C++ Programming assignment

#ifndef CRYPTO_HPP #define CRYPTO_HPP #include <functional> #include <memory> /** * @enum Algorithm * * The purpose of this enumeration is to inform the * static factory method which crypto transform should be * used for when creating a crypto object. */ enum class Algorithm { eNONE, eCAESAR, eAES, eRSA, }; /** * @class Crypto * * The purpose of this class is to serve as an abstract base class for many * cryptologic transforms. */ class Crypto { public: /** * @brief Constructor * * This function creates/initializes this oject. * The callbacks are used by the underlying * algorithm to pass back processed data to the using logic. * * NOTE: There is no correlation between the amount of data passed into the algorithm * and the amount returned from it. Likewise, there is no required correlation between * the number of times data is passed into the algorithm and the number of times callbacks * are called. * * @param encryptCallback Callback function for returning encrypted data * @param decryptCallback Callback function for returning decrypted data */ Crypto(std::function<void(const uint8_t *data, uint32_t len)> encryptCallback, std::function<void(const uint8_t *data, uint32_t len)> decryptCallback); /** * @brief Generate new crypto keys * * This function must be implemented by all derived classes. * It signals the underlying algorithm that it should generate * and store keys needed for that algorithm. */ virtual void genKeys() = 0; /** * @brief Get the keys and return them in a standardized form * * This function must be implemented by all derived classes. * It will allocate memory, and then populate that memory with * keys in a way that can be generically stored/passed by using * programs. * * @param pubKey Pointer to array of bytes containing public key * @param pubLen Lenght of the public key * @param priKey Pointer to array of bytes containing private key * @param priLen Lenght of the private key * @return Indication of valid keys present in response */ virtual bool getKeys(uint8_t **pubKey, uint32_t &pubLen, uint8_t **priKey, uint32_t &priLen) = 0; /** * @brief Set the keys to be used in underlying transform * * This function must be implemented by all derived classes. * It will pass a representation of needed keys to derived * algorithms. * * @param pubKey Pointer to bytes containing public key * @param pubLen Lenght of the public key * @param priKey Pointer to bytes containing private key * @param priLen Lenght of the private key */ virtual void setKeys(const uint8_t *pubKey, uint32_t pubLen, const uint8_t *priKey, uint32_t priLen) = 0; /** * @brief Destroy keys and free resources * * This function must be implemented by all derived classes. * It will inform the derived algorithm that it should "forget" * any created keys and free resources associated with them. * If keys are not present, it should have no action. */ virtual void destroyKeys() = 0; /** * @brief Encrypt raw data buffer (PT to CT) * * This function will pass a data buffer for encyrption * to the underlying algorithm. There should be no restrictions * on the lenght of data that is passed to the algorithm. * * @param data Buffer of data to be encrypted * @param len Length of data buffer * @return bool Success or failure (transform accepted data) */ virtual bool encrypt(const uint8_t *data, uint32_t len) = 0; /** * @brief Decrypt raw data buffer (CT to PT) * * This function will pass a data buffer for decyrption * to the underlying algorithm. There should be no restrictions * on the lenght of data that is passed to the algorithm. * * @param data Buffer of data to be decrypted * @param len Length of data buffer * @return bool Success or failure (transform accepted data) */ virtual bool decrypt(const uint8_t *data, uint32_t len) = 0; /** * @brief Create a Crypto object using the correct transform * * @param encryptCallback Callback function for returning encrypted data * @param decryptCallback Callback function for returning decrypted data * @param algorithm Enum indicationg which transform should be used * @return shared_ptr to newly constructed heap object */ static std::shared_ptr<Crypto> cryptoFactory(std::function<void(const uint8_t *data, uint32_t len)> encryptCallback, std::function<void(const uint8_t *data, uint32_t len)> decryptCallback, Algorithm algorithm); protected: /** @brief Encrypt callback function */ std::function<void(const uint8_t *data, uint32_t len)> m_encryptCallback; /** @brief Decrypt callback function */ std::function<void(const uint8_t *data, uint32_t len)> m_decryptCallback; }; #endif /* CRYPTO_HPP */