trunk/src/LythumOSL.Security/RijndaelSimple.cs
/// <summary>
/// Decrypts specified ciphertext using Rijndael symmetric key algorithm.
/// </summary>
/// <param name="cipherText">
/// Base64-formatted ciphertext value.
/// </param>
/// <param name="passPhrase">
/// Passphrase from which a pseudo-random password will be derived. The
/// derived password will be used to generate the encryption key.
/// Passphrase can be any string. In this example we assume that this
/// passphrase is an ASCII string.
/// </param>
/// <param name="saltValue">
/// Salt value used along with passphrase to generate password. Salt can
/// be any string. In this example we assume that salt is an ASCII string.
/// </param>
/// <param name="hashAlgorithm">
/// Hash algorithm used to generate password. Allowed values are: "MD5" and
/// "SHA1". SHA1 hashes are a bit slower, but more secure than MD5 hashes.
/// </param>
/// <param name="passwordIterations">
/// Number of iterations used to generate password. One or two iterations
/// should be enough.
/// </param>
/// <param name="initVector">
/// Initialization vector (or IV). This value is required to encrypt the
/// first block of plaintext data. For RijndaelManaged class IV must be
/// exactly 16 ASCII characters long.
/// </param>
/// <param name="keySize">
/// Size of encryption key in bits. Allowed values are: 128, 192, and 256.
/// Longer keys are more secure than shorter keys.
/// </param>
/// <returns>
/// Decrypted string value.
/// </returns>
/// <remarks>
/// Most of the logic in this function is similar to the Encrypt
/// logic. In order for decryption to work, all parameters of this function
/// - except cipherText value - must match the corresponding parameters of
/// the Encrypt function which was called to generate the
/// ciphertext.
/// </remarks>
Decrypts specified ciphertext using Rijndael symmetric key algorithm.
Decrypts specified ciphertext using Rijndael symmetric key algorithm .
public static string StaticDecrypt (string cipherText,
									 string passPhrase,
									 string saltValue,
									 string hashAlgorithm,
									 int passwordIterations,
									 string initVector,
									 int keySize)
		{
			byte[] initVectorBytes = Encoding.ASCII.GetBytes (initVector);
			byte[] saltValueBytes = Encoding.ASCII.GetBytes (saltValue);
			byte[] cipherTextBytes = Convert.FromBase64String (cipherText);
			PasswordDeriveBytes password = new PasswordDeriveBytes (
															passPhrase,
															saltValueBytes,
															hashAlgorithm,
															passwordIterations);
			byte[] keyBytes = password.GetBytes (keySize / 8);
			RijndaelManaged symmetricKey = new RijndaelManaged ();
			symmetricKey.Mode = CipherMode.CBC;
			ICryptoTransform decryptor = symmetricKey.CreateDecryptor (
															 keyBytes,
															 initVectorBytes);
			MemoryStream memoryStream = new MemoryStream (cipherTextBytes);
			CryptoStream cryptoStream = new CryptoStream (memoryStream,
														  decryptor,
														  CryptoStreamMode.Read);
			byte[] plainTextBytes = new byte[cipherTextBytes.Length];
			int decryptedByteCount = cryptoStream.Read (plainTextBytes,
													   0,
													   plainTextBytes.Length);
			memoryStream.Close ();
			cryptoStream.Close ();
			string plainText = Encoding.UTF8.GetString (plainTextBytes,
													   0,
													   decryptedByteCount);
			return plainText;
		}
public static string StaticDecrypt ( string cipherText , string passPhrase , string saltValue , string hashAlgorithm , int passwordIterations , string initVector , int keySize ) { byte [ ] initVectorBytes = Encoding . ASCII . GetBytes ( initVector ) ; byte [ ] saltValueBytes = Encoding . ASCII . GetBytes ( saltValue ) ; byte [ ] cipherTextBytes = Convert . FromBase64String ( cipherText ) ; PasswordDeriveBytes password = new PasswordDeriveBytes ( passPhrase , saltValueBytes , hashAlgorithm , passwordIterations ) ; byte [ ] keyBytes = password . GetBytes ( keySize / 8 ) ; RijndaelManaged symmetricKey = new RijndaelManaged ( ) ; symmetricKey . Mode = CipherMode . CBC ; ICryptoTransform decryptor = symmetricKey . CreateDecryptor ( keyBytes , initVectorBytes ) ; MemoryStream memoryStream = new MemoryStream ( cipherTextBytes ) ; CryptoStream cryptoStream = new CryptoStream ( memoryStream , decryptor , CryptoStreamMode . Read ) ; byte [ ] plainTextBytes = new byte [ cipherTextBytes . Length ] ; int decryptedByteCount = cryptoStream . Read ( plainTextBytes , 0 , plainTextBytes . Length ) ; memoryStream . Close ( ) ; cryptoStream . Close ( ) ; string plainText = Encoding . UTF8 . GetString ( plainTextBytes , 0 , decryptedByteCount ) ; return plainText ; }
Decrypts specified ciphertext using Rijndael symmetric key algorithm.
