Botan  2.15.0
Crypto and TLS for C++11
polyn_gf2m.h
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1 /*
2  * (C) Copyright Projet SECRET, INRIA, Rocquencourt
3  * (C) Bhaskar Biswas and Nicolas Sendrier
4  *
5  * (C) 2014 cryptosource GmbH
6  * (C) 2014 Falko Strenzke fstrenzke@cryptosource.de
7  *
8  * Botan is released under the Simplified BSD License (see license.txt)
9  *
10  */
11 
12 #ifndef BOTAN_POLYN_GF2M_H_
13 #define BOTAN_POLYN_GF2M_H_
14 
15 #include <botan/secmem.h>
16 #include <botan/gf2m_small_m.h>
17 #include <utility>
18 #include <string>
19 
20 //BOTAN_FUTURE_INTERNAL_HEADER(polyn_gf2m.h)
21 
22 namespace Botan {
23 
24 class RandomNumberGenerator;
25 
27  {
28  public:
29  /**
30  * create a zero polynomial:
31  */
32  explicit polyn_gf2m(std::shared_ptr<GF2m_Field> sp_field);
33 
34  polyn_gf2m() : m_deg(-1) {}
35 
36  polyn_gf2m(const secure_vector<uint8_t>& encoded, std::shared_ptr<GF2m_Field> sp_field);
37 
38  polyn_gf2m& operator=(const polyn_gf2m&) = default;
39 
40  /**
41  * create zero polynomial with reservation of space for a degree d polynomial
42  */
43  polyn_gf2m(int d, std::shared_ptr<GF2m_Field> sp_field);
44 
45  polyn_gf2m(polyn_gf2m const& other);
46 
47  /**
48  * random irreducible polynomial of degree t
49  */
50  polyn_gf2m(size_t t, RandomNumberGenerator& rng, std::shared_ptr<GF2m_Field> sp_field);
51 
52  /** decode a polynomial from memory: **/
53  polyn_gf2m(const uint8_t* mem, uint32_t mem_len, std::shared_ptr<GF2m_Field> sp_field);
54 
55  /**
56  * create a polynomial from memory area (encoded)
57  */
58  polyn_gf2m(int degree, const uint8_t* mem, size_t mem_byte_len, std::shared_ptr<GF2m_Field> sp_field);
59 
60  bool operator==(const polyn_gf2m & other) const ;
61 
62  bool operator!=(const polyn_gf2m & other) const { return !(*this == other); }
63 
65  {
66  this->swap(other);
67  }
68 
70  {
71  if(this != &other)
72  {
73  this->swap(other);
74  }
75  return *this;
76  }
77 
78  void swap(polyn_gf2m& other);
79 
81 
82  std::shared_ptr<GF2m_Field> get_sp_field() const
83  { return m_sp_field; }
84 
85  gf2m& operator[](size_t i) { return coeff[i]; }
86 
87  gf2m operator[](size_t i) const { return coeff[i]; }
88 
89  gf2m get_lead_coef() const { return coeff[m_deg]; }
90 
91  gf2m get_coef(size_t i) const { return coeff[i]; }
92 
93  inline void set_coef(size_t i, gf2m v)
94  {
95  coeff[i] = v;
96  }
97 
98  inline void add_to_coef(size_t i, gf2m v)
99  {
100  coeff[i] ^= v;
101  }
102 
103  std::string to_string() const;
104 
105  void encode(uint32_t min_numo_coeffs, uint8_t* mem, uint32_t mem_len) const;
106 
107  int get_degree() const;
108 
109  /**
110  * determine the degree in a timing secure manner. the timing of this function
111  * only depends on the number of allocated coefficients, not on the actual
112  * degree
113  */
114  int calc_degree_secure() const;
115 
116  size_t degppf(const polyn_gf2m& g);
117 
118  static std::vector<polyn_gf2m> sqmod_init(const polyn_gf2m & g);
119 
120  static std::vector<polyn_gf2m> sqrt_mod_init(const polyn_gf2m & g);
121 
122 
123  polyn_gf2m sqmod(const std::vector<polyn_gf2m> & sq, int d);
124  void set_to_zero();
125  gf2m eval(gf2m a);
126 
127  static std::pair<polyn_gf2m, polyn_gf2m> eea_with_coefficients(const polyn_gf2m & p,
128  const polyn_gf2m & g,
129  int break_deg);
130 
131  void patchup_deg_secure( uint32_t trgt_deg, volatile gf2m patch_elem);
132 
133  private:
134 
135  void set_degree(int d) { m_deg = d; }
136 
137  void poly_shiftmod( const polyn_gf2m & g);
138  void realloc(uint32_t new_size);
139  static polyn_gf2m gcd(polyn_gf2m const& p1, polyn_gf2m const& p2);
140 
141  /**
142  * destructive:
143  */
144  static void remainder(polyn_gf2m & p, const polyn_gf2m & g);
145 
146  static polyn_gf2m gcd_aux(polyn_gf2m& p1, polyn_gf2m& p2);
147  public:
148  // public member variable:
149  int m_deg;
150 
151  // public member variable:
153 
154  // public member variable:
155  std::shared_ptr<GF2m_Field> m_sp_field;
156  };
157 
159 gf2m random_code_element(uint16_t code_length, RandomNumberGenerator& rng);
160 
161 std::vector<polyn_gf2m> syndrome_init(polyn_gf2m const& generator, std::vector<gf2m> const& support, int n);
162 
163 /**
164 * Find the roots of a polynomial over GF(2^m) using the method by Federenko et al.
