77 lines
2.5 KiB
C++
77 lines
2.5 KiB
C++
#include "EncryptedBlock.h"
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#include <cryptopp/cryptopp/modes.h>
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#include "../../utils/BlockStoreUtils.h"
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using CryptoPP::CFB_Mode;
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using CryptoPP::AES;
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using std::make_unique;
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namespace blockstore {
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namespace encrypted {
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constexpr unsigned int EncryptedBlock::IV_SIZE;
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std::unique_ptr<EncryptedBlock> EncryptedBlock::CreateNew(std::unique_ptr<Block> baseBlock, const EncryptionKey &encKey) {
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auto block = make_unique<EncryptedBlock>(std::move(baseBlock), encKey);
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//We have to explicitly fill the block with zeroes, because otherwise the encrypted version is filled with zeroes and not the plaintext version
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utils::fillWithZeroes(block.get());
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return block;
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}
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EncryptedBlock::EncryptedBlock(std::unique_ptr<Block> baseBlock, const EncryptionKey &encKey)
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:Block(baseBlock->key()),
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_baseBlock(std::move(baseBlock)),
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_plaintextData(USEABLE_BLOCK_SIZE(_baseBlock->size())),
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_encKey(encKey),
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_dataChanged(false) {
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_decryptFromBaseBlock();
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}
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EncryptedBlock::~EncryptedBlock() {
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flush();
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}
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const void *EncryptedBlock::data() const {
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return _plaintextData.data();
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}
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void EncryptedBlock::write(const void *source, uint64_t offset, uint64_t size) {
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assert(offset <= _plaintextData.size() && offset + size <= _plaintextData.size()); //Also check offset < _data->size() because of possible overflow in the addition
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std::memcpy((uint8_t*)_plaintextData.data()+offset, source, size);
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_dataChanged = true;
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}
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void EncryptedBlock::flush() {
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_encryptToBaseBlock();
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return _baseBlock->flush();
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}
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size_t EncryptedBlock::size() const {
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return _plaintextData.size();
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}
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void EncryptedBlock::_decryptFromBaseBlock() {
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const byte *iv = (byte*)_baseBlock->data();
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const byte *data = (byte*)_baseBlock->data() + IV_SIZE;
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auto decryption = CFB_Mode<AES>::Decryption((byte*)_encKey.data(), EncryptionKey::BINARY_LENGTH, iv);
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decryption.ProcessData((byte*)_plaintextData.data(), data, _plaintextData.size());
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}
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void EncryptedBlock::_encryptToBaseBlock() {
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if (_dataChanged) {
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FixedSizeData<IV_SIZE> iv = FixedSizeData<IV_SIZE>::CreateRandom();
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auto encryption = CFB_Mode<AES>::Encryption(_encKey.data(), EncryptionKey::BINARY_LENGTH, iv.data());
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//TODO More performance when not using "Data encrypted" object, but specialized CryptoPP sink
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Data encrypted(_plaintextData.size());
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encryption.ProcessData((byte*)encrypted.data(), (byte*)_plaintextData.data(), _plaintextData.size());
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_baseBlock->write(iv.data(), 0, IV_SIZE);
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_baseBlock->write(encrypted.data(), IV_SIZE, encrypted.size());
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_dataChanged = false;
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}
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}
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}
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}
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