Decrypts specified ciphertext using Rijndael symmetric key algorithm .
// 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. // Convert our ciphertext into a byte array. // 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. // Use the password to generate pseudo-random bytes for the encryption // key. Specify the size of the key in bytes (instead of bits). // Create uninitialized Rijndael encryption object. // It is reasonable to set encryption mode to Cipher Block Chaining // (CBC). Use default options for other symmetric key parameters. // Generate decryptor from the existing key bytes and initialization  // vector. Key size will be defined based on the number of the key  // bytes. // Define memory stream which will be used to hold encrypted data. // Define cryptographic stream (always use Read mode for encryption). // 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. // Start decrypting. // Close both streams. // Convert decrypted data into a string.  // Let us assume that the original plaintext string was UTF8-encoded. // Return decrypted string.   
Decrypted string value.
Decrypted string value .
cipherText
string
Base64-formatted ciphertext value.
Base64 - formatted ciphertext value .
passPhrase
string
Passphrase from which a pseudo-random password will be derived. The
derived password will be used to generate the encryption key.
Passphrase can be any string. In this example we assume that this
passphrase is an ASCII string.
Passphrase from which a pseudo - random password will be derived . The derived password will be used to generate the encryption key . Passphrase can be any string . In this example we assume that this passphrase is an ASCII string .
saltValue
string
Salt value used along with passphrase to generate password. Salt can
be any string. In this example we assume that salt is an ASCII string.
Salt value used along with passphrase to generate password . Salt can be any string . In this example we assume that salt is an ASCII string .
hashAlgorithm
string
Hash algorithm used to generate password. Allowed values are: "MD5" and
"SHA1". SHA1 hashes are a bit slower, but more secure than MD5 hashes.
Hash algorithm used to generate password . Allowed values are : " MD5 " and " SHA1 " . SHA1 hashes are a bit slower but more secure than MD5 hashes .
passwordIterations
int
Number of iterations used to generate password. One or two iterations
should be enough.
Number of iterations used to generate password . One or two iterations should be enough .
initVector
string
Initialization vector (or IV). This value is required to encrypt the
first block of plaintext data. For RijndaelManaged class IV must be
exactly 16 ASCII characters long.
Initialization vector ( or IV ) . This value is required to encrypt the first block of plaintext data . For RijndaelManaged class IV must be exactly 16 ASCII characters long .
keySize
int
Size of encryption key in bits.
Size of encryption key in bits .
remarks
Most of the logic in this function is similar to the Encrypt
logic. In order for decryption to work, all parameters of this function
except cipherText value - must match the corresponding parameters of
the Encrypt function which was called to generate the
ciphertext.
Most of the logic in this function is similar to the Encrypt logic . In order for decryption to work all parameters of this function except cipherText value - must match the corresponding parameters of the Encrypt function which was called to generate the ciphertext .