14606431966

Committed 22 Apr 2025 11:19PM UTC coverage: 91.416% (+0.1%) from 91.316%

Build # 14606431966

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Pull #4835

github

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web-flow

Commit Message

Merge f63084710 into 4c413a8ac

Pull Request Pull Request #4835: New Barrett Reduction implementation

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88.97

/src/lib/math/bigint/big_ops2.cpp

/*
* (C) 1999-2007,2018 Jack Lloyd
*     2016 Matthias Gierlings
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/bigint.h>

#include <botan/internal/bit_ops.h>
#include <botan/internal/mp_core.h>
#include <algorithm>

namespace Botan {

BigInt& BigInt::add(const word y[], size_t y_words, Sign y_sign) {
   const size_t x_sw = sig_words();

   grow_to(std::max(x_sw, y_words) + 1);

   if(sign() == y_sign) {
      bigint_add2(mutable_data(), size() - 1, y, y_words);
   } else {
      const int32_t relative_size = bigint_cmp(_data(), x_sw, y, y_words);

      if(relative_size >= 0) {
         // *this >= y
         bigint_sub2(mutable_data(), x_sw, y, y_words);
      } else {
         // *this < y
         bigint_sub2_rev(mutable_data(), y, y_words);
      }

      //this->sign_fixup(relative_size, y_sign);
      if(relative_size < 0) {
         set_sign(y_sign);
      } else if(relative_size == 0) {
         set_sign(Positive);
      }
   }

   return (*this);
}

BigInt& BigInt::mod_add(const BigInt& s, const BigInt& mod, secure_vector<word>& ws) {
   if(this->is_negative() || s.is_negative() || mod.is_negative()) {
      throw Invalid_Argument("BigInt::mod_add expects all arguments are positive");
   }

   BOTAN_DEBUG_ASSERT(*this < mod);
   BOTAN_DEBUG_ASSERT(s < mod);

   /*
   t + s or t + s - p == t - (p - s)

   So first compute ws = p - s

   Then compute t + s and t - ws

   If t - ws does not borrow, then that is the correct valued
   */

   const size_t mod_sw = mod.sig_words();
   BOTAN_ARG_CHECK(mod_sw > 0, "BigInt::mod_add modulus must be positive");

   this->grow_to(mod_sw);
   s.grow_to(mod_sw);

   // First mod_sw for p - s, 2*mod_sw for bigint_addsub workspace
   if(ws.size() < 3 * mod_sw) {
      ws.resize(3 * mod_sw);
   }

   word borrow = bigint_sub3(&ws[0], mod._data(), mod_sw, s._data(), mod_sw);
   BOTAN_DEBUG_ASSERT(borrow == 0);
   BOTAN_UNUSED(borrow);

   // Compute t - ws
   borrow = bigint_sub3(&ws[mod_sw], this->_data(), mod_sw, &ws[0], mod_sw);

   // Compute t + s
   bigint_add3_nc(&ws[mod_sw * 2], this->_data(), mod_sw, s._data(), mod_sw);

   CT::conditional_copy_mem(borrow, &ws[0], &ws[mod_sw * 2], &ws[mod_sw], mod_sw);
   set_words(&ws[0], mod_sw);

   return (*this);
}

BigInt& BigInt::mod_sub(const BigInt& s, const BigInt& mod, secure_vector<word>& ws) {
   if(this->is_negative() || s.is_negative() || mod.is_negative()) {
      throw Invalid_Argument("BigInt::mod_sub expects all arguments are positive");
   }

   // We are assuming in this function that *this and s are no more than mod_sw words long
   BOTAN_DEBUG_ASSERT(*this < mod);
   BOTAN_DEBUG_ASSERT(s < mod);

   const size_t mod_sw = mod.sig_words();

   this->grow_to(mod_sw);
   s.grow_to(mod_sw);

   if(ws.size() < mod_sw) {
      ws.resize(mod_sw);
   }

   bigint_mod_sub(mutable_data(), s._data(), mod._data(), mod_sw, ws.data());

   return (*this);
}

BigInt& BigInt::mod_mul(uint8_t y, const BigInt& mod, secure_vector<word>& ws) {
   BOTAN_ARG_CHECK(this->is_negative() == false, "*this must be positive");
   BOTAN_ARG_CHECK(y < 16, "y too large");

