Utilisation du cryptage AES en C#

Question

Je n'arrive pas à trouver un bon exemple d'utilisation du cryptage AES 128 bits.

Est-ce que quelqu'un a un exemple de code?

Answer 1

Si vous voulez juste utiliser le haut-fournisseur de Crypto RijndaelManaged, consultez l'article d'aide suivante (il a également un simple exemple de code):

http://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged.aspx

Et juste Si vous avez besoin de l'échantillon pressé, ici il est dans toute sa gloire plagié:

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

namespace RijndaelManaged_Example 
{ 
    class RijndaelExample 
    { 
     public static void Main() 
     { 
      try 
      { 

       string original = "Here is some data to encrypt!"; 

       // Create a new instance of the RijndaelManaged 
       // class. This generates a new key and initialization 
       // vector (IV). 
       using (RijndaelManaged myRijndael = new RijndaelManaged()) 
       { 

        myRijndael.GenerateKey(); 
        myRijndael.GenerateIV(); 
        // Encrypt the string to an array of bytes. 
        byte[] encrypted = EncryptStringToBytes(original, myRijndael.Key, myRijndael.IV); 

        // Decrypt the bytes to a string. 
        string roundtrip = DecryptStringFromBytes(encrypted, myRijndael.Key, myRijndael.IV); 

        //Display the original data and the decrypted data. 
        Console.WriteLine("Original: {0}", original); 
        Console.WriteLine("Round Trip: {0}", roundtrip); 
       } 

      } 
      catch (Exception e) 
      { 
       Console.WriteLine("Error: {0}", e.Message); 
      } 
     } 
     static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV) 
     { 
      // Check arguments. 
      if (plainText == null || plainText.Length <= 0) 
       throw new ArgumentNullException("plainText"); 
      if (Key == null || Key.Length <= 0) 
       throw new ArgumentNullException("Key"); 
      if (IV == null || IV.Length <= 0) 
       throw new ArgumentNullException("IV"); 
      byte[] encrypted; 
      // Create an RijndaelManaged object 
      // with the specified key and IV. 
      using (RijndaelManaged rijAlg = new RijndaelManaged()) 
      { 
       rijAlg.Key = Key; 
       rijAlg.IV = IV; 

       // Create a decryptor to perform the stream transform. 
       ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.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 encrypted; 

     } 

     static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV) 
     { 
      // Check arguments. 
      if (cipherText == null || cipherText.Length <= 0) 
       throw new ArgumentNullException("cipherText"); 
      if (Key == null || Key.Length <= 0) 
       throw new ArgumentNullException("Key"); 
      if (IV == null || IV.Length <= 0) 
       throw new ArgumentNullException("IV"); 

      // Declare the string used to hold 
      // the decrypted text. 
      string plaintext = null; 

      // Create an RijndaelManaged object 
      // with the specified key and IV. 
      using (RijndaelManaged rijAlg = new RijndaelManaged()) 
      { 
       rijAlg.Key = Key; 
       rijAlg.IV = IV; 

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

       // Create the streams used for decryption. 
       using (MemoryStream msDecrypt = new MemoryStream(cipherText)) 
       { 
        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; 

     } 
    } 
} 

Answer 2

en utilisant AES ou la mise en œuvre AES? Pour utiliser AES, il existe la classe System.Security.Cryptography.RijndaelManaged.

Answer 3

Pour un exemple plus complet qui effectue une dérivation de clé en plus du chiffrement AES, voir la réponse et les liens publiés dans Getting AES encryption to work across Javascript and C#.

EDIT
une note de côté: Javascript Cryptography considered harmful. vaut la lecture.

Answer 4

Regardez échantillon ici ..

http://msdn.microsoft.com/en-us/library/system.security.cryptography.rijndaelmanaged(v=VS.100).aspx#Y2262

L'exemple sur MSDN ne fonctionne pas normalement (une erreur se produit) parce qu'il n'y a pas valeur initiale de Initial Vector (iv) et Clé. J'ajoute 2 lignes de code et maintenant je travaille normalement.

