签名标准（ Digital Signature Standard DSS ）里面定义的数字签名算法（ Digital Signature Algorithm DSA ）。对于长度小于 2^64 位的消息， SHA1 会产生一个 160 位的消息摘要。当接收到消息的时候，这个消息摘要可以用来验证数据的完整性。在传输的过程中，数据很可能会发生变化，那么这时候就会产生不同的消息摘要。

SHA1有如下特性：不可以从消息摘要中复原信息；两个不同的消息不会产生同样的消息摘要。

代码如下：

///         /// use sha1 to encrypt string        /// 
        public string SHA1_Encrypt(string Source_String)        {            byte[] StrRes = Encoding.Default.GetBytes(Source_String);            HashAlgorithm iSHA = new SHA1CryptoServiceProvider();            StrRes = iSHA.ComputeHash(StrRes);            StringBuilder EnText = new StringBuilder();            foreach (byte iByte in StrRes)            {                EnText.AppendFormat("{0:x2}", iByte);            }            return EnText.ToString();        }

三.RSA 加密、解密（本例来自 MSDN）

　　RSA加密算法是一种非对称加密算法。在公钥加密标准和电子商业中RSA被广泛使用。RSA是1977年由罗纳德·李维斯特（Ron Rivest）、阿迪·萨莫尔（Adi Shamir）和伦纳德·阿德曼（Leonard Adleman）一起提出的。当时他们三人都在麻省理工学院工作。RSA就是他们三人姓氏开头字母拼在一起组成的。

　　RSA算法的可靠性基于分解极大的整数是很困难的。假如有人找到一种很快的分解因子的算法的话，那么用RSA加密的信息的可靠性就肯定会极度下降。但找到这样的算法的可能性是非常小的。今天只有短的RSA钥匙才可能被强力方式解破。到2008年为止，世界上还没有任何可靠的攻击RSA算法的方式。只要其钥匙的长度足够长，用RSA加密的信息实际上是不能被解破的。

