/* * Symmetric Algorithm Base Class * (C) 1999-2007 Jack Lloyd * * Distributed under the terms of the Botan license */ #ifndef BOTAN_SYMMETRIC_ALGORITHM_H__ #define BOTAN_SYMMETRIC_ALGORITHM_H__ #include #include #include #include #include namespace Botan { /** * This class represents a symmetric algorithm object. */ class BOTAN_DLL SymmetricAlgorithm : public Algorithm { public: /** * @return object describing limits on key size */ virtual Key_Length_Specification key_spec() const = 0; /** * @return minimum allowed key length */ size_t maximum_keylength() const { return key_spec().maximum_keylength(); } /** * @return maxmium allowed key length */ size_t minimum_keylength() const { return key_spec().minimum_keylength(); } /** * Check whether a given key length is valid for this algorithm. * @param length the key length to be checked. * @return true if the key length is valid. */ bool valid_keylength(size_t length) const { return key_spec().valid_keylength(length); } /** * Set the symmetric key of this object. * @param key the SymmetricKey to be set. */ void set_key(const SymmetricKey& key) { set_key(key.begin(), key.length()); } /** * Set the symmetric key of this object. * @param key the to be set as a byte array. * @param length in bytes of key param */ void set_key(const byte key[], size_t length) { if(!valid_keylength(length)) throw Invalid_Key_Length(name(), length); key_schedule(key, length); } private: /** * Run the key schedule * @param key the key * @param length of key */ virtual void key_schedule(const byte key[], size_t length) = 0; }; /** * The two possible directions for cipher filters, determining whether they * actually perform encryption or decryption. */ enum Cipher_Dir { ENCRYPTION, DECRYPTION }; } #endif