   BOTAN_DEBUG_ASSERT(*this < mod);

   *this *= static_cast<word>(y);
   this->reduce_below(mod, ws);
   return (*this);
}

BigInt& BigInt::rev_sub(const word y[], size_t y_sw, secure_vector<word>& ws) {
   if(this->sign() != BigInt::Positive) {
      throw Invalid_State("BigInt::sub_rev requires this is positive");
   }

   const size_t x_sw = this->sig_words();

   ws.resize(std::max(x_sw, y_sw));
   clear_mem(ws.data(), ws.size());

   const int32_t relative_size = bigint_sub_abs(ws.data(), _data(), x_sw, y, y_sw);

   this->cond_flip_sign(relative_size > 0);
   this->swap_reg(ws);

   return (*this);
}

/*
* Multiplication Operator
*/
BigInt& BigInt::operator*=(const BigInt& y) {
   secure_vector<word> ws;
   return this->mul(y, ws);
}

BigInt& BigInt::mul(const BigInt& y, secure_vector<word>& ws) {
   const size_t x_sw = sig_words();
   const size_t y_sw = y.sig_words();
   set_sign((sign() == y.sign()) ? Positive : Negative);

   if(x_sw == 0 || y_sw == 0) {
      clear();
      set_sign(Positive);
   } else if(x_sw == 1 && y_sw) {
      grow_to(y_sw + 1);
      bigint_linmul3(mutable_data(), y._data(), y_sw, word_at(0));
   } else if(y_sw == 1 && x_sw) {
      word carry = bigint_linmul2(mutable_data(), x_sw, y.word_at(0));
      set_word_at(x_sw, carry);
   } else {
      const size_t new_size = x_sw + y_sw + 1;
      if(ws.size() < new_size) {
         ws.resize(new_size);
      }
      secure_vector<word> z_reg(new_size);

      bigint_mul(z_reg.data(), z_reg.size(), _data(), size(), x_sw, y._data(), y.size(), y_sw, ws.data(), ws.size());

      this->swap_reg(z_reg);
   }

   return (*this);
}

BigInt& BigInt::square(secure_vector<word>& ws) {
   const size_t sw = sig_words();

   secure_vector<word> z(2 * sw);
   ws.resize(z.size());

   bigint_sqr(z.data(), z.size(), _data(), size(), sw, ws.data(), ws.size());

   swap_reg(z);
   set_sign(BigInt::Positive);

   return (*this);
}

BigInt& BigInt::operator*=(word y) {
   if(y == 0) {
      clear();
      set_sign(Positive);
   }

   const word carry = bigint_linmul2(mutable_data(), size(), y);
   set_word_at(size(), carry);

   return (*this);
}

/*
* Division Operator
*/
BigInt& BigInt::operator/=(const BigInt& y) {
   if(y.sig_words() == 1 && is_power_of_2(y.word_at(0))) {
      (*this) >>= (y.bits() - 1);
   } else {
      (*this) = (*this) / y;
   }
   return (*this);
}

/*
* Modulo Operator
*/
BigInt& BigInt::operator%=(const BigInt& mod) {
   return (*this = (*this) % mod);
}

/*
* Modulo Operator
*/
word BigInt::operator%=(word mod) {
   if(mod == 0) {
      throw Invalid_Argument("BigInt::operator%= divide by zero");
   }

   word remainder = 0;

   if(is_power_of_2(mod)) {
      remainder = (word_at(0) & (mod - 1));
   } else {
      const size_t sw = sig_words();
      for(size_t i = sw; i > 0; --i) {
         remainder = bigint_modop_vartime(remainder, word_at(i - 1), mod);
      }
   }

   if(remainder && sign() == BigInt::Negative) {
      remainder = mod - remainder;
   }

   m_data.set_to_zero();
   m_data.set_word_at(0, remainder);
   set_sign(BigInt::Positive);
   return remainder;
}

