protected internal static byte[] hashInput(IEncryptionInfoBuilder builder, byte[] pwHash, byte[] blockKey, byte[] inputKey, int cipherMode)
{
EncryptionVerifier ver = builder.GetVerifier();
AgileDecryptor dec = (AgileDecryptor)builder.GetDecryptor();
int keySize = dec.GetKeySizeInBytes();
int blockSize = dec.GetBlockSizeInBytes();
HashAlgorithm hashAlgo = ver.HashAlgorithm;
byte[] salt = ver.Salt;
byte[] intermedKey = CryptoFunctions.GenerateKey(pwHash, hashAlgo, blockKey, keySize);
ISecretKey skey = new SecretKeySpec(intermedKey, ver.CipherAlgorithm.jceId);
byte[] iv = CryptoFunctions.GenerateIv(hashAlgo, salt, null, blockSize);
Cipher cipher = CryptoFunctions.GetCipher(skey, ver.CipherAlgorithm, ver.ChainingMode, iv, cipherMode);
byte[] hashFinal;
try {
inputKey = CryptoFunctions.GetBlock0(inputKey, GetNextBlockSize(inputKey.Length, blockSize));
hashFinal = cipher.DoFinal(inputKey);
return(hashFinal);
} catch (Exception e) {
throw new EncryptedDocumentException(e);
}
}
protected internal static Cipher InitCipherForBlock(Cipher cipher, int block,
IEncryptionInfoBuilder builder, ISecretKey skey, int encryptMode)
{
EncryptionVerifier ver = builder.GetVerifier();
HashAlgorithm hashAlgo = ver.HashAlgorithm;
byte[] blockKey = new byte[4];
LittleEndian.PutUInt(blockKey, 0, block);
byte[] encKey = CryptoFunctions.GenerateKey(skey.GetEncoded(), hashAlgo, blockKey, 16);
ISecretKey key = new SecretKeySpec(encKey, skey.GetAlgorithm());
if (cipher == null)
{
EncryptionHeader em = builder.GetHeader();
cipher = CryptoFunctions.GetCipher(key, em.CipherAlgorithm, null, null, encryptMode);
}
else
{
cipher.Init(encryptMode, key);
}
return(cipher);
}
protected internal static ISecretKey GenerateSecretKey(string password, EncryptionVerifier ver, int keySize)
{
HashAlgorithm hashAlgo = ver.HashAlgorithm;
byte[] pwHash = CryptoFunctions.HashPassword(password, hashAlgo, ver.Salt, ver.SpinCount);
byte[] blockKey = new byte[4];
LittleEndian.PutInt(blockKey, 0, 0);
byte[] finalHash = CryptoFunctions.GenerateKey(pwHash, hashAlgo, blockKey, hashAlgo.hashSize);
byte[] x1 = FillAndXor(finalHash, (byte)0x36);
byte[] x2 = FillAndXor(finalHash, (byte)0x5c);
byte[] x3 = new byte[x1.Length + x2.Length];
Array.Copy(x1, 0, x3, 0, x1.Length);
Array.Copy(x2, 0, x3, x1.Length, x2.Length);
byte[] key = Arrays.CopyOf(x3, keySize);
ISecretKey skey = new SecretKeySpec(key, ver.CipherAlgorithm.jceId);
return(skey);
}
