Botan  2.18.2
Crypto and TLS for C++11
Classes | Public Types | Public Member Functions | Static Public Member Functions | List of all members
Botan::BigInt Class Referencefinal

#include <bigint.h>

Classes

class  DivideByZero
 

Public Types

enum  Base { Decimal = 10, Hexadecimal = 16, Binary = 256 }
 
enum  Sign { Negative = 0, Positive = 1 }
 

Public Member Functions

BigInt abs () const
 
BigIntadd (const word y[], size_t y_words, Sign sign)
 
 BigInt ()=default
 
 BigInt (uint64_t n)
 
 BigInt (const BigInt &other)=default
 
 BigInt (const std::string &str)
 
 BigInt (const uint8_t buf[], size_t length)
 
template<typename Alloc >
 BigInt (const std::vector< uint8_t, Alloc > &vec)
 
 BigInt (const uint8_t buf[], size_t length, Base base)
 
 BigInt (const uint8_t buf[], size_t length, size_t max_bits)
 
 BigInt (const word words[], size_t length)
 
 BigInt (RandomNumberGenerator &rng, size_t bits, bool set_high_bit=true)
 Create a random BigInt of the specified size. More...
 
 BigInt (Sign sign, size_t n)
 
 BigInt (BigInt &&other)
 
void binary_decode (const uint8_t buf[], size_t length)
 
template<typename Alloc >
void binary_decode (const std::vector< uint8_t, Alloc > &buf)
 
void binary_encode (uint8_t buf[]) const
 
void binary_encode (uint8_t buf[], size_t len) const
 
size_t bits () const
 
uint8_t byte_at (size_t n) const
 
size_t bytes () const
 
void clear ()
 
void clear_bit (size_t n)
 
int32_t cmp (const BigInt &n, bool check_signs=true) const
 
int32_t cmp_word (word n) const
 
void cond_flip_sign (bool predicate)
 
void conditionally_set_bit (size_t n, bool set_it)
 
void const_time_poison () const
 
void const_time_unpoison () const
 
void ct_cond_add (bool predicate, const BigInt &value)
 
void ct_cond_assign (bool predicate, const BigInt &other)
 
void ct_cond_swap (bool predicate, BigInt &other)
 
void ct_reduce_below (const BigInt &mod, secure_vector< word > &ws, size_t bound)
 
const word * data () const
 
void encode_words (word out[], size_t size) const
 
size_t encoded_size (Base base=Binary) const
 
void flip_sign ()
 
bool get_bit (size_t n) const
 
uint32_t get_substring (size_t offset, size_t length) const
 
secure_vector< word > & get_word_vector ()
 
const secure_vector< word > & get_word_vector () const
 
void grow_to (size_t n) const
 
bool is_equal (const BigInt &n) const
 
bool is_even () const
 
bool is_less_than (const BigInt &n) const
 
bool is_negative () const
 
bool is_nonzero () const
 
bool is_odd () const
 
bool is_positive () const
 
bool is_zero () const
 
void mask_bits (size_t n)
 
BigIntmod_add (const BigInt &y, const BigInt &mod, secure_vector< word > &ws)
 
BigIntmod_mul (uint8_t y, const BigInt &mod, secure_vector< word > &ws)
 
BigIntmod_sub (const BigInt &y, const BigInt &mod, secure_vector< word > &ws)
 
BigIntmul (const BigInt &y, secure_vector< word > &ws)
 
word * mutable_data ()
 
bool operator! () const
 
BigIntoperator%= (const BigInt &y)
 
word operator%= (word y)
 
BigIntoperator*= (const BigInt &y)
 
BigIntoperator*= (word y)
 
BigIntoperator++ ()
 
BigInt operator++ (int)
 
BigIntoperator+= (const BigInt &y)
 
BigIntoperator+= (word y)
 
BigInt operator- () const
 
BigIntoperator-- ()
 
BigInt operator-- (int)
 
BigIntoperator-= (const BigInt &y)
 
BigIntoperator-= (word y)
 
BigIntoperator/= (const BigInt &y)
 
BigIntoperator<<= (size_t shift)
 
BigIntoperator= (BigInt &&other)
 