/*
* Left Shift Operator
*/
BigInt& BigInt::operator<<=(size_t shift) {
   const size_t sw = sig_words();
   const size_t new_size = sw + (shift + WordInfo<word>::bits - 1) / WordInfo<word>::bits;

   m_data.grow_to(new_size);

   bigint_shl1(m_data.mutable_data(), new_size, sw, shift);

   return (*this);
}

/*
* Right Shift Operator
*/
BigInt& BigInt::operator>>=(size_t shift) {
   bigint_shr1(m_data.mutable_data(), m_data.size(), shift);

   if(is_negative() && is_zero()) {
      set_sign(Positive);
   }

   return (*this);
}

}  // namespace Botan

1	/*
2	* (C) 1999-2007,2018 Jack Lloyd
3	* 2016 Matthias Gierlings
4	*
5	* Botan is released under the Simplified BSD License (see license.txt)
6	*/
7
8	#include <botan/bigint.h>
9
10	#include <botan/internal/bit_ops.h>
11	#include <botan/internal/mp_core.h>
12	#include <algorithm>
13
14	namespace Botan {
15
16	BigInt& BigInt::add(const word y[], size_t y_words, Sign y_sign) {	6,071,715✔
17	const size_t x_sw = sig_words();	6,071,715✔
18
19	grow_to(std::max(x_sw, y_words) + 1);	6,142,632✔
20
21	if(sign() == y_sign) {	6,071,715✔
22	bigint_add2(mutable_data(), size() - 1, y, y_words);	2,469,406✔
23	} else {
24	const int32_t relative_size = bigint_cmp(_data(), x_sw, y, y_words);	3,602,309✔
25
26	if(relative_size >= 0) {	3,602,309✔
27	// *this >= y
28	bigint_sub2(mutable_data(), x_sw, y, y_words);	3,544,006✔
29	} else {
30	// *this < y
31	bigint_sub2_rev(mutable_data(), y, y_words);	58,303✔
32	}
33
34	//this->sign_fixup(relative_size, y_sign);
35	if(relative_size < 0) {	3,602,309✔
36	set_sign(y_sign);	58,303✔
37	} else if(relative_size == 0) {	3,544,006✔
38	set_sign(Positive);	53,105✔
39	}
40	}
41
42	return (*this);	6,071,715✔
43	}
44
45	BigInt& BigInt::mod_add(const BigInt& s, const BigInt& mod, secure_vector<word>& ws) {	1,115,392✔
46	if(this->is_negative() \|\| s.is_negative() \|\| mod.is_negative()) {	1,115,392✔
47	throw Invalid_Argument("BigInt::mod_add expects all arguments are positive");	×
48	}
49
50	BOTAN_DEBUG_ASSERT(*this < mod);	1,115,392✔
51	BOTAN_DEBUG_ASSERT(s < mod);	1,115,392✔
52
53	/*
54	t + s or t + s - p == t - (p - s)
55
56	So first compute ws = p - s
57
58	Then compute t + s and t - ws
59
60	If t - ws does not borrow, then that is the correct valued
61	*/
62
63	const size_t mod_sw = mod.sig_words();	1,115,392✔
64	BOTAN_ARG_CHECK(mod_sw > 0, "BigInt::mod_add modulus must be positive");	1,115,392✔
65
66	this->grow_to(mod_sw);	1,115,392✔
67	s.grow_to(mod_sw);	1,115,392✔
68
69	// First mod_sw for p - s, 2*mod_sw for bigint_addsub workspace
70	if(ws.size() < 3 * mod_sw) {	1,115,392✔
71	ws.resize(3 * mod_sw);	614,864✔
72	}
73
74	word borrow = bigint_sub3(&ws[0], mod._data(), mod_sw, s._data(), mod_sw);	1,115,392✔
75	BOTAN_DEBUG_ASSERT(borrow == 0);	1,115,392✔
76	BOTAN_UNUSED(borrow);	1,115,392✔
77
78	// Compute t - ws
79	borrow = bigint_sub3(&ws[mod_sw], this->_data(), mod_sw, &ws[0], mod_sw);	1,115,392✔
80
81	// Compute t + s
