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Added error messages when block decryption fails

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This commit is contained in:
Sebastian Messmer 2015-04-26 16:45:00 +02:00
parent 09bc28e810
commit 5f83c133b0
1 changed files with 4 additions and 0 deletions
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4
implementations/encrypted/EncryptedBlock.h
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@ -72,10 +72,14 @@ std::unique_ptr<EncryptedBlock<Cipher>> EncryptedBlock<Cipher>::TryDecrypt(std::
boost::optional<cpputils::Data> plaintextWithHeader = Cipher::decrypt((byte*)baseBlock->data(), baseBlock->size(), encKey); boost::optional<cpputils::Data> plaintextWithHeader = Cipher::decrypt((byte*)baseBlock->data(), baseBlock->size(), encKey);
if(!plaintextWithHeader) { if(!plaintextWithHeader) {
//Decryption failed (e.g. an authenticated cipher detected modifications to the ciphertext) //Decryption failed (e.g. an authenticated cipher detected modifications to the ciphertext)
//TODO Think about logging
std::cerr << "Decrypting block " << baseBlock->key() << " failed. Was the block modified by an attacker?" << std::endl;
return nullptr; return nullptr;
} }
if(!_keyHeaderIsCorrect(baseBlock->key(), *plaintextWithHeader)) { if(!_keyHeaderIsCorrect(baseBlock->key(), *plaintextWithHeader)) {
//The stored key in the block data is incorrect - an attacker might have exchanged the contents with the encrypted data from a different block //The stored key in the block data is incorrect - an attacker might have exchanged the contents with the encrypted data from a different block
//TODO Think about logging
std::cerr << "Decrypting block " << baseBlock->key() << " failed due to invalid block key. Was the block modified by an attacker?" << std::endl;
return nullptr; return nullptr;
} }
return std::make_unique<EncryptedBlock<Cipher>>(std::move(baseBlock), encKey, std::move(*plaintextWithHeader)); return std::make_unique<EncryptedBlock<Cipher>>(std::move(baseBlock), encKey, std::move(*plaintextWithHeader));