/src/botan/build/include/botan/dl_group.h

Source
/*
* Discrete Logarithm Group
* (C) 1999-2008,2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_DL_PARAM_H_
#define BOTAN_DL_PARAM_H_

#include <botan/bigint.h>
#include <string_view>

namespace Botan {

class Montgomery_Params;
class DL_Group_Data;

enum class DL_Group_Source {
   Builtin,
   RandomlyGenerated,
   ExternalSource,
};

/**
* The DL group encoding format variants.
*/
enum class DL_Group_Format {
   ANSI_X9_42,
   ANSI_X9_57,
   PKCS_3,

   DSA_PARAMETERS = ANSI_X9_57,
   DH_PARAMETERS = ANSI_X9_42,
   ANSI_X9_42_DH_PARAMETERS = ANSI_X9_42,
   PKCS3_DH_PARAMETERS = PKCS_3
};

/**
* This class represents discrete logarithm groups. It holds a prime
* modulus p, a generator g, and (optionally) a prime q which is a
* factor of (p-1). In most cases g generates the order-q subgroup.
*/
class BOTAN_PUBLIC_API(2, 0) DL_Group final {
   public:
      /**
      * Determine the prime creation for DL groups.
      */
      enum PrimeType { Strong, Prime_Subgroup, DSA_Kosherizer };

      using Format = DL_Group_Format;

      /**
      * Construct a DL group with uninitialized internal value.
      * Use this constructor is you wish to set the groups values
      * from a DER or PEM encoded group.
      */
      DL_Group() = default;

      /**
      * Construct a DL group that is registered in the configuration.
      * @param name the name of the group, for example "modp/ietf/3072"
      *
      * @warning This constructor also accepts PEM inputs. This behavior is
      * deprecated and will be removed in a future major release. Instead
      * use DL_Group_from_PEM function
      */
      explicit DL_Group(std::string_view name);

      /*
      * Read a PEM representation
      */
      static DL_Group DL_Group_from_PEM(std::string_view pem);

      /**
      * Create a new group randomly.
      * @param rng the random number generator to use
      * @param type specifies how the creation of primes p and q shall
      * be performed. If type=Strong, then p will be determined as a
      * safe prime, and q will be chosen as (p-1)/2. If
      * type=Prime_Subgroup and qbits = 0, then the size of q will be
      * determined according to the estimated difficulty of the DL
      * problem. If type=DSA_Kosherizer, DSA primes will be created.
      * @param pbits the number of bits of p
      * @param qbits the number of bits of q. Leave it as 0 to have
      * the value determined according to pbits.
      */
      DL_Group(RandomNumberGenerator& rng, PrimeType type, size_t pbits, size_t qbits = 0);

      /**
      * Create a DSA group with a given seed.
      * @param rng the random number generator to use
      * @param seed the seed to use to create the random primes
      * @param pbits the desired bit size of the prime p
      * @param qbits the desired bit size of the prime q.
      */
      DL_Group(RandomNumberGenerator& rng, const std::vector<uint8_t>& seed, size_t pbits = 1024, size_t qbits = 0);

      /**
      * Create a DL group.
      * @param p the prime p
      * @param g the base g
      */
      DL_Group(const BigInt& p, const BigInt& g);

      /**
      * Create a DL group.
      * @param p the prime p
      * @param q the prime q
      * @param g the base g
      */
      DL_Group(const BigInt& p, const BigInt& q, const BigInt& g);

      /**
      * Decode a BER-encoded DL group param
      */
      DL_Group(const uint8_t ber[], size_t ber_len, DL_Group_Format format);

      /**
      * Decode a BER-encoded DL group param
      */
      template <typename Alloc>
      DL_Group(const std::vector<uint8_t, Alloc>& ber, DL_Group_Format format) :
            DL_Group(ber.data(), ber.size(), format) {}

      /**
      * Get the prime p.
      * @return prime p
      */
      const BigInt& get_p() const;

      /**
      * Get the prime q, returns zero if q is not used
      * @return prime q
      */
      const BigInt& get_q() const;

      /**
      * Get the base g.
      * @return base g
      */
      const BigInt& get_g() const;

      /**
      * Perform validity checks on the group.
      * @param rng the rng to use
      * @param strong whether to perform stronger by lengthier tests
      * @return true if the object is consistent, false otherwise
      */
      bool verify_group(RandomNumberGenerator& rng, bool strong = true) const;