82	bigint_add3_nc(&ws[mod_sw * 2], this->_data(), mod_sw, s._data(), mod_sw);	1,115,392✔
83
84	CT::conditional_copy_mem(borrow, &ws[0], &ws[mod_sw * 2], &ws[mod_sw], mod_sw);	1,115,392✔
85	set_words(&ws[0], mod_sw);	1,115,392✔
86
87	return (*this);	1,115,392✔
88	}
89
90	BigInt& BigInt::mod_sub(const BigInt& s, const BigInt& mod, secure_vector<word>& ws) {	15,863,593✔
91	if(this->is_negative() \|\| s.is_negative() \|\| mod.is_negative()) {	15,863,593✔
92	throw Invalid_Argument("BigInt::mod_sub expects all arguments are positive");	×
93	}
94
95	// We are assuming in this function that *this and s are no more than mod_sw words long
96	BOTAN_DEBUG_ASSERT(*this < mod);	15,863,593✔
97	BOTAN_DEBUG_ASSERT(s < mod);	15,863,593✔
98
99	const size_t mod_sw = mod.sig_words();	15,863,593✔
100
101	this->grow_to(mod_sw);	15,863,593✔
102	s.grow_to(mod_sw);	15,863,593✔
103
104	if(ws.size() < mod_sw) {	15,863,593✔
105	ws.resize(mod_sw);	5,997✔
106	}
107
108	bigint_mod_sub(mutable_data(), s._data(), mod._data(), mod_sw, ws.data());	15,863,593✔
109
110	return (*this);	15,863,593✔
111	}
112
113	BigInt& BigInt::mod_mul(uint8_t y, const BigInt& mod, secure_vector<word>& ws) {	6,908,632✔
114	BOTAN_ARG_CHECK(this->is_negative() == false, "*this must be positive");	6,908,632✔
115	BOTAN_ARG_CHECK(y < 16, "y too large");	6,908,632✔
116
117	BOTAN_DEBUG_ASSERT(*this < mod);	6,908,632✔
118
119	this = static_cast<word>(y);	6,908,632✔
120	this->reduce_below(mod, ws);	6,908,632✔
121	return (*this);	6,908,632✔
122	}
123
124	BigInt& BigInt::rev_sub(const word y[], size_t y_sw, secure_vector<word>& ws) {	×
125	if(this->sign() != BigInt::Positive) {	×
126	throw Invalid_State("BigInt::sub_rev requires this is positive");	×
127	}
128
129	const size_t x_sw = this->sig_words();	×
130
131	ws.resize(std::max(x_sw, y_sw));	×
132	clear_mem(ws.data(), ws.size());	×
133
134	const int32_t relative_size = bigint_sub_abs(ws.data(), _data(), x_sw, y, y_sw);	×
135
136	this->cond_flip_sign(relative_size > 0);	×
137	this->swap_reg(ws);	×
138
139	return (*this);	×
140	}
141
142	/*
143	* Multiplication Operator
144	*/
145	BigInt& BigInt::operator*=(const BigInt& y) {	530✔
146	secure_vector<word> ws;	530✔
147	return this->mul(y, ws);	530✔
148	}	530✔
149
150	BigInt& BigInt::mul(const BigInt& y, secure_vector<word>& ws) {	9,713✔
151	const size_t x_sw = sig_words();	9,713✔
152	const size_t y_sw = y.sig_words();	9,713✔
153	set_sign((sign() == y.sign()) ? Positive : Negative);	9,783✔
154
155	if(x_sw == 0 \|\| y_sw == 0) {	9,713✔
156	clear();	33✔
157	set_sign(Positive);	33✔
158	} else if(x_sw == 1 && y_sw) {	9,680✔
159	grow_to(y_sw + 1);	332✔
160	bigint_linmul3(mutable_data(), y._data(), y_sw, word_at(0));	664✔
161	} else if(y_sw == 1 && x_sw) {	9,348✔
162	word carry = bigint_linmul2(mutable_data(), x_sw, y.word_at(0));	42✔
163	set_word_at(x_sw, carry);	21✔
164	} else {
165	const size_t new_size = x_sw + y_sw + 1;	9,327✔
166	if(ws.size() < new_size) {	9,327✔
