Function encrypt_string_gcm

libcppcryptfs/crypt/crypt.cpp:335–374

}

bool encrypt_string_gcm(const wstring& str, const BYTE *key, string& base64_out)
{
	BYTE iv[BLOCK_IV_LEN];

	bool rval = true;	

	if (!get_sys_random_bytes(iv, sizeof(iv)))
		return false;

	auto context = get_crypt_context(BLOCK_IV_LEN, AES_MODE_GCM);

	if (!context)
		return false;

	try {
		string utf8;
		if (!unicode_to_utf8(&str[0], utf8))
			throw(-1);

		BYTE aad[8];
		memset(aad, 0, sizeof(aad));

		vector<BYTE> encrypted(utf8.size() + BLOCK_IV_LEN + BLOCK_TAG_LEN);

		memcpy(&encrypted[0], iv, sizeof(iv));

		int ctlen = encrypt((const BYTE*)&utf8[0], (int)utf8.size(), aad, (int)sizeof(aad), key, iv, &encrypted[0] + (int)sizeof(iv), &encrypted[0] + sizeof(iv) + utf8.size(), context.get());

		if (ctlen != utf8.size())
			throw(-1);

		if (!base64_encode(&encrypted[0], ctlen + sizeof(iv) + BLOCK_TAG_LEN, base64_out, false, true))
			throw(-1);

	} catch (...) {
		rval = false;
	}	

	return rval;
}

bool decrypt_string_gcm(const string& base64_in, const BYTE *key, wstring& str)
{