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Diffstat (limited to 'src/lib/pubkey/mce/polyn_gf2m.h')
-rw-r--r-- | src/lib/pubkey/mce/polyn_gf2m.h | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/lib/pubkey/mce/polyn_gf2m.h b/src/lib/pubkey/mce/polyn_gf2m.h new file mode 100644 index 000000000..9dff549e0 --- /dev/null +++ b/src/lib/pubkey/mce/polyn_gf2m.h @@ -0,0 +1,161 @@ +/** + * (C) Copyright Projet SECRET, INRIA, Rocquencourt + * (C) Bhaskar Biswas and Nicolas Sendrier + * + * (C) 2014 cryptosource GmbH + * (C) 2014 Falko Strenzke [email protected] + * + * Distributed under the terms of the Botan license + * + */ + +#ifndef BOTAN_POLYN_GF2M_H__ +#define BOTAN_POLYN_GF2M_H__ + +#include <botan/gf2m_small_m.h> +#include <botan/rng.h> +#include <memory> +#include <utility> + +namespace Botan { + +using namespace gf2m_small_m; + +struct polyn_gf2m + { + public: + /** + * create a zero polynomial: + */ + polyn_gf2m( std::shared_ptr<gf2m_small_m::Gf2m_Field> sp_field ); + + polyn_gf2m() + :m_deg(-1) + {}; + + polyn_gf2m(const secure_vector<byte>& encoded, std::shared_ptr<gf2m_small_m::Gf2m_Field> sp_field ); + + polyn_gf2m& operator=(const polyn_gf2m&) = default; + + bool operator==(const polyn_gf2m & other) const ; + + bool operator!=(const polyn_gf2m & other) const { return !(*this == other); }; + + polyn_gf2m(polyn_gf2m&& other) + { + this->swap(other); + }; + + polyn_gf2m & operator=(polyn_gf2m&& other) + { + if(this != &other) + { + this->swap(other); + } + return *this; + } + + void swap(polyn_gf2m& other); + + secure_vector<byte> encode() const; + /** + * create zero polynomial with reservation of space for a degree d polynomial + */ + polyn_gf2m(int d, std::shared_ptr<gf2m_small_m::Gf2m_Field> sp_field); + + polyn_gf2m(polyn_gf2m const& other); + /** + * create zero polynomial with allocated size determined by specified degree d: + */ + + /** + * random irreducible polynomial of degree t + */ + polyn_gf2m(int t, RandomNumberGenerator& rng, std::shared_ptr<gf2m_small_m::Gf2m_Field> sp_field); + + std::shared_ptr<gf2m_small_m::Gf2m_Field> get_sp_field() const + { return msp_field; }; + + gf2m& operator[](size_t i) { return coeff[i]; }; + + gf2m operator[](size_t i) const { return coeff[i]; } + + gf2m get_lead_coef() const { return coeff[m_deg]; } + + gf2m get_coef(u32bit i) const { return coeff[i]; } + + inline void set_coef(u32bit i, gf2m v) + { + coeff[i] = v; + }; + + inline void add_to_coef(u32bit i, gf2m v) + { + coeff[i] = coeff[i] ^ v; + } + + std::string to_string() const; + + /** decode a polynomial from memory: **/ + polyn_gf2m(const byte* mem, u32bit mem_len, std::shared_ptr<gf2m_small_m::Gf2m_Field> sp_field); + // remove one! ^v! + /** + * create a polynomial from memory area (encoded) + */ + polyn_gf2m(int degree, const unsigned char* mem, u32bit mem_byte_len, std::shared_ptr<gf2m_small_m::Gf2m_Field> sp_field); + + void encode(u32bit min_numo_coeffs, byte* mem, u32bit mem_len) const; + + int get_degree() const; + + /** + * determine the degree in a timing secure manner. the timing of this function + * only depends on the number of allocated coefficients, not on the actual + * degree + */ + int calc_degree_secure() const; + + void degppf(const polyn_gf2m & g, int* p_result); + + static std::vector<polyn_gf2m> sqmod_init(const polyn_gf2m & g); + + static std::vector<polyn_gf2m> sqrt_mod_init(const polyn_gf2m & g); + + + polyn_gf2m sqmod(const std::vector<polyn_gf2m> & sq, int d); + void set_to_zero(); + gf2m eval(gf2m a); + + static std::pair<polyn_gf2m, polyn_gf2m> eea_with_coefficients(const polyn_gf2m & p, + const polyn_gf2m & g, + int break_deg); + + void patchup_deg_secure( u32bit trgt_deg, volatile gf2m patch_elem); + + private: + + void set_degree(int d) { m_deg = d; } + + void poly_shiftmod( const polyn_gf2m & g); + void realloc(u32bit new_size); + static polyn_gf2m gcd(polyn_gf2m const& p1, polyn_gf2m const& p2); + + /** + * destructive: + */ + static void remainder(polyn_gf2m & p, const polyn_gf2m & g); + + static polyn_gf2m gcd_aux(polyn_gf2m& p1, polyn_gf2m& p2); + public: + int m_deg; + secure_vector<gf2m> coeff; + std::shared_ptr<gf2m_small_m::Gf2m_Field> msp_field; + }; + +gf2m random_code_element(unsigned code_length, RandomNumberGenerator& rng); + +std::vector<polyn_gf2m> syndrome_init(polyn_gf2m const& generator, std::vector<gf2m> const& support, int n); + +} + +#endif |