      /**
      * Verify a public element, ie check if y = g^x for some x.
      *
      * This is not a perfect test. It verifies that 1 < y < p and (if q is set)
      * that y is in the subgroup of size q.
      */
      bool verify_public_element(const BigInt& y) const;

      /**
      * Verify a private element
      *
      * Specifically this checks that x is > 1 and < p, and additionally if
      * q is set then x must be < q
      */
      bool verify_private_element(const BigInt& x) const;

      /**
      * Verify a pair of elements y = g^x
      *
      * This verifies that 1 < x,y < p and that y=g^x mod p
      */
      bool verify_element_pair(const BigInt& y, const BigInt& x) const;

      /**
      * Encode this group into a string using PEM encoding.
      * @param format the encoding format
      * @return string holding the PEM encoded group
      */
      std::string PEM_encode(DL_Group_Format format) const;

      /**
      * Encode this group into a string using DER encoding.
      * @param format the encoding format
      * @return string holding the DER encoded group
      */
      std::vector<uint8_t> DER_encode(DL_Group_Format format) const;

      /**
      * Reduce an integer modulo p
      * @return x % p
      */
      BigInt mod_p(const BigInt& x) const;

      /**
      * Multiply and reduce an integer modulo p
      * @return (x*y) % p
      */
      BigInt multiply_mod_p(const BigInt& x, const BigInt& y) const;

      /**
      * Return the inverse of x mod p
      */
      BigInt inverse_mod_p(const BigInt& x) const;

      /**
      * Reduce an integer modulo q
      * Throws if q is unset on this DL_Group
      * @return x % q
      */
      BigInt mod_q(const BigInt& x) const;

      /**
      * Multiply and reduce an integer modulo q
      * Throws if q is unset on this DL_Group
      * @return (x*y) % q
      */
      BigInt multiply_mod_q(const BigInt& x, const BigInt& y) const;

      /**
      * Multiply and reduce an integer modulo q
      * Throws if q is unset on this DL_Group
      * @return (x*y*z) % q
      */
      BigInt multiply_mod_q(const BigInt& x, const BigInt& y, const BigInt& z) const;

      /**
      * Square and reduce an integer modulo q
      * Throws if q is unset on this DL_Group
      * @return (x*x) % q
      */
      BigInt square_mod_q(const BigInt& x) const;

      /**
      * Return the inverse of x mod q
      * Throws if q is unset on this DL_Group
      */
      BigInt inverse_mod_q(const BigInt& x) const;

      /**
      * Modular exponentiation
      *
      * @warning this function leaks the size of x via the number of
      * loop iterations. Use the version taking the maximum size to
      * avoid this.
      *
      * @return (g^x) % p
      */
      BigInt power_g_p(const BigInt& x) const;

      /**
      * Modular exponentiation
      * @param x the exponent
      * @param max_x_bits x is assumed to be at most this many bits long.
      *
      * @return (g^x) % p
      */
      BigInt power_g_p(const BigInt& x, size_t max_x_bits) const;

      /**
      * Modular exponentiation
      * @param b the base
      * @param x the exponent
      * @param max_x_bits x is assumed to be at most this many bits long.
      *
      * @return (b^x) % p
      */
      BigInt power_b_p(const BigInt& b, const BigInt& x, size_t max_x_bits) const;

      /**
      * Modular exponentiation
      * @param b the base
      * @param x the exponent
      *
      * @return (b^x) % p
      */
      BigInt power_b_p(const BigInt& b, const BigInt& x) const;

      /**
      * Multi-exponentiate
      * Return (g^x * y^z) % p
      */
      BigInt multi_exponentiate(const BigInt& x, const BigInt& y, const BigInt& z) const;

      /**
      * Return parameters for Montgomery reduction/exponentiation mod p
      */
      std::shared_ptr<const Montgomery_Params> monty_params_p() const;

      /**
      * Return the size of p in bits
      * Same as get_p().bits()
      */
      size_t p_bits() const;

      /**
      * Return the size of p in bytes
      * Same as get_p().bytes()
      */
      size_t p_bytes() const;

      /**
      * Return the size of q in bits
      * Same as get_q().bits()
      * Throws if q is unset
      */
      size_t q_bits() const;

      /**
      * Return the size of q in bytes
      * Same as get_q().bytes()
      * Throws if q is unset
      */
      size_t q_bytes() const;

      /**
      * Return if the q value is set
      */
      bool has_q() const;

