/* * CFB mode * (C) 1999-2007,2013 Jack Lloyd * * Botan is released under the Simplified BSD License (see license.txt) */ #ifndef BOTAN_MODE_CFB_H__ #define BOTAN_MODE_CFB_H__ #include #include #include namespace Botan { /** * CFB Mode */ class BOTAN_DLL CFB_Mode : public Cipher_Mode { public: std::string name() const override; size_t update_granularity() const override; size_t minimum_final_size() const override; Key_Length_Specification key_spec() const override; size_t output_length(size_t input_length) const override; size_t default_nonce_length() const override; bool valid_nonce_length(size_t n) const override; void clear() override; protected: CFB_Mode(BlockCipher* cipher, size_t feedback_bits); const BlockCipher& cipher() const { return *m_cipher; } size_t feedback() const { return m_feedback_bytes; } secure_vector& shift_register() { return m_shift_register; } secure_vector& keystream_buf() { return m_keystream_buf; } private: secure_vector start_raw(const byte nonce[], size_t nonce_len) override; void key_schedule(const byte key[], size_t length) override; std::unique_ptr m_cipher; secure_vector m_shift_register; secure_vector m_keystream_buf; size_t m_feedback_bytes; }; /** * CFB Encryption */ class BOTAN_DLL CFB_Encryption : public CFB_Mode { public: CFB_Encryption(BlockCipher* cipher, size_t feedback_bits) : CFB_Mode(cipher, feedback_bits) {} void update(secure_vector& blocks, size_t offset = 0) override; void finish(secure_vector& final_block, size_t offset = 0) override; }; /** * CFB Decryption */ class BOTAN_DLL CFB_Decryption : public CFB_Mode { public: CFB_Decryption(BlockCipher* cipher, size_t feedback_bits) : CFB_Mode(cipher, feedback_bits) {} void update(secure_vector& blocks, size_t offset = 0) override; void finish(secure_vector& final_block, size_t offset = 0) override; }; } #endif