| public CreateEncryptor ( ) : ICryptoTransform | ||
| return | ICryptoTransform | |
/// <summary>
/// Constructor.
/// </summary>
/// <param name="key">Password string</param>
/// <param name="saltBytes">Random bytes, length depends on encryption strength.
/// 128 bits = 8 bytes, 192 bits = 12 bytes, 256 bits = 16 bytes.</param>
/// <param name="blockSize">The encryption strength, in bytes eg 16 for 128 bits.</param>
/// <param name="writeMode">True when creating a zip, false when reading. For the AuthCode.</param>
///
public ZipAESTransform(string key, byte[] saltBytes, int blockSize, bool writeMode)
{
if (blockSize != 16 && blockSize != 32) // 24 valid for AES but not supported by Winzip
{
throw new Exception("Invalid blocksize " + blockSize + ". Must be 16 or 32.");
}
if (saltBytes.Length != blockSize / 2)
{
throw new Exception("Invalid salt len. Must be " + blockSize / 2 + " for blocksize " + blockSize);
}
// initialise the encryption buffer and buffer pos
_blockSize = blockSize;
_encryptBuffer = new byte[_blockSize];
_encrPos = ENCRYPT_BLOCK;
// Performs the equivalent of derive_key in Dr Brian Gladman's pwd2key.c
var pdb = new Rfc2898DeriveBytes(key, saltBytes, KEY_ROUNDS);
var rm = new RijndaelImplementation();
rm.Mode = CipherMode.ECB; // No feedback from cipher for CTR mode
_counterNonce = new byte[_blockSize];
byte[] byteKey1 = pdb.GetBytes(_blockSize);
byte[] byteKey2 = pdb.GetBytes(_blockSize);
_encryptor = rm.CreateEncryptor(byteKey1, byteKey2);
_pwdVerifier = pdb.GetBytes(PWD_VER_LENGTH);
//
#if !OS_WINDOWS
incrementalHash = IncrementalHash.CreateHMAC(HashAlgorithmName.SHA1, byteKey2);
#else
_hmacsha1 = new HMACSHA1(byteKey2);
#endif
_writeMode = writeMode;
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="key">Password string</param>
/// <param name="saltBytes">Random bytes, length depends on encryption strength.
/// 128 bits = 8 bytes, 192 bits = 12 bytes, 256 bits = 16 bytes.</param>
/// <param name="blockSize">The encryption strength, in bytes eg 16 for 128 bits.</param>
/// <param name="writeMode">True when creating a zip, false when reading. For the AuthCode.</param>
///
public ZipAESTransform(string key, byte[] saltBytes, int blockSize, bool writeMode) {
if (blockSize!=16&&blockSize!=32) // 24 valid for AES but not supported by Winzip
throw new Exception("Invalid blocksize "+blockSize+". Must be 16 or 32.");
if (saltBytes.Length!=blockSize/2)
throw new Exception("Invalid salt len. Must be "+blockSize/2+" for blocksize "+blockSize);
// initialise the encryption buffer and buffer pos
_blockSize=blockSize;
_encryptBuffer=new byte[_blockSize];
_encrPos=ENCRYPT_BLOCK;
// Performs the equivalent of derive_key in Dr Brian Gladman's pwd2key.c
var pdb=new Rfc2898DeriveBytes(key, saltBytes, KEY_ROUNDS);
var rm=new RijndaelImplementation();
rm.Mode=CipherMode.ECB; // No feedback from cipher for CTR mode
_counterNonce=new byte[_blockSize];
byte[] byteKey1=pdb.GetBytes(_blockSize);
byte[] byteKey2=pdb.GetBytes(_blockSize);
_encryptor=rm.CreateEncryptor(byteKey1, byteKey2);
_pwdVerifier=pdb.GetBytes(PWD_VER_LENGTH);
//
#if !OS_WINDOWS
incrementalHash = IncrementalHash.CreateHMAC(HashAlgorithmName.SHA1, byteKey2);
#else
_hmacsha1=new HMACSHA1(byteKey2);
#endif
_writeMode=writeMode;
}
