bool VolumeHeader::Decrypt (const ConstBufferPtr &encryptedData, const VolumePassword &password, const Pkcs5KdfList &keyDerivationFunctions, const EncryptionAlgorithmList &encryptionAlgorithms, const EncryptionModeList &encryptionModes)
{
if (password.Size() < 1)
throw PasswordEmpty (SRC_POS);
ConstBufferPtr salt (encryptedData.GetRange (SaltOffset, SaltSize));
SecureBuffer header (EncryptedHeaderDataSize);
SecureBuffer headerKey (GetLargestSerializedKeySize());
foreach (shared_ptr <Pkcs5Kdf> pkcs5, keyDerivationFunctions)
{
pkcs5->DeriveKey (headerKey, password, salt);
foreach (shared_ptr <EncryptionMode> mode, encryptionModes)
{
if (typeid (*mode) != typeid (EncryptionModeXTS))
mode->SetKey (headerKey.GetRange (0, mode->GetKeySize()));
foreach (shared_ptr <EncryptionAlgorithm> ea, encryptionAlgorithms)
{
if (!ea->IsModeSupported (mode))
continue;
/*
printf("trying %ls, %ls, %ls\n", pkcs5->GetName().c_str(),
mode->GetName().c_str(),
ea->GetName().c_str()
);
*/
if (typeid (*mode) == typeid (EncryptionModeXTS))
{
ea->SetKey (headerKey.GetRange (0, ea->GetKeySize()));
mode = mode->GetNew();
mode->SetKey (headerKey.GetRange (ea->GetKeySize(), ea->GetKeySize()));
}
else
{
ea->SetKey (headerKey.GetRange (LegacyEncryptionModeKeyAreaSize, ea->GetKeySize()));
}
ea->SetMode (mode);
header.CopyFrom (encryptedData.GetRange (EncryptedHeaderDataOffset, EncryptedHeaderDataSize));
ea->Decrypt (header);
if (Deserialize (header, ea, mode))
{
EA = ea;
Pkcs5 = pkcs5;
return true;
}
}
}
}
void VolumePassword::Set (const VolumePassword &password)
{
Set (password.DataPtr(), password.Size());
}