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/*
* (C) 2013 Jack Lloyd
* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_GCM_GHASH_H_
#define BOTAN_GCM_GHASH_H_
#include <botan/sym_algo.h>
namespace Botan {
/**
* GCM's GHASH
* This is not intended for general use, but is exposed to allow
* shared code between GCM and GMAC
*/
class BOTAN_PUBLIC_API(2,0) GHASH final : public SymmetricAlgorithm
{
public:
void set_associated_data(const uint8_t ad[], size_t ad_len);
secure_vector<uint8_t> nonce_hash(const uint8_t nonce[], size_t len);
void start(const uint8_t nonce[], size_t len);
/*
* Assumes input len is multiple of 16
*/
void update(const uint8_t in[], size_t len);
/*
* Incremental update of associated data
*/
void update_associated_data(const uint8_t ad[], size_t len);
secure_vector<uint8_t> final();
Key_Length_Specification key_spec() const override
{ return Key_Length_Specification(16); }
void clear() override;
void reset();
std::string name() const override { return "GHASH"; }
std::string provider() const;
void ghash_update(secure_vector<uint8_t>& x,
const uint8_t input[], size_t input_len);
void add_final_block(secure_vector<uint8_t>& x,
size_t ad_len, size_t pt_len);
private:
void key_schedule(const uint8_t key[], size_t key_len) override;
void gcm_multiply(secure_vector<uint8_t>& x,
const uint8_t input[],
size_t blocks);
static const size_t GCM_BS = 16;
secure_vector<uint8_t> m_H;
secure_vector<uint8_t> m_H_ad;
secure_vector<uint8_t> m_ghash;
secure_vector<uint8_t> m_nonce;
secure_vector<uint64_t> m_HM;
secure_vector<uint64_t> m_H_pow;
size_t m_ad_len = 0;
size_t m_text_len = 0;
};
}
#endif
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