62 lines
2.0 KiB
C++
62 lines
2.0 KiB
C++
#include <cryptopp/cryptopp/gcm.h>
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#include "AES256_GCM.h"
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using CryptoPP::GCM;
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using CryptoPP::AES;
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using CryptoPP::AuthenticatedEncryptionFilter;
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using CryptoPP::AuthenticatedDecryptionFilter;
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using CryptoPP::ArraySource;
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using CryptoPP::ArraySink;
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using CryptoPP::GCM_64K_Tables;
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using CryptoPP::HashVerificationFilter;
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using cpputils::Data;
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using cpputils::FixedSizeData;
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namespace blockstore {
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namespace encrypted {
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constexpr unsigned int AES256_GCM::IV_SIZE;
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Data AES256_GCM::encrypt(const byte *plaintext, unsigned int plaintextSize, const EncryptionKey &encKey) {
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FixedSizeData<IV_SIZE> iv = FixedSizeData<IV_SIZE>::CreateRandom();
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GCM<AES, GCM_64K_Tables>::Encryption encryption;
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encryption.SetKeyWithIV(encKey.data(), encKey.BINARY_LENGTH, iv.data(), IV_SIZE);
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Data ciphertext(ciphertextSize(plaintextSize));
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std::memcpy(ciphertext.data(), iv.data(), IV_SIZE);
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ArraySource(plaintext, plaintextSize, true,
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new AuthenticatedEncryptionFilter(encryption,
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new ArraySink((byte*)ciphertext.data() + IV_SIZE, ciphertext.size() - IV_SIZE),
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false, TAG_SIZE
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)
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);
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return ciphertext;
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}
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boost::optional<Data> AES256_GCM::decrypt(const byte *ciphertext, unsigned int ciphertextSize, const EncryptionKey &encKey) {
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if (ciphertextSize < IV_SIZE + TAG_SIZE) {
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return boost::none;
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}
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const byte *ciphertextIV = ciphertext;
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const byte *ciphertextData = ciphertext + IV_SIZE;
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GCM<AES, GCM_64K_Tables>::Decryption decryption;
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decryption.SetKeyWithIV((byte*)encKey.data(), encKey.BINARY_LENGTH, ciphertextIV, IV_SIZE);
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Data plaintext(plaintextSize(ciphertextSize));
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try {
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ArraySource((byte*)ciphertextData, ciphertextSize - IV_SIZE, true,
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new AuthenticatedDecryptionFilter(decryption,
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new ArraySink((byte*)plaintext.data(), plaintext.size()),
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AuthenticatedDecryptionFilter::DEFAULT_FLAGS, TAG_SIZE
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)
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);
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return std::move(plaintext);
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} catch (const HashVerificationFilter::HashVerificationFailed &e) {
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return boost::none;
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}
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}
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}
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}
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