Plus de détails voir ci-dessous:

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

namespace AES_TESTER 
{ 
    public partial class Form1 : Form 
    { 
     public Form1() 
     { 
      InitializeComponent(); 
     } 

     private void Form1_Load(object sender, EventArgs e) 
     { 
      try 
      { 

      string original = "Here is some data to encrypt!"; 
      MessageBox.Show("Original: " + original); 

      // Create a new instance of the RijndaelManaged 
      // class. This generates a new key and initialization 
      // vector (IV). 
      using (RijndaelManaged myRijndael = new RijndaelManaged()) 
      { 
       myRijndael.GenerateKey(); 
       myRijndael.GenerateIV(); 

       // Encrypt the string to an array of bytes. 
       byte[] encrypted = EncryptStringToBytes(original, myRijndael.Key, myRijndael.IV); 

       StringBuilder s = new StringBuilder(); 
       foreach (byte item in encrypted) 
       { 
        s.Append(item.ToString("X2") + " "); 
       } 
       MessageBox.Show("Encrypted: " + s); 

       // Decrypt the bytes to a string. 
       string decrypted = DecryptStringFromBytes(encrypted, myRijndael.Key, myRijndael.IV); 

       //Display the original data and the decrypted data. 
       MessageBox.Show("Decrypted: " + decrypted); 
      } 

     } 
     catch (Exception ex) 
     { 
      MessageBox.Show("Error: {0}", ex.Message); 
     } 
    } 

    static byte[] EncryptStringToBytes(string plainText, byte[] Key, byte[] IV) 
    { 
     // Check arguments. 
     if (plainText == null || plainText.Length <= 0) 
      throw new ArgumentNullException("plainText"); 
     if (Key == null || Key.Length <= 0) 
      throw new ArgumentNullException("Key"); 
     if (IV == null || IV.Length <= 0) 
      throw new ArgumentNullException("Key"); 
     byte[] encrypted; 
     // Create an RijndaelManaged object 
     // with the specified key and IV. 
     using (RijndaelManaged rijAlg = new RijndaelManaged()) 
     { 
      rijAlg.Key = Key; 
      rijAlg.IV = IV; 
      rijAlg.Mode = CipherMode.CBC; 
      rijAlg.Padding = PaddingMode.Zeros; 

      // Create a decrytor to perform the stream transform. 
      ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.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 encrypted; 

    } 

    static string DecryptStringFromBytes(byte[] cipherText, byte[] Key, byte[] IV) 
    { 
     // Check arguments. 
     if (cipherText == null || cipherText.Length <= 0) 
      throw new ArgumentNullException("cipherText"); 
     if (Key == null || Key.Length <= 0) 
      throw new ArgumentNullException("Key"); 
     if (IV == null || IV.Length <= 0) 
      throw new ArgumentNullException("Key"); 

     // Declare the string used to hold 
     // the decrypted text. 
     string plaintext = null; 

     // Create an RijndaelManaged object 
     // with the specified key and IV. 
     using (RijndaelManaged rijAlg = new RijndaelManaged()) 
     { 
      rijAlg.Key = Key; 
      rijAlg.IV = IV; 
      rijAlg.Mode = CipherMode.CBC; 
      rijAlg.Padding = PaddingMode.Zeros; 

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

      // Create the streams used for decryption. 
      using (MemoryStream msDecrypt = new MemoryStream(cipherText)) 
      { 
       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; 
    } 
    } 
} 

Answer 5

Essayez ce code, peut-être utile.
1.Créez Nouveau projet C# et ajouter suit le code à Form1:

using System; 
using System.Windows.Forms; 
using System.Security.Cryptography; 

namespace ExampleCrypto 
{ 
    public partial class Form1 : Form 
    { 
     public Form1() 
     { 
      InitializeComponent(); 
     } 

     private void Form1_Load(object sender, EventArgs e) 
     { 
      string strOriginalData = string.Empty; 
      string strEncryptedData = string.Empty; 
      string strDecryptedData = string.Empty; 

