/**
* Initialize the builder from scratch
*/
public void Initialize(EncryptionInfo info, CipherAlgorithm cipherAlgorithm, HashAlgorithm hashAlgorithm, int keyBits, int blockSize, ChainingMode chainingMode)
{
this.info = info;
if (cipherAlgorithm == null)
{
cipherAlgorithm = CipherAlgorithm.aes128;
}
if (cipherAlgorithm != CipherAlgorithm.aes128 &&
cipherAlgorithm != CipherAlgorithm.aes192 &&
cipherAlgorithm != CipherAlgorithm.aes256)
{
throw new EncryptedDocumentException("Standard encryption only supports AES128/192/256.");
}
if (hashAlgorithm == null)
{
hashAlgorithm = HashAlgorithm.sha1;
}
if (hashAlgorithm != HashAlgorithm.sha1)
{
throw new EncryptedDocumentException("Standard encryption only supports SHA-1.");
}
if (chainingMode == null)
{
chainingMode = ChainingMode.ecb;
}
if (chainingMode != ChainingMode.ecb)
{
throw new EncryptedDocumentException("Standard encryption only supports ECB chaining.");
}
if (keyBits == -1)
{
keyBits = cipherAlgorithm.defaultKeySize;
}
if (blockSize == -1)
{
blockSize = cipherAlgorithm.blockSize;
}
bool found = false;
foreach (int ks in cipherAlgorithm.allowedKeySize)
{
found |= (ks == keyBits);
}
if (!found)
{
throw new EncryptedDocumentException("KeySize " + keyBits + " not allowed for Cipher " + cipherAlgorithm.ToString());
}
header = new StandardEncryptionHeader(cipherAlgorithm, hashAlgorithm, keyBits, blockSize, chainingMode);
verifier = new StandardEncryptionVerifier(cipherAlgorithm, hashAlgorithm, keyBits, blockSize, chainingMode);
decryptor = new StandardDecryptor(this);
encryptor = new StandardEncryptor(this);
}
FileStream rawStream;// maybe has memory leak problem.
protected internal StandardCipherOutputStream(DirectoryNode dir, StandardEncryptor encryptor)
{
this.encryptor = encryptor;
this.dir = dir;
fileOut = TempFile.CreateTempFile("encrypted_package", "crypt");
rawStream = new FileStream(fileOut.FullName, FileMode.Open, FileAccess.ReadWrite); // fileOut.Create();
// although not documented, we need the same padding as with agile encryption
// and instead of calculating the missing bytes for the block size ourselves
// we leave it up to the CipherOutputStream, which generates/saves them on close()
// ... we can't use "NoPAdding" here
//
// see also [MS-OFFCRYPT] - 2.3.4.15
// The data block MUST be padded to the next integral multiple of the
// KeyData.blockSize value. Any pAdding bytes can be used. Note that the StreamSize
// field of the EncryptedPackage field specifies the number of bytes of
// unencrypted data as specified in section 2.3.4.4.
CipherOutputStream cryptStream = new CipherOutputStream(rawStream,
encryptor.GetCipher(encryptor.GetSecretKey(), "PKCS5Padding"));
this.out1 = cryptStream;
}
