Botan  2.12.1
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 
35  :m_deg(-1) {}
36 
37  polyn_gf2m(const secure_vector<uint8_t>& encoded, std::shared_ptr<GF2m_Field> sp_field );
38 
39  polyn_gf2m& operator=(const polyn_gf2m&) = default;
40 
41  bool operator==(const polyn_gf2m & other) const ;
42 
43  bool operator!=(const polyn_gf2m & other) const { return !(*this == other); }
44 
46  {
47  this->swap(other);
48  }
49 
51  {
52  if(this != &other)
53  {
54  this->swap(other);
55  }
56  return *this;
57  }
58 
59  void swap(polyn_gf2m& other);
60 
62  /**
63  * create zero polynomial with reservation of space for a degree d polynomial
64  */
65  polyn_gf2m(int d, std::shared_ptr<GF2m_Field> sp_field);
66 
67  polyn_gf2m(polyn_gf2m const& other);
68  /**
69  * create zero polynomial with allocated size determined by specified degree d:
70  */
71 
72  /**
73  * random irreducible polynomial of degree t
74  */
75  polyn_gf2m(int t, RandomNumberGenerator& rng, std::shared_ptr<GF2m_Field> sp_field);
76 
77  std::shared_ptr<GF2m_Field> get_sp_field() const
78  { return m_sp_field; }
79 
80  gf2m& operator[](size_t i) { return coeff[i]; }
81 
82  gf2m operator[](size_t i) const { return coeff[i]; }
83 
84  gf2m get_lead_coef() const { return coeff[m_deg]; }
85 
86  gf2m get_coef(uint32_t i) const { return coeff[i]; }
87 
88  inline void set_coef(uint32_t i, gf2m v)
89  {
90  coeff[i] = v;
91  }
92 
93  inline void add_to_coef(uint32_t i, gf2m v)
94  {
95  coeff[i] = coeff[i] ^ v;
96  }
97 
98  std::string to_string() const;
99 
100  /** decode a polynomial from memory: **/
101  polyn_gf2m(const uint8_t* mem, uint32_t mem_len, std::shared_ptr<GF2m_Field> sp_field);
102  // remove one! ^v!
103  /**
104  * create a polynomial from memory area (encoded)
105  */
106  polyn_gf2m(int degree, const unsigned char* mem, uint32_t mem_byte_len, std::shared_ptr<GF2m_Field> sp_field);
107 
108  void encode(uint32_t min_numo_coeffs, uint8_t* mem, uint32_t mem_len) const;
109 
110  int get_degree() const;
111 
112  /**
113  * determine the degree in a timing secure manner. the timing of this function
114  * only depends on the number of allocated coefficients, not on the actual
115  * degree
116  */
117  int calc_degree_secure() const;
118 
119  void degppf(const polyn_gf2m & g, int* p_result);
120 
121  static std::vector<polyn_gf2m> sqmod_init(const polyn_gf2m & g);
122 
123  static std::vector<polyn_gf2m> sqrt_mod_init(const polyn_gf2m & g);
124 
125 
126  polyn_gf2m sqmod(const std::vector<polyn_gf2m> & sq, int d);
127  void set_to_zero();
128  gf2m eval(gf2m a);
129 
130  static std::pair<polyn_gf2m, polyn_gf2m> eea_with_coefficients(const polyn_gf2m & p,
131  const polyn_gf2m & g,
132  int break_deg);
133 
134  void patchup_deg_secure( uint32_t trgt_deg, volatile gf2m patch_elem);
135 
136  private:
137 
138  void set_degree(int d) { m_deg = d; }
139 
140  void poly_shiftmod( const polyn_gf2m & g);
141  void realloc(uint32_t new_size);
142  static polyn_gf2m gcd(polyn_gf2m const& p1, polyn_gf2m const& p2);
143 
144  /**
145  * destructive:
146  */
147  static void remainder(polyn_gf2m & p, const polyn_gf2m & g);
148 
149  static polyn_gf2m gcd_aux(polyn_gf2m& p1, polyn_gf2m& p2);
150  public:
151  // public member variable:
152  int m_deg;
153 
154  // public member variable:
156 
157  // public member variable:
158  std::shared_ptr<GF2m_Field> m_sp_field;
159  };
160 
163 
164 std::vector<polyn_gf2m> syndrome_init(polyn_gf2m const& generator, std::vector<gf2m> const& support, int n);
165 
166 /**
167 * Find the roots of a polynomial over GF(2^m) using the method by Federenko
168 * et al.
169 */
171 
172 }
173 
174 #endif
int get_degree() const
Definition: polyn_gf2m.cpp:228
int calc_degree_secure() const
Definition: polyn_gf2m.cpp:46
gf2m get_lead_coef() const
Definition: polyn_gf2m.h:84
gf2m & operator[](size_t i)
Definition: polyn_gf2m.h:80
bool operator==(const polyn_gf2m &other) const
Definition: polyn_gf2m.cpp:796
void set_coef(uint32_t i, gf2m v)
Definition: polyn_gf2m.h:88
polyn_gf2m sqmod(const std::vector< polyn_gf2m > &sq, int d)
Definition: polyn_gf2m.cpp:323
void degppf(const polyn_gf2m &g, int *p_result)
Definition: polyn_gf2m.cpp:390
static std::vector< polyn_gf2m > sqrt_mod_init(const polyn_gf2m &g)
Definition: polyn_gf2m.cpp:675
polyn_gf2m & operator=(polyn_gf2m &&other)
Definition: polyn_gf2m.h:50
gf2m get_coef(uint32_t i) const
Definition: polyn_gf2m.h:86
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
secure_vector< gf2m > find_roots_gf2m_decomp(const polyn_gf2m &polyn, uint32_t code_length)
Definition: alg_id.cpp:13
polyn_gf2m(polyn_gf2m &&other)
Definition: polyn_gf2m.h:45
bool operator!=(const polyn_gf2m &other) const
Definition: polyn_gf2m.h:43
static std::vector< polyn_gf2m > sqmod_init(const polyn_gf2m &g)
Definition: polyn_gf2m.cpp:289
secure_vector< gf2m > coeff
Definition: polyn_gf2m.h:155
gf2m operator[](size_t i) const
Definition: polyn_gf2m.h:82
gf2m random_code_element(unsigned code_length, RandomNumberGenerator &rng)
Definition: polyn_gf2m.cpp:71
uint32_t code_length
std::vector< polyn_gf2m > syndrome_init(polyn_gf2m const &generator, std::vector< gf2m > const &support, int n)
Definition: polyn_gf2m.cpp:720
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
void add_to_coef(uint32_t i, gf2m v)
Definition: polyn_gf2m.h:93
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:77
secure_vector< uint8_t > encode() const
Definition: polyn_gf2m.cpp:768
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:789
std::shared_ptr< GF2m_Field > m_sp_field
Definition: polyn_gf2m.h:158
gf2m eval(gf2m a)
Definition: polyn_gf2m.cpp:254