      strOriginalData = "this is original data 1234567890"; // your original data in here 
      MessageBox.Show("ORIGINAL DATA:\r\n" + strOriginalData); 

      clsCrypto aes = new clsCrypto(); 
      aes.IV = "this is your IV";  // your IV 
      aes.KEY = "this is your KEY"; // your KEY  
      strEncryptedData = aes.Encrypt(strOriginalData, CipherMode.CBC); // your cipher mode 
      MessageBox.Show("ENCRYPTED DATA:\r\n" + strEncryptedData); 

      strDecryptedData = aes.Decrypt(strEncryptedData, CipherMode.CBC); 
      MessageBox.Show("DECRYPTED DATA:\r\n" + strDecryptedData); 
     } 

    } 
} 

2.Créez clsCrypto.cs et copier coller le code suit dans votre classe et exécutez votre code. J'ai utilisé MD5 pour générer Initial Vector (IV) et KEY of AES.

using System; 
using System.Security.Cryptography; 
using System.Text; 
using System.Windows.Forms; 
using System.IO; 
using System.Runtime.Remoting.Metadata.W3cXsd2001; 

namespace ExampleCrypto 
{ 
    public class clsCrypto 
    { 
     private string _KEY = string.Empty; 
     protected internal string KEY 
     { 
      get 
      { 
       return _KEY; 
      } 
      set 
      { 
       if (!string.IsNullOrEmpty(value)) 
       { 
        _KEY = value; 
       } 
      } 
     } 

     private string _IV = string.Empty; 
     protected internal string IV 
     { 
      get 
      { 
       return _IV; 
      } 
      set 
      { 
       if (!string.IsNullOrEmpty(value)) 
       { 
        _IV = value; 
       } 
      } 
     } 

     private string CalcMD5(string strInput) 
     { 
      string strOutput = string.Empty; 
      if (!string.IsNullOrEmpty(strInput)) 
      { 
       try 
       { 
        StringBuilder strHex = new StringBuilder(); 
        using (MD5 md5 = MD5.Create()) 
        { 
         byte[] bytArText = Encoding.Default.GetBytes(strInput); 
         byte[] bytArHash = md5.ComputeHash(bytArText); 
         for (int i = 0; i < bytArHash.Length; i++) 
         { 
          strHex.Append(bytArHash[i].ToString("X2")); 
         } 
         strOutput = strHex.ToString(); 
        } 
       } 
       catch (Exception ex) 
       { 
        MessageBox.Show(ex.Message); 
       } 
      } 
      return strOutput; 
     } 

     private byte[] GetBytesFromHexString(string strInput) 
     { 
      byte[] bytArOutput = new byte[] { }; 
      if ((!string.IsNullOrEmpty(strInput)) && strInput.Length % 2 == 0) 
      { 
       SoapHexBinary hexBinary = null; 
       try 
       { 
        hexBinary = SoapHexBinary.Parse(strInput); 
       } 
       catch (Exception ex) 
       { 
        MessageBox.Show(ex.Message); 
       } 
       bytArOutput = hexBinary.Value; 
      } 
      return bytArOutput; 
     } 

     private byte[] GenerateIV() 
     { 
      byte[] bytArOutput = new byte[] { }; 
      try 
      { 
       string strIV = CalcMD5(IV); 
       bytArOutput = GetBytesFromHexString(strIV); 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
      return bytArOutput; 
     } 

     private byte[] GenerateKey() 
     { 
      byte[] bytArOutput = new byte[] { }; 
      try 
      { 
       string strKey = CalcMD5(KEY); 
       bytArOutput = GetBytesFromHexString(strKey); 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
      return bytArOutput; 
     } 