      /**
      * Return size in bits of a secret exponent
      *
      * This attempts to balance between the attack costs of NFS
      * (which depends on the size of the modulus) and Pollard's rho
      * (which depends on the size of the exponent).
      *
      * It may vary over time for a particular group, if the attack
      * costs change.
      */
      size_t exponent_bits() const;

      /**
      * Return an estimate of the strength of this group against
      * discrete logarithm attacks (eg NFS). Warning: since this only
      * takes into account known attacks it is by necessity an
      * overestimate of the actual strength.
      */
      size_t estimated_strength() const;

      /**
      * Decode a DER/BER encoded group into this instance.
      * @param ber a vector containing the DER/BER encoded group
      * @param format the format of the encoded group
      *
      * @warning avoid this. Instead use the DL_Group constructor
      */
      void BER_decode(const std::vector<uint8_t>& ber, DL_Group_Format format);

      DL_Group_Source source() const;

      /*
      * For internal use only
      */
      static std::shared_ptr<DL_Group_Data> DL_group_info(std::string_view name);

   private:
      static std::shared_ptr<DL_Group_Data> load_DL_group_info(const char* p_str, const char* q_str, const char* g_str);

      static std::shared_ptr<DL_Group_Data> load_DL_group_info(const char* p_str, const char* g_str);

      static std::shared_ptr<DL_Group_Data> BER_decode_DL_group(const uint8_t data[],
                                                                size_t data_len,
                                                                DL_Group_Format format,
                                                                DL_Group_Source source);

      const DL_Group_Data& data() const;
      std::shared_ptr<DL_Group_Data> m_data;
};

