/* * Symmetric Key Length Specification * (C) 2010 Jack Lloyd * * Distributed under the terms of the Botan license */ #ifndef BOTAN_KEY_LEN_SPECIFICATION_H__ #define BOTAN_KEY_LEN_SPECIFICATION_H__ #include namespace Botan { /** * Represents the length requirements on an algorithm key */ class BOTAN_DLL Key_Length_Specification { public: /** * Constructor for fixed length keys * @param keylen the supported key length */ Key_Length_Specification(size_t keylen) : min_keylen(keylen), max_keylen(keylen), keylen_mod(1) { } /** * Constructor for variable length keys * @param min_k the smallest supported key length * @param max_k the largest supported key length * @param k_mod the number of bytes the key must be a multiple of */ Key_Length_Specification(size_t min_k, size_t max_k, size_t k_mod = 1) : min_keylen(min_k), max_keylen(max_k ? max_k : min_k), keylen_mod(k_mod) { } /** * @param length is a key length in bytes * @return true iff this length is a valid length for this algo */ bool valid_keylength(size_t length) const { return ((length >= min_keylen) && (length <= max_keylen) && (length % keylen_mod == 0)); } /** * @return minimum key length in bytes */ size_t minimum_keylength() const { return min_keylen; } /** * @return maximum key length in bytes */ size_t maximum_keylength() const { return max_keylen; } /** * @return key length multiple in bytes */ size_t keylength_multiple() const { return keylen_mod; } private: size_t min_keylen, max_keylen, keylen_mod; }; } #endif