     protected internal string Encrypt(string strInput, CipherMode cipherMode) 
     { 
      string strOutput = string.Empty; 
      if (!string.IsNullOrEmpty(strInput)) 
      { 
       try 
       { 
        byte[] bytePlainText = Encoding.Default.GetBytes(strInput); 
        using (RijndaelManaged rijManaged = new RijndaelManaged()) 
        { 
         rijManaged.Mode = cipherMode; 
         rijManaged.BlockSize = 128; 
         rijManaged.KeySize = 128; 
         rijManaged.IV = GenerateIV(); 
         rijManaged.Key = GenerateKey(); 
         rijManaged.Padding = PaddingMode.Zeros; 
         ICryptoTransform icpoTransform = rijManaged.CreateEncryptor(rijManaged.Key, rijManaged.IV); 
         using (MemoryStream memStream = new MemoryStream()) 
         { 
          using (CryptoStream cpoStream = new CryptoStream(memStream, icpoTransform, CryptoStreamMode.Write)) 
          { 
           cpoStream.Write(bytePlainText, 0, bytePlainText.Length); 
           cpoStream.FlushFinalBlock(); 
          } 
          strOutput = Encoding.Default.GetString(memStream.ToArray()); 
         } 
        } 
       } 
       catch (Exception ex) 
       { 
        MessageBox.Show(ex.Message); 
       } 
      } 
      return strOutput; 
     } 

     protected internal string Decrypt(string strInput, CipherMode cipherMode) 
     { 
      string strOutput = string.Empty; 
      if (!string.IsNullOrEmpty(strInput)) 
      { 
       try 
       { 
        byte[] byteCipherText = Encoding.Default.GetBytes(strInput); 
        byte[] byteBuffer = new byte[strInput.Length]; 
        using (RijndaelManaged rijManaged = new RijndaelManaged()) 
        { 
         rijManaged.Mode = cipherMode; 
         rijManaged.BlockSize = 128; 
         rijManaged.KeySize = 128; 
         rijManaged.IV = GenerateIV(); 
         rijManaged.Key = GenerateKey(); 
         rijManaged.Padding = PaddingMode.Zeros; 
         ICryptoTransform icpoTransform = rijManaged.CreateDecryptor(rijManaged.Key, rijManaged.IV); 
         using (MemoryStream memStream = new MemoryStream(byteCipherText)) 
         { 
          using (CryptoStream cpoStream = new CryptoStream(memStream, icpoTransform, CryptoStreamMode.Read)) 
          { 
           cpoStream.Read(byteBuffer, 0, byteBuffer.Length); 
          } 
          strOutput = Encoding.Default.GetString(byteBuffer); 
         } 
        } 
       } 
       catch (Exception ex) 
       { 
        MessageBox.Show(ex.Message); 
       } 
      } 
      return strOutput; 
     } 

    } 
} 

Answer 6

J'ai récemment dû buter contre ce nouveau dans mon propre projet - et je voulais partager le code un peu plus simple que je l'ai utilisé, comme cette question et une série de réponses à venir dans maintenues mon recherches.

Je ne vais pas entrer dans les problèmes de sécurité autour de la fréquence de mise à jour des choses comme votre sel et Initialization Vector - c'est un sujet pour un forum de sécurité, et il y a quelques grandes ressources là-bas pour regarder à. C'est simplement un bloc de code à implémenter AesManaged en C#.

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

namespace Your.Namespace.Security { 
    public static class Cryptography { 
     #region Settings 

     private static int _iterations = 2; 
     private static int _keySize = 256; 

     private static string _hash  = "SHA1"; 
     private static string _salt  = "aselrias38490a32"; // Random 
     private static string _vector = "8947az34awl34kjq"; // Random 

     #endregion 

     public static string Encrypt(string value, string password) { 
      return Encrypt<AesManaged>(value, password); 
     } 
     public static string Encrypt<T>(string value, string password) 
       where T : SymmetricAlgorithm, new() { 
      byte[] vectorBytes = GetBytes<ASCIIEncoding>(_vector); 
      byte[] saltBytes = GetBytes<ASCIIEncoding>(_salt); 
      byte[] valueBytes = GetBytes<UTF8Encoding>(value); 

      byte[] encrypted; 
      using (T cipher = new T()) { 
       PasswordDeriveBytes _passwordBytes = 
        new PasswordDeriveBytes(password, saltBytes, _hash, _iterations); 
       byte[] keyBytes = _passwordBytes.GetBytes(_keySize/8); 