}  // namespace Botan

#endif

Coverage Report

Created: 2023-06-07 07:01

Line	Count	Source
1		/*
2		* Discrete Logarithm Group
3		* (C) 1999-2008,2018 Jack Lloyd
4		*
5		* Botan is released under the Simplified BSD License (see license.txt)
6		*/
7
8		#ifndef BOTAN_DL_PARAM_H_
9		#define BOTAN_DL_PARAM_H_
10
11		#include <botan/bigint.h>
12		#include <string_view>
13
14		namespace Botan {
15
16		class Montgomery_Params;
17		class DL_Group_Data;
18
19		enum class DL_Group_Source {
20		Builtin,
21		RandomlyGenerated,
22		ExternalSource,
23		};
24
25		/**
26		* The DL group encoding format variants.
27		*/
28		enum class DL_Group_Format {
29		ANSI_X9_42,
30		ANSI_X9_57,
31		PKCS_3,
32
33		DSA_PARAMETERS = ANSI_X9_57,
34		DH_PARAMETERS = ANSI_X9_42,
35		ANSI_X9_42_DH_PARAMETERS = ANSI_X9_42,
36		PKCS3_DH_PARAMETERS = PKCS_3
37		};
38
39		/**
40		* This class represents discrete logarithm groups. It holds a prime
41		* modulus p, a generator g, and (optionally) a prime q which is a
42		* factor of (p-1). In most cases g generates the order-q subgroup.
43		*/
44		class BOTAN_PUBLIC_API(2, 0) DL_Group final {
45		public:
46		/**
47		* Determine the prime creation for DL groups.
48		*/
49		enum PrimeType { Strong, Prime_Subgroup, DSA_Kosherizer };
50
51		using Format = DL_Group_Format;
52
53		/**
54		* Construct a DL group with uninitialized internal value.
55		* Use this constructor is you wish to set the groups values
56		* from a DER or PEM encoded group.
57		*/
58		DL_Group() = default;
59
60		/**
61		* Construct a DL group that is registered in the configuration.
62		* @param name the name of the group, for example "modp/ietf/3072"
63		*
64		* @warning This constructor also accepts PEM inputs. This behavior is
65		* deprecated and will be removed in a future major release. Instead
66		* use DL_Group_from_PEM function
67		*/
68		explicit DL_Group(std::string_view name);
69
70		/*
71		* Read a PEM representation
72		*/
73		static DL_Group DL_Group_from_PEM(std::string_view pem);
74
75		/**
76		* Create a new group randomly.
77		* @param rng the random number generator to use
78		* @param type specifies how the creation of primes p and q shall
79		* be performed. If type=Strong, then p will be determined as a
80		* safe prime, and q will be chosen as (p-1)/2. If
81		* type=Prime_Subgroup and qbits = 0, then the size of q will be
82		* determined according to the estimated difficulty of the DL
83		* problem. If type=DSA_Kosherizer, DSA primes will be created.
84		* @param pbits the number of bits of p
85		* @param qbits the number of bits of q. Leave it as 0 to have
86		* the value determined according to pbits.
87		*/
88		DL_Group(RandomNumberGenerator& rng, PrimeType type, size_t pbits, size_t qbits = 0);
89
90		/**
91		* Create a DSA group with a given seed.
92		* @param rng the random number generator to use
93		* @param seed the seed to use to create the random primes
94		* @param pbits the desired bit size of the prime p
95		* @param qbits the desired bit size of the prime q.
96		*/
97		DL_Group(RandomNumberGenerator& rng, const std::vector<uint8_t>& seed, size_t pbits = 1024, size_t qbits = 0);
98
99		/**
100		* Create a DL group.
101		* @param p the prime p
102		* @param g the base g
103		*/
104		DL_Group(const BigInt& p, const BigInt& g);
105
106		/**
107		* Create a DL group.
108		* @param p the prime p
109		* @param q the prime q
110		* @param g the base g
111		*/
112		DL_Group(const BigInt& p, const BigInt& q, const BigInt& g);
113
114		/**
115		* Decode a BER-encoded DL group param
116		*/
117		DL_Group(const uint8_t ber[], size_t ber_len, DL_Group_Format format);
118
119		/**
120		* Decode a BER-encoded DL group param
121		*/
122		template <typename Alloc>
123		DL_Group(const std::vector<uint8_t, Alloc>& ber, DL_Group_Format format) :
124	489	DL_Group(ber.data(), ber.size(), format) {}
125
126		/**
127		* Get the prime p.
128		* @return prime p
129		*/
130		const BigInt& get_p() const;
131
132		/**
133		* Get the prime q, returns zero if q is not used
134		* @return prime q
135		*/
136		const BigInt& get_q() const;
137
138		/**
139		* Get the base g.
140		* @return base g
141		*/
142		const BigInt& get_g() const;
143
144		/**
145		* Perform validity checks on the group.
146		* @param rng the rng to use
147		* @param strong whether to perform stronger by lengthier tests
148		* @return true if the object is consistent, false otherwise
149		*/
150		bool verify_group(RandomNumberGenerator& rng, bool strong = true) const;
151
152		/**
153		* Verify a public element, ie check if y = g^x for some x.
154		*
155		* This is not a perfect test. It verifies that 1 < y < p and (if q is set)
156		* that y is in the subgroup of size q.
157		*/
158		bool verify_public_element(const BigInt& y) const;
159
160		/**
161		* Verify a private element
162		*
163		* Specifically this checks that x is > 1 and < p, and additionally if
164		* q is set then x must be < q
165		*/
166		bool verify_private_element(const BigInt& x) const;
167
168		/**
169		* Verify a pair of elements y = g^x
170		*
171		* This verifies that 1 < x,y < p and that y=g^x mod p
172		*/
173		bool verify_element_pair(const BigInt& y, const BigInt& x) const;
174
175		/**
176		* Encode this group into a string using PEM encoding.
177		* @param format the encoding format
178		* @return string holding the PEM encoded group
