Coverage Report

Created: 2020-02-14 15:38

/src/botan/build/include/botan/polyn_gf2m.h
Line
Count
Source (jump to first uncovered line)
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
26
class polyn_gf2m
27
   {
28
   public:
29
      /**
30
      * create a zero polynomial:
31
      */
32
      explicit polyn_gf2m(std::shared_ptr<GF2m_Field> sp_field);
33
34
0
      polyn_gf2m() : m_deg(-1) {}
35
36
      polyn_gf2m(const secure_vector<uint8_t>& encoded, std::shared_ptr<GF2m_Field> sp_field);
37
38
0
      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
0
      bool operator!=(const polyn_gf2m & other) const { return !(*this == other); }
63
64
      polyn_gf2m(polyn_gf2m&& other)
65
0
         {
66
0
         this->swap(other);
67
0
         }
68
69
      polyn_gf2m & operator=(polyn_gf2m&& other)
70
0
         {
71
0
         if(this != &other)
72
0
            {
73
0
            this->swap(other);
74
0
            }
75
0
         return *this;
76
0
         }
77
78
      void swap(polyn_gf2m& other);
79
80
      secure_vector<uint8_t> encode() const;
81
82
      std::shared_ptr<GF2m_Field> get_sp_field() const
83
0
         { return m_sp_field; }
84
85
0
      gf2m& operator[](size_t i) { return coeff[i]; }
86
87
0
      gf2m operator[](size_t i) const { return coeff[i]; }
88
89
0
      gf2m get_lead_coef() const { return coeff[m_deg]; }
90
91
0
      gf2m get_coef(size_t i) const { return coeff[i]; }
92
93
      inline void set_coef(size_t i, gf2m v)
94
0
         {
95
0
         coeff[i] = v;
96
0
         }
97
98
      inline void add_to_coef(size_t i, gf2m v)
99
0
         {
100
0
         coeff[i] ^= v;
101
0
         }
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
0
      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:
152
      secure_vector<gf2m> coeff;
153
154
      // public member variable:
155
      std::shared_ptr<GF2m_Field> m_sp_field;
156
   };
157
158
gf2m random_gf2m(RandomNumberGenerator& rng);
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