       cipher.Mode = CipherMode.CBC; 

       using (ICryptoTransform encryptor = cipher.CreateEncryptor(keyBytes, vectorBytes)) { 
        using (MemoryStream to = new MemoryStream()) { 
         using (CryptoStream writer = new CryptoStream(to, encryptor, CryptoStreamMode.Write)) { 
          writer.Write(valueBytes, 0, valueBytes.Length); 
          writer.FlushFinalBlock(); 
          encrypted = to.ToArray(); 
         } 
        } 
       } 
       cipher.Clear(); 
      } 
      return Convert.ToBase64String(encrypted); 
     } 

     public static string Decrypt(string value, string password) { 
      return Decrypt<AesManaged>(value, password); 
     } 
     public static string Decrypt<T>(string value, string password) where T : SymmetricAlgorithm, new() { 
      byte[] vectorBytes = GetBytes<ASCIIEncoding>(_vector); 
      byte[] saltBytes = GetBytes<ASCIIEncoding>(_salt); 
      byte[] valueBytes = Convert.FromBase64String(value); 

      byte[] decrypted; 
      int decryptedByteCount = 0; 

      using (T cipher = new T()) { 
       PasswordDeriveBytes _passwordBytes = new PasswordDeriveBytes(password, saltBytes, _hash, _iterations); 
       byte[] keyBytes = _passwordBytes.GetBytes(_keySize/8); 

       cipher.Mode = CipherMode.CBC; 

       try { 
        using (ICryptoTransform decryptor = cipher.CreateDecryptor(keyBytes, vectorBytes)) { 
         using (MemoryStream from = new MemoryStream(valueBytes)) { 
          using (CryptoStream reader = new CryptoStream(from, decryptor, CryptoStreamMode.Read)) { 
           decrypted = new byte[valueBytes.Length]; 
           decryptedByteCount = reader.Read(decrypted, 0, decrypted.Length); 
          } 
         } 
        } 
       } catch (Exception ex) { 
        return String.Empty; 
       } 

       cipher.Clear(); 
      } 
      return Encoding.UTF8.GetString(decrypted, 0, decryptedByteCount); 
     } 

    } 
} 

Le code est très simple à utiliser.Il faut littéralement ce qui suit:

string encrypted = Cryptography.Encrypt(data, "testpass"); 
string decrypted = Cryptography.Decrypt(encrypted, "testpass"); 

Par défaut, la mise en œuvre utilise AesManaged - mais vous pouvez réellement insérer aussi tout autre SymmetricAlgorithm. Une liste des disponibles pour SymmetricAlgorithm 4,5 .NET héritières se trouve à l'adresse:

http://msdn.microsoft.com/en-us/library/system.security.cryptography.symmetricalgorithm.aspx

Au moment de ce poste, la liste actuelle comprend:

• AesManaged
• RijndaelManaged
• DESCryptoServiceProvider
• RC2CryptoServiceProvider
• TripleDESCryptoServiceProvider

Pour utiliser RijndaelManaged avec le code ci-dessus, à titre d'exemple, vous utilisez:

string encrypted = Cryptography.Encrypt<RijndaelManaged>(dataToEncrypt, password); 
string decrypted = Cryptography.Decrypt<RijndaelManaged>(encrypted, password); 

J'espère que cela est utile à quelqu'un là-bas.

Answer 7

Vous pouvez utiliser le mot de passe de la boîte de texte comme clé ... Avec ce code, vous pouvez crypter/décrypter le texte, image, document word, pdf ....

public class Rijndael 
{ 
    private byte[] key; 
    private readonly byte[] vector = { 255, 64, 191, 111, 23, 3, 113, 119, 231, 121, 252, 112, 79, 32, 114, 156 }; 