165 */
166 secure_vector<gf2m> find_roots_gf2m_decomp(const polyn_gf2m & polyn, size_t code_length);
167 
168 }
169 
170 #endif
int get_degree() const
Definition: polyn_gf2m.cpp:228
size_t degppf(const polyn_gf2m &g)
Definition: polyn_gf2m.cpp:390
int calc_degree_secure() const
Definition: polyn_gf2m.cpp:46
gf2m get_lead_coef() const
Definition: polyn_gf2m.h:89
gf2m & operator[](size_t i)
Definition: polyn_gf2m.h:85
bool operator==(const polyn_gf2m &other) const
Definition: polyn_gf2m.cpp:797
gf2m get_coef(size_t i) const
Definition: polyn_gf2m.h:91
polyn_gf2m sqmod(const std::vector< polyn_gf2m > &sq, int d)
Definition: polyn_gf2m.cpp:323
static std::vector< polyn_gf2m > sqrt_mod_init(const polyn_gf2m &g)
Definition: polyn_gf2m.cpp:676
polyn_gf2m & operator=(polyn_gf2m &&other)
Definition: polyn_gf2m.h:69
void patchup_deg_secure(uint32_t trgt_deg, volatile gf2m patch_elem)
Definition: polyn_gf2m.cpp:429
uint16_t gf2m
Definition: gf2m_small_m.h:23
Definition: alg_id.cpp:13
polyn_gf2m(polyn_gf2m &&other)
Definition: polyn_gf2m.h:64
bool operator!=(const polyn_gf2m &other) const
Definition: polyn_gf2m.h:62
static std::vector< polyn_gf2m > sqmod_init(const polyn_gf2m &g)
Definition: polyn_gf2m.cpp:289
secure_vector< gf2m > coeff
Definition: polyn_gf2m.h:152
void add_to_coef(size_t i, gf2m v)
Definition: polyn_gf2m.h:98
gf2m operator[](size_t i) const
Definition: polyn_gf2m.h:87
gf2m random_code_element(uint16_t code_length, RandomNumberGenerator &rng)
Definition: polyn_gf2m.cpp:71
std::vector< polyn_gf2m > syndrome_init(polyn_gf2m const &generator, std::vector< gf2m > const &support, int n)
Definition: polyn_gf2m.cpp:721
static std::pair< polyn_gf2m, polyn_gf2m > eea_with_coefficients(const polyn_gf2m &p, const polyn_gf2m &g, int break_deg)
Definition: polyn_gf2m.cpp:448
polyn_gf2m & operator=(const polyn_gf2m &)=default
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65
std::shared_ptr< GF2m_Field > get_sp_field() const
Definition: polyn_gf2m.h:82
secure_vector< gf2m > find_roots_gf2m_decomp(const polyn_gf2m &polyn, size_t code_length)
secure_vector< uint8_t > encode() const
Definition: polyn_gf2m.cpp:769
gf2m random_gf2m(RandomNumberGenerator &rng)
Definition: polyn_gf2m.cpp:64
std::string to_string() const
Definition: polyn_gf2m.cpp:104
void swap(polyn_gf2m &other)
Definition: polyn_gf2m.cpp:790
std::shared_ptr< GF2m_Field > m_sp_field
Definition: polyn_gf2m.h:155
gf2m eval(gf2m a)
Definition: polyn_gf2m.cpp:254
void set_coef(size_t i, gf2m v)
Definition: polyn_gf2m.h:93