C#/.NET字符串加密和解密實現(AES和RSA代碼舉例)

在不少C#項目中,都須要實現對字符串的加密和解密，那麼如何實現呢？如今對稱密鑰加密中最流行的就是AES加密法。

密碼學中的高級加密標準（Advanced Encryption Standard，AES），又稱Rijndael加密法，是美國聯邦政府採用的一種區塊加密標準。這個標準用來替代原先的DES，已經被多方分析且廣爲全世界所使用。通過五年的甄選流程，高級加密標準由美國國家標準與技術研究院 （NIST）於2001年11月26日發佈於FIPS PUB 197，並在2002年5月26日成爲有效的標準。2006年，高級加密標準已然成爲對稱密鑰加密中最流行的算法之一。

  在這裏能夠提供一個基於AES加密和解密的實現代碼:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118

public  class  Crypto {      private  static  byte [] _salt = Encoding.ASCII.GetBytes( "o6806642kbM7c5" );      /// <summary>      /// Encrypt the given string using AES.  The string can be decrypted using      /// DecryptStringAES().  The sharedSecret parameters must match.      /// </summary>      /// <param name="plainText">The text to encrypt.</param>      /// <param name="sharedSecret">A password used to generate a key for encryption.</param>      public  static  string  EncryptStringAES( string  plainText,  string  sharedSecret)      {          if  ( string .IsNullOrEmpty(plainText))              throw  new  ArgumentNullException( "plainText" );          if  ( string .IsNullOrEmpty(sharedSecret))              throw  new  ArgumentNullException( "sharedSecret" );          string  outStr =  null ;                        // Encrypted string to return          RijndaelManaged aesAlg =  null ;               // RijndaelManaged object used to encrypt the data.          try          {              // generate the key from the shared secret and the salt              Rfc2898DeriveBytes key =  new  Rfc2898DeriveBytes(sharedSecret, _salt);              // Create a RijndaelManaged object              aesAlg =  new  RijndaelManaged();              aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);              // Create a decryptor to perform the stream transform.              ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);              // Create the streams used for encryption.              using  (MemoryStream msEncrypt =  new  MemoryStream())              {                  // prepend the IV                  msEncrypt.Write(BitConverter.GetBytes(aesAlg.IV.Length), 0,  sizeof ( int ));                  msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);                  using  (CryptoStream csEncrypt =  new  CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))                  {                      using  (StreamWriter swEncrypt =  new  StreamWriter(csEncrypt))                      {                          //Write all data to the stream.                          swEncrypt.Write(plainText);                      }                  }                  outStr = Convert.ToBase64String(msEncrypt.ToArray());              }          }          finally          {              // Clear the RijndaelManaged object.              if  (aesAlg !=  null )                  aesAlg.Clear();          }          // Return the encrypted bytes from the memory stream.          return  outStr;      }      /// <summary>      /// Decrypt the given string.  Assumes the string was encrypted using      /// EncryptStringAES(), using an identical sharedSecret.      /// </summary>      /// <param name="cipherText">The text to decrypt.</param>      /// <param name="sharedSecret">A password used to generate a key for decryption.</param>      public  static  string  DecryptStringAES( string  cipherText,  string  sharedSecret)      {          if  ( string .IsNullOrEmpty(cipherText))              throw  new  ArgumentNullException( "cipherText" );          if  ( string .IsNullOrEmpty(sharedSecret))              throw  new  ArgumentNullException( "sharedSecret" );          // Declare the RijndaelManaged object          // used to decrypt the data.          RijndaelManaged aesAlg =  null ;          // Declare the string used to hold          // the decrypted text.          string  plaintext =  null ;          try          {              // generate the key from the shared secret and the salt              Rfc2898DeriveBytes key =  new  Rfc2898DeriveBytes(sharedSecret, _salt);              // Create the streams used for decryption.                            byte [] bytes = Convert.FromBase64String(cipherText);              using  (MemoryStream msDecrypt =  new  MemoryStream(bytes))              {                  // Create a RijndaelManaged object                  // with the specified key and IV.                  aesAlg =  new  RijndaelManaged();                  aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);                  // Get the initialization vector from the encrypted stream                  aesAlg.IV = ReadByteArray(msDecrypt);                  // Create a decrytor to perform the stream transform.                  ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);                  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();                  }              }          }          finally          {              // Clear the RijndaelManaged object.              if  (aesAlg !=  null )                  aesAlg.Clear();          }          return  plaintext;      }      private  static  byte [] ReadByteArray(Stream s)      {          byte [] rawLength =  new  byte [ sizeof ( int )];          if  (s.Read(rawLength, 0, rawLength.Length) != rawLength.Length)          {              throw  new  SystemException( "Stream did not contain properly formatted byte array" );          }          byte [] buffer =  new  byte [BitConverter.ToInt32(rawLength, 0)];          if  (s.Read(buffer, 0, buffer.Length) != buffer.Length)          {              throw  new  SystemException( "Did not read byte array properly" );          }          return  buffer;      } }

   另外再提供一段基於RSA的加密算法,RSA公鑰加密算法是1977年由Ron Rivest、Adi Shamirh和LenAdleman在（美國麻省理工學院）開發的。RSA取名來自開發他們三者的名字。RSA是目前最有影響力的公鑰加密算法，它可以抵抗到目前爲止已知的全部密碼攻擊，已被ISO推薦爲公鑰數據加密標準。RSA算法基於一個十分簡單的數論事實：將兩個大素數相乘十分容易，但那時想要對其乘積進行因式分解卻極其困難，所以能夠將乘積公開做爲加密密鑰。

C#中實現RSA加密代碼以下:

1 2 3 4 5 6

var  provider =  new  System.Security.Cryptography.RSACryptoServiceProvider(); provider.ImportParameters(your_rsa_key); var  encryptedBytes = provider.Encrypt(      System.Text.Encoding.UTF8.GetBytes( "Hello World!" ),  true ); string  decryptedTest = System.Text.Encoding.UTF8.GetString(      provider.Decrypt(encryptedBytes,  true ));

轉載請註明：文章轉載自:[169IT-最新最全的IT資訊]
本文標題:C#/.NET字符串加密和解密實現(AES和RSA代碼舉例)