    ICryptoTransform EnkValue, DekValue; 

    public Rijndael(byte[] key) 
    { 
     this.key = key; 
     RijndaelManaged rm = new RijndaelManaged(); 
     rm.Padding = PaddingMode.PKCS7; 
     EnkValue = rm.CreateEncryptor(key, vector); 
     DekValue = rm.CreateDecryptor(key, vector); 
    } 

    public byte[] Encrypt(byte[] byte) 
    { 

     byte[] enkByte= byte; 
     byte[] enkNewByte; 
     using (MemoryStream ms = new MemoryStream()) 
     { 
      using (CryptoStream cs = new CryptoStream(ms, EnkValue, CryptoStreamMode.Write)) 
      { 
       cs.Write(enkByte, 0, enkByte.Length); 
       cs.FlushFinalBlock(); 

       ms.Position = 0; 
       enkNewByte= new byte[ms.Length]; 
       ms.Read(enkNewByte, 0, enkNewByte.Length); 
      } 
     } 
     return enkNeyByte; 
    } 

    public byte[] Dekrypt(byte[] enkByte) 
    { 
     byte[] dekByte; 
     using (MemoryStream ms = new MemoryStream()) 
     { 
      using (CryptoStream cs = new CryptoStream(ms, DekValue, CryptoStreamMode.Write)) 
      { 
       cs.Write(enkByte, 0, enkByte.Length); 
       cs.FlushFinalBlock(); 

       ms.Position = 0; 
       dekByte= new byte[ms.Length]; 
       ms.Read(dekByte, 0, dekByte.Length); 
      } 
     } 
     return dekByte; 
    } 
} 

mot de passe Convertir de zone de texte tableau d'octets ...

private byte[] ConvertPasswordToByte(string password) 
    { 
     byte[] key = new byte[32]; 
     for (int i = 0; i < passwprd.Length; i++) 
     { 
      key[i] = Convert.ToByte(passwprd[i]); 
     } 
     return key; 
    } 

Answer 8

//Code to encrypt Data : 
public byte[] encryptdata(byte[] bytearraytoencrypt, string key, string iv) 
     { 
      AesCryptoServiceProvider dataencrypt = new AesCryptoServiceProvider(); 
      //Block size : Gets or sets the block size, in bits, of the cryptographic operation. 
      dataencrypt.BlockSize = 128; 
      //KeySize: Gets or sets the size, in bits, of the secret key 
      dataencrypt.KeySize = 128; 
      //Key: Gets or sets the symmetric key that is used for encryption and decryption. 
      dataencrypt.Key = System.Text.Encoding.UTF8.GetBytes(key); 
      //IV : Gets or sets the initialization vector (IV) for the symmetric algorithm 
      dataencrypt.IV = System.Text.Encoding.UTF8.GetBytes(iv); 
      //Padding: Gets or sets the padding mode used in the symmetric algorithm 
      dataencrypt.Padding = PaddingMode.PKCS7; 
      //Mode: Gets or sets the mode for operation of the symmetric algorithm 
      dataencrypt.Mode = CipherMode.CBC; 
      //Creates a symmetric AES encryptor object using the current key and initialization vector (IV). 
      ICryptoTransform crypto1 = dataencrypt.CreateEncryptor(dataencrypt.Key, dataencrypt.IV); 
      //TransformFinalBlock is a special function for transforming the last block or a partial block in the stream. 
      //It returns a new array that contains the remaining transformed bytes. A new array is returned, because the amount of 
      //information returned at the end might be larger than a single block when padding is added. 
      byte[] encrypteddata = crypto1.TransformFinalBlock(bytearraytoencrypt, 0, bytearraytoencrypt.Length); 
      crypto1.Dispose(); 
      //return the encrypted data 
      return encrypteddata; 
     } 

//code to decrypt data 
    private byte[] decryptdata(byte[] bytearraytodecrypt, string key, string iv) 
    { 

     AesCryptoServiceProvider keydecrypt = new AesCryptoServiceProvider(); 
     keydecrypt.BlockSize = 128; 
     keydecrypt.KeySize = 128; 
     keydecrypt.Key = System.Text.Encoding.UTF8.GetBytes(key); 
     keydecrypt.IV = System.Text.Encoding.UTF8.GetBytes(iv); 
     keydecrypt.Padding = PaddingMode.PKCS7; 
     keydecrypt.Mode = CipherMode.CBC; 
     ICryptoTransform crypto1 = keydecrypt.CreateDecryptor(keydecrypt.Key, keydecrypt.IV); 

     byte[] returnbytearray = crypto1.TransformFinalBlock(bytearraytodecrypt, 0, bytearraytodecrypt.Length); 
     crypto1.Dispose(); 
     return returnbytearray; 
    } 