　　具体算法过程请参考

　　代码示例如下（来自MSDN）：

using System;using System.Security.Cryptography;using System.IO; using System.Text;namespace Microsoft.Samples.Security.PublicKey{  class App  {    // Main entry point    static void Main(string[] args)    {      // Instantiate 3 People for example. See the Person class below      Person alice = new Person("Alice");      Person bob = new Person("Bob");      Person steve = new Person("Steve");      // Messages that will exchanged. See CipherMessage class below      CipherMessage aliceMessage;      CipherMessage bobMessage;      CipherMessage steveMessage;      // Example of encrypting/decrypting your own message      Console.WriteLine("Encrypting/Decrypting Your Own Message");      Console.WriteLine("-----------------------------------------");      // Alice encrypts a message using her own public key      aliceMessage = alice.EncryptMessage("Alice wrote this message");      // then using her private key can decrypt the message      alice.DecryptMessage(aliceMessage);      // Example of Exchanging Keys and Messages      Console.WriteLine();      Console.WriteLine("Exchanging Keys and Messages");      Console.WriteLine("-----------------------------------------");      // Alice Sends a copy of her public key to Bob and Steve      bob.GetPublicKey(alice);      steve.GetPublicKey(alice);      // Bob and Steve both encrypt messages to send to Alice      bobMessage = bob.EncryptMessage("Hi Alice! - Bob.");      steveMessage = steve.EncryptMessage("How are you? - Steve");      // Alice can decrypt and read both messages      alice.DecryptMessage(bobMessage);      alice.DecryptMessage(steveMessage);      Console.WriteLine();      Console.WriteLine("Private Key required to read the messages");      Console.WriteLine("-----------------------------------------");      // Steve cannot read the message that Bob encrypted      steve.DecryptMessage(bobMessage);      // Not even Bob can use the Message he encrypted for Alice.      // The RSA private key is required to decrypt the RS2 key used      // in the decryption.      bob.DecryptMessage(bobMessage);    } // method Main  } // class App  class CipherMessage  {    public byte[] cipherBytes;  // RC2 encrypted message text    public byte[] rc2Key;       // RSA encrypted rc2 key    public byte[] rc2IV;        // RC2 initialization vector  }  class Person  {    private RSACryptoServiceProvider rsa;    private RC2CryptoServiceProvider rc2;    private string name;    // Maximum key size for the RC2 algorithm    const int keySize = 128;    // Person constructor    public Person(string p_Name)    {      rsa = new RSACryptoServiceProvider();      rc2 = new RC2CryptoServiceProvider();      rc2.KeySize = keySize;      name = p_Name;    }    // Used to send the rsa public key parameters    public RSAParameters SendPublicKey()     {      RSAParameters result = new RSAParameters();      try       {        result = rsa.ExportParameters(false);      }      catch (CryptographicException e)      {        Console.WriteLine(e.Message);      }      return result;    }    // Used to import the rsa public key parameters    public void GetPublicKey(Person receiver)    {      try       {        rsa.ImportParameters(receiver.SendPublicKey());       }      catch (CryptographicException e)      {        Console.WriteLine(e.Message);      }    }    public CipherMessage EncryptMessage(string text)    {      // Convert string to a byte array      CipherMessage message = new CipherMessage();      byte[] plainBytes = Encoding.Unicode.GetBytes(text.ToCharArray());      // A new key and iv are generated for every message      rc2.GenerateKey();      rc2.GenerateIV();      // The rc2 initialization doesnt need to be encrypted, but will      // be used in conjunction with the key to decrypt the message.      message.rc2IV = rc2.IV;      try       {        // Encrypt the RC2 key using RSA encryption        message.rc2Key = rsa.Encrypt(rc2.Key, false);      }      catch (CryptographicException e)      {        // The High Encryption Pack is required to run this  sample        // because we are using a 128-bit key. See the readme for        // additional information.        Console.WriteLine("Encryption Failed. Ensure that the" +           " High Encryption Pack is installed.");        Console.WriteLine("Error Message: " + e.Message);        Environment.Exit(0);      }      // Encrypt the Text Message using RC2 (Symmetric algorithm)      ICryptoTransform sse = rc2.CreateEncryptor();      MemoryStream ms = new MemoryStream();      CryptoStream cs = new CryptoStream(ms, sse, CryptoStreamMode.Write);      try      {          cs.Write(plainBytes, 0, plainBytes.Length);          cs.FlushFinalBlock();          message.cipherBytes = ms.ToArray();      }      catch (Exception e)      {          Console.WriteLine(e.Message);      }           finally      {        ms.Close();        cs.Close();      }      return message;    } // method EncryptMessage    public void DecryptMessage(CipherMessage message)    {      // Get the RC2 Key and Initialization Vector      rc2.IV = message.rc2IV;      try       {        // Try decrypting the rc2 key        rc2.Key = rsa.Decrypt(message.rc2Key, false);      }      catch (CryptographicException e)      {        Console.WriteLine("Decryption Failed: " + e.Message);        return;      }            ICryptoTransform ssd = rc2.CreateDecryptor();      // Put the encrypted message in a memorystream      MemoryStream ms = new MemoryStream(message.cipherBytes);      // the CryptoStream will read cipher text from the MemoryStream      CryptoStream cs = new CryptoStream(ms, ssd, CryptoStreamMode.Read);      byte[] initialText = new Byte[message.cipherBytes.Length];      try      {          // Decrypt the message and store in byte array          cs.Read(initialText, 0, initialText.Length);      }      catch (Exception e)      {          Console.WriteLine(e.Message);      }            finally       {        ms.Close();        cs.Close();      }      // Display the message received      Console.WriteLine(name + " received the following message:");      Console.WriteLine("  " + Encoding.Unicode.GetString(initialText));    } // method DecryptMessage  } // class Person} // namespace PublicKey

转载于:https://www.cnblogs.com/Ruiky/archive/2012/04/16/2451677.html

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