167	ws.resize(new_size);	9,327✔
168	}
169	secure_vector<word> z_reg(new_size);	9,327✔
170
171	bigint_mul(z_reg.data(), z_reg.size(), _data(), size(), x_sw, y._data(), y.size(), y_sw, ws.data(), ws.size());	9,327✔
172
173	this->swap_reg(z_reg);	9,327✔
174	}	9,327✔
175
176	return (*this);	9,713✔
177	}
178
179	BigInt& BigInt::square(secure_vector<word>& ws) {	10,204✔
180	const size_t sw = sig_words();	10,204✔
181
182	secure_vector<word> z(2 * sw);	10,204✔
183	ws.resize(z.size());	10,204✔
184
185	bigint_sqr(z.data(), z.size(), _data(), size(), sw, ws.data(), ws.size());	10,204✔
186
187	swap_reg(z);	10,204✔
188	set_sign(BigInt::Positive);	10,204✔
189
190	return (*this);	10,204✔
191	}	10,204✔
192
193	BigInt& BigInt::operator*=(word y) {	7,287,759✔
194	if(y == 0) {	7,287,759✔
195	clear();	×
196	set_sign(Positive);	×
197	}
198
199	const word carry = bigint_linmul2(mutable_data(), size(), y);	7,287,759✔
200	set_word_at(size(), carry);	7,287,759✔
201
202	return (*this);	7,287,759✔
203	}
204
205	/*
206	* Division Operator
207	*/
208	BigInt& BigInt::operator/=(const BigInt& y) {	929✔
209	if(y.sig_words() == 1 && is_power_of_2(y.word_at(0))) {	1,622✔
210	(*this) >>= (y.bits() - 1);	85✔
211	} else {
212	(this) = (this) / y;	844✔
213	}
214	return (*this);	929✔
215	}
216
217	/*
218	* Modulo Operator
219	*/
220	BigInt& BigInt::operator%=(const BigInt& mod) {	323,374✔
221	return (this = (this) % mod);	323,374✔
222	}
223
224	/*
225	* Modulo Operator
226	*/
227	word BigInt::operator%=(word mod) {	33✔
228	if(mod == 0) {	33✔
229	throw Invalid_Argument("BigInt::operator%= divide by zero");	×
230	}
231
232	word remainder = 0;	33✔
233
234	if(is_power_of_2(mod)) {	33✔
235	remainder = (word_at(0) & (mod - 1));	10✔
236	} else {
237	const size_t sw = sig_words();	28✔
238	for(size_t i = sw; i > 0; --i) {	79✔
239	remainder = bigint_modop_vartime(remainder, word_at(i - 1), mod);	102✔
240	}
241	}
242
243	if(remainder && sign() == BigInt::Negative) {	33✔
244	remainder = mod - remainder;	12✔
245	}
246
247	m_data.set_to_zero();	33✔
248	m_data.set_word_at(0, remainder);	33✔
249	set_sign(BigInt::Positive);	33✔
250	return remainder;	33✔
251	}
252
253	/*
254	* Left Shift Operator
255	*/
256	BigInt& BigInt::operator<<=(size_t shift) {	12,139,179✔
257	const size_t sw = sig_words();	12,139,179✔
258	const size_t new_size = sw + (shift + WordInfo<word>::bits - 1) / WordInfo<word>::bits;	12,139,179✔
259
260	m_data.grow_to(new_size);	12,139,179✔
261
262	bigint_shl1(m_data.mutable_data(), new_size, sw, shift);	12,139,179✔
263
264	return (*this);	12,139,179✔
265	}
266
267	/*
268	* Right Shift Operator
269	*/
270	BigInt& BigInt::operator>>=(size_t shift) {	8,085,829✔
271	bigint_shr1(m_data.mutable_data(), m_data.size(), shift);	8,085,829✔
272
273	if(is_negative() && is_zero()) {	8,180,012✔
274	set_sign(Positive);	8✔
275	}
276
277	return (*this);	8,085,829✔
278	}
279
280	} // namespace Botan

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