Answer 9

est ici un code propre et propre à comprendre l'algorithme AES 256 implémenté en C# appel Crypter fonction encryptedstring = cryptObj.Encrypt(username, "AGARAMUDHALA", "EZHUTHELLAM", "SHA1", 3, "@1B2c3D4e5F6g7H8", 256);

public class Crypt 
{ 
    public string Encrypt(string passtext, string passPhrase, string saltV, string hashstring, int Iterations, string initVect, int keysize) 
    { 
     string functionReturnValue = null; 
     // Convert strings into byte arrays. 
     // Let us assume that strings only contain ASCII codes. 
     // If strings include Unicode characters, use Unicode, UTF7, or UTF8 
     // encoding. 
     byte[] initVectorBytes = null; 
     initVectorBytes = Encoding.ASCII.GetBytes(initVect); 
     byte[] saltValueBytes = null; 
     saltValueBytes = Encoding.ASCII.GetBytes(saltV); 

     // Convert our plaintext into a byte array. 
     // Let us assume that plaintext contains UTF8-encoded characters. 
     byte[] plainTextBytes = null; 
     plainTextBytes = Encoding.UTF8.GetBytes(passtext); 
     // First, we must create a password, from which the key will be derived. 
     // This password will be generated from the specified passphrase and 
     // salt value. The password will be created using the specified hash 
     // algorithm. Password creation can be done in several iterations. 
     PasswordDeriveBytes password = default(PasswordDeriveBytes); 
     password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashstring, Iterations); 
     // Use the password to generate pseudo-random bytes for the encryption 
     // key. Specify the size of the key in bytes (instead of bits). 
     byte[] keyBytes = null; 
     keyBytes = password.GetBytes(keysize/8); 
     // Create uninitialized Rijndael encryption object. 
     RijndaelManaged symmetricKey = default(RijndaelManaged); 
     symmetricKey = new RijndaelManaged(); 

     // It is reasonable to set encryption mode to Cipher Block Chaining 
     // (CBC). Use default options for other symmetric key parameters. 
     symmetricKey.Mode = CipherMode.CBC; 
     // Generate encryptor from the existing key bytes and initialization 
     // vector. Key size will be defined based on the number of the key 
     // bytes. 
     ICryptoTransform encryptor = default(ICryptoTransform); 
     encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes); 

     // Define memory stream which will be used to hold encrypted data. 
     MemoryStream memoryStream = default(MemoryStream); 
     memoryStream = new MemoryStream(); 

     // Define cryptographic stream (always use Write mode for encryption). 
     CryptoStream cryptoStream = default(CryptoStream); 
     cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write); 
     // Start encrypting. 
     cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length); 

     // Finish encrypting. 
     cryptoStream.FlushFinalBlock(); 
     // Convert our encrypted data from a memory stream into a byte array. 
     byte[] cipherTextBytes = null; 
     cipherTextBytes = memoryStream.ToArray(); 

     // Close both streams. 
     memoryStream.Close(); 
     cryptoStream.Close(); 

     // Convert encrypted data into a base64-encoded string. 
     string cipherText = null; 
     cipherText = Convert.ToBase64String(cipherTextBytes); 

     functionReturnValue = cipherText; 
     return functionReturnValue; 
    } 
    public string Decrypt(string cipherText, string passPhrase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize) 
    { 
     string functionReturnValue = null; 

     // Convert strings defining encryption key characteristics into byte 
     // arrays. Let us assume that strings only contain ASCII codes. 
     // If strings include Unicode characters, use Unicode, UTF7, or UTF8 
     // encoding. 