179		*/
180		std::string PEM_encode(DL_Group_Format format) const;
181
182		/**
183		* Encode this group into a string using DER encoding.
184		* @param format the encoding format
185		* @return string holding the DER encoded group
186		*/
187		std::vector<uint8_t> DER_encode(DL_Group_Format format) const;
188
189		/**
190		* Reduce an integer modulo p
191		* @return x % p
192		*/
193		BigInt mod_p(const BigInt& x) const;
194
195		/**
196		* Multiply and reduce an integer modulo p
197		* @return (x*y) % p
198		*/
199		BigInt multiply_mod_p(const BigInt& x, const BigInt& y) const;
200
201		/**
202		* Return the inverse of x mod p
203		*/
204		BigInt inverse_mod_p(const BigInt& x) const;
205
206		/**
207		* Reduce an integer modulo q
208		* Throws if q is unset on this DL_Group
209		* @return x % q
210		*/
211		BigInt mod_q(const BigInt& x) const;
212
213		/**
214		* Multiply and reduce an integer modulo q
215		* Throws if q is unset on this DL_Group
216		* @return (x*y) % q
217		*/
218		BigInt multiply_mod_q(const BigInt& x, const BigInt& y) const;
219
220		/**
221		* Multiply and reduce an integer modulo q
222		* Throws if q is unset on this DL_Group
223		* @return (xyz) % q
224		*/
225		BigInt multiply_mod_q(const BigInt& x, const BigInt& y, const BigInt& z) const;
226
227		/**
228		* Square and reduce an integer modulo q
229		* Throws if q is unset on this DL_Group
230		* @return (x*x) % q
231		*/
232		BigInt square_mod_q(const BigInt& x) const;
233
234		/**
235		* Return the inverse of x mod q
236		* Throws if q is unset on this DL_Group
237		*/
238		BigInt inverse_mod_q(const BigInt& x) const;
239
240		/**
241		* Modular exponentiation
242		*
243		* @warning this function leaks the size of x via the number of
244		* loop iterations. Use the version taking the maximum size to
245		* avoid this.
246		*
247		* @return (g^x) % p
248		*/
249		BigInt power_g_p(const BigInt& x) const;
250
251		/**
252		* Modular exponentiation
253		* @param x the exponent
254		* @param max_x_bits x is assumed to be at most this many bits long.
255		*
256		* @return (g^x) % p
257		*/
258		BigInt power_g_p(const BigInt& x, size_t max_x_bits) const;
259
260		/**
261		* Modular exponentiation
262		* @param b the base
263		* @param x the exponent
264		* @param max_x_bits x is assumed to be at most this many bits long.
265		*
266		* @return (b^x) % p
267		*/
268		BigInt power_b_p(const BigInt& b, const BigInt& x, size_t max_x_bits) const;
269
270		/**
271		* Modular exponentiation
272		* @param b the base
273		* @param x the exponent
274		*
275		* @return (b^x) % p
276		*/
277		BigInt power_b_p(const BigInt& b, const BigInt& x) const;
278
279		/**
280		* Multi-exponentiate
281		* Return (g^x * y^z) % p
282		*/
283		BigInt multi_exponentiate(const BigInt& x, const BigInt& y, const BigInt& z) const;
284
285		/**
286		* Return parameters for Montgomery reduction/exponentiation mod p
287		*/
288		std::shared_ptr<const Montgomery_Params> monty_params_p() const;
289
290		/**
291		* Return the size of p in bits
292		* Same as get_p().bits()
293		*/
294		size_t p_bits() const;
295
296		/**
297		* Return the size of p in bytes
298		* Same as get_p().bytes()
299		*/
300		size_t p_bytes() const;
301
302		/**
303		* Return the size of q in bits
304		* Same as get_q().bits()
305		* Throws if q is unset
306		*/
307		size_t q_bits() const;
308
309		/**
310		* Return the size of q in bytes
311		* Same as get_q().bytes()
312		* Throws if q is unset
313		*/
314		size_t q_bytes() const;
315
316		/**
317		* Return if the q value is set
318		*/
319		bool has_q() const;
320
321		/**
322		* Return size in bits of a secret exponent
323		*
324		* This attempts to balance between the attack costs of NFS
325		* (which depends on the size of the modulus) and Pollard's rho
326		* (which depends on the size of the exponent).
327		*
328		* It may vary over time for a particular group, if the attack
329		* costs change.
330		*/
331		size_t exponent_bits() const;
332
333		/**
334		* Return an estimate of the strength of this group against
335		* discrete logarithm attacks (eg NFS). Warning: since this only
336		* takes into account known attacks it is by necessity an
337		* overestimate of the actual strength.
338		*/
339		size_t estimated_strength() const;
340
341		/**
342		* Decode a DER/BER encoded group into this instance.
343		* @param ber a vector containing the DER/BER encoded group
344		* @param format the format of the encoded group
345		*
346		* @warning avoid this. Instead use the DL_Group constructor
347		*/
348		void BER_decode(const std::vector<uint8_t>& ber, DL_Group_Format format);
349
350		DL_Group_Source source() const;
351
352		/*
353		* For internal use only
354		*/
355		static std::shared_ptr<DL_Group_Data> DL_group_info(std::string_view name);
356
357		private:
358		static std::shared_ptr<DL_Group_Data> load_DL_group_info(const char* p_str, const char* q_str, const char* g_str);
359
360		static std::shared_ptr<DL_Group_Data> load_DL_group_info(const char* p_str, const char* g_str);
361
362		static std::shared_ptr<DL_Group_Data> BER_decode_DL_group(const uint8_t data[],
363		size_t data_len,
364		DL_Group_Format format,
365		DL_Group_Source source);
366
367		const DL_Group_Data& data() const;
368		std::shared_ptr<DL_Group_Data> m_data;
369		};
370
371		} // namespace Botan
372
373		#endif