/* * HMAC * (C) 1999-2007 Jack Lloyd * 2007 Yves Jerschow * * Distributed under the terms of the Botan license */ #include <botan/hmac.h> #include <botan/xor_buf.h> namespace Botan { /* * Update a HMAC Calculation */ void HMAC::add_data(const byte input[], u32bit length) { hash->update(input, length); } /* * Finalize a HMAC Calculation */ void HMAC::final_result(byte mac[]) { hash->final(mac); hash->update(o_key); hash->update(mac, OUTPUT_LENGTH); hash->final(mac); hash->update(i_key); } /* * HMAC Key Schedule */ void HMAC::key_schedule(const byte key[], u32bit length) { hash->clear(); std::fill(i_key.begin(), i_key.end(), 0x36); std::fill(o_key.begin(), o_key.end(), 0x5C); if(length > hash->HASH_BLOCK_SIZE) { SecureVector<byte> hmac_key = hash->process(key, length); xor_buf(i_key, hmac_key, hmac_key.size()); xor_buf(o_key, hmac_key, hmac_key.size()); } else { xor_buf(i_key, key, length); xor_buf(o_key, key, length); } hash->update(i_key); } /* * Clear memory of sensitive data */ void HMAC::clear() { hash->clear(); i_key.clear(); o_key.clear(); } /* * Return the name of this type */ std::string HMAC::name() const { return "HMAC(" + hash->name() + ")"; } /* * Return a clone of this object */ MessageAuthenticationCode* HMAC::clone() const { return new HMAC(hash->clone()); } /* * HMAC Constructor */ HMAC::HMAC(HashFunction* hash_in) : MessageAuthenticationCode(hash_in->OUTPUT_LENGTH, 1, 2*hash_in->HASH_BLOCK_SIZE), hash(hash_in) { if(hash->HASH_BLOCK_SIZE == 0) throw Invalid_Argument("HMAC cannot be used with " + hash->name()); i_key.create(hash->HASH_BLOCK_SIZE); o_key.create(hash->HASH_BLOCK_SIZE); } }