      byte[] initVectorBytes = null; 
      initVectorBytes = Encoding.ASCII.GetBytes(initVector); 

      byte[] saltValueBytes = null; 
      saltValueBytes = Encoding.ASCII.GetBytes(saltValue); 

      // Convert our ciphertext into a byte array. 
      byte[] cipherTextBytes = null; 
      cipherTextBytes = Convert.FromBase64String(cipherText); 

      // First, we must create a password, from which the key will be 
      // derived. This password will be generated from the specified 
      // passphrase and salt value. The password will be created using 
      // the specified hash algorithm. Password creation can be done in 
      // several iterations. 
      PasswordDeriveBytes password = default(PasswordDeriveBytes); 
      password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations); 

      // Use the password to generate pseudo-random bytes for the encryption 
      // key. Specify the size of the key in bytes (instead of bits). 
      byte[] keyBytes = null; 
      keyBytes = password.GetBytes(keySize/8); 

      // Create uninitialized Rijndael encryption object. 
      RijndaelManaged symmetricKey = default(RijndaelManaged); 
      symmetricKey = new RijndaelManaged(); 

      // It is reasonable to set encryption mode to Cipher Block Chaining 
      // (CBC). Use default options for other symmetric key parameters. 
      symmetricKey.Mode = CipherMode.CBC; 

      // Generate decryptor from the existing key bytes and initialization 
      // vector. Key size will be defined based on the number of the key 
      // bytes. 
      ICryptoTransform decryptor = default(ICryptoTransform); 
      decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes); 

      // Define memory stream which will be used to hold encrypted data. 
      MemoryStream memoryStream = default(MemoryStream); 
      memoryStream = new MemoryStream(cipherTextBytes); 

      // Define memory stream which will be used to hold encrypted data. 
      CryptoStream cryptoStream = default(CryptoStream); 
      cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read); 

      // Since at this point we don't know what the size of decrypted data 
      // will be, allocate the buffer long enough to hold ciphertext; 
      // plaintext is never longer than ciphertext. 
      byte[] plainTextBytes = null; 
      plainTextBytes = new byte[cipherTextBytes.Length + 1]; 

      // Start decrypting. 
      int decryptedByteCount = 0; 
      decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length); 

      // Close both streams. 
      memoryStream.Close(); 
      cryptoStream.Close(); 

      // Convert decrypted data into a string. 
      // Let us assume that the original plaintext string was UTF8-encoded. 
      string plainText = null; 
      plainText = Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount); 

      // Return decrypted string. 
      functionReturnValue = plainText; 


     return functionReturnValue; 
    } 
} 

Answer 10

http://www.codeproject.com/Articles/769741/Csharp-AES-bits-Encryption-Library-with-Salt

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

public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes) 
{ 
    byte[] encryptedBytes = null; 
    byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 }; 
    using (MemoryStream ms = new MemoryStream()) 
    { 
     using (RijndaelManaged AES = new RijndaelManaged()) 
     { 
      AES.KeySize = 256; 
      AES.BlockSize = 128; 
      var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000); 
      AES.Key = key.GetBytes(AES.KeySize/8); 
      AES.IV = key.GetBytes(AES.BlockSize/8); 
      AES.Mode = CipherMode.CBC; 
      using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write)) 
      { 
       cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length); 
       cs.Close(); 
      } 
      encryptedBytes = ms.ToArray(); 
     } 
    } 
    return encryptedBytes; 
} 

public byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes) 
{ 
    byte[] decryptedBytes = null; 
    byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 }; 
    using (MemoryStream ms = new MemoryStream()) 
    { 
     using (RijndaelManaged AES = new RijndaelManaged()) 
     { 
      AES.KeySize = 256; 
      AES.BlockSize = 128; 
      var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000); 
      AES.Key = key.GetBytes(AES.KeySize/8); 
      AES.IV = key.GetBytes(AES.BlockSize/8); 
      AES.Mode = CipherMode.CBC; 
      using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write)) 
      { 
       cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length); 
       cs.Close(); 
      } 
      decryptedBytes = ms.ToArray(); 
     } 
    } 
    return decryptedBytes; 
}