BigIntoperator= (const BigInt &)=default
 
BigIntoperator>>= (size_t shift)
 
void randomize (RandomNumberGenerator &rng, size_t bitsize, bool set_high_bit=true)
 
size_t reduce_below (const BigInt &mod, secure_vector< word > &ws)
 
void resize (size_t s)
 
BigIntrev_sub (const word y[], size_t y_words, secure_vector< word > &ws)
 
Sign reverse_sign () const
 
void set_bit (size_t n)
 
void set_sign (Sign sign)
 
void set_word_at (size_t i, word w)
 
void set_words (const word w[], size_t len)
 
void shrink_to_fit (size_t min_size=0)
 
size_t sig_words () const
 
Sign sign () const
 
size_t size () const
 
BigIntsquare (secure_vector< word > &ws)
 
BigIntsub (const word y[], size_t y_words, Sign sign)
 
void swap (BigInt &other)
 
void swap_reg (secure_vector< word > &reg)
 
std::string to_dec_string () const
 
std::string to_hex_string () const
 
uint32_t to_u32bit () const
 
size_t top_bits_free () const
 
word word_at (size_t n) const
 
 ~BigInt ()
 

Static Public Member Functions

static BigInt add2 (const BigInt &x, const word y[], size_t y_words, Sign y_sign)
 
static void const_time_lookup (secure_vector< word > &output, const std::vector< BigInt > &vec, size_t idx)
 
static BigInt decode (const uint8_t buf[], size_t length)
 
template<typename Alloc >
static BigInt decode (const std::vector< uint8_t, Alloc > &buf)
 
static BigInt decode (const uint8_t buf[], size_t length, Base base)
 
template<typename Alloc >
static BigInt decode (const std::vector< uint8_t, Alloc > &buf, Base base)
 
static std::vector< uint8_t > encode (const BigInt &n)
 
static void encode (uint8_t buf[], const BigInt &n)
 
static std::vector< uint8_t > encode (const BigInt &n, Base base)
 
static void encode (uint8_t buf[], const BigInt &n, Base base)
 
static secure_vector< uint8_t > encode_1363 (const BigInt &n, size_t bytes)
 
static void encode_1363 (uint8_t out[], size_t bytes, const BigInt &n)
 
static secure_vector< uint8_t > encode_fixed_length_int_pair (const BigInt &n1, const BigInt &n2, size_t bytes)
 
static secure_vector< uint8_t > encode_locked (const BigInt &n)
 
static secure_vector< uint8_t > encode_locked (const BigInt &n, Base base)
 
static BigInt power_of_2 (size_t n)
 
static BigInt random_integer (RandomNumberGenerator &rng, const BigInt &min, const BigInt &max)
 

Detailed Description

Arbitrary precision integer

Definition at line 24 of file bigint.h.

Member Enumeration Documentation

◆ Base

Base enumerator for encoding and decoding

Enumerator
Decimal 
Hexadecimal 
Binary 

Definition at line 30 of file bigint.h.

◆ Sign

Sign symbol definitions for positive and negative numbers

Enumerator
Negative 
Positive 

Definition at line 35 of file bigint.h.

Constructor & Destructor Documentation

◆ BigInt() [1/12]

Botan::BigInt::BigInt ( )
default

Create empty BigInt

◆ BigInt() [2/12]

Botan::BigInt::BigInt ( uint64_t  n)

Create BigInt from 64 bit integer

Parameters
ninitial value of this BigInt

Definition at line 25 of file bigint.cpp.

26  {
27  if(n > 0)
28  {
29 #if BOTAN_MP_WORD_BITS == 32
30  m_data.set_word_at(0, static_cast<word>(n));
31  m_data.set_word_at(1, static_cast<word>(n >> 32));
32 #else
33  m_data.set_word_at(0, n);
34 #endif
35  }
36 
37  }

◆ BigInt() [3/12]

Botan::BigInt::BigInt ( const BigInt other)
default

Copy Constructor

Parameters
otherthe BigInt to copy

◆ BigInt() [4/12]

Botan::BigInt::BigInt ( const std::string &  str)
explicit

Create BigInt from a string. If the string starts with 0x the rest of the string will be interpreted as hexadecimal digits. Otherwise, it will be interpreted as a decimal number.

Parameters
strthe string to parse for an integer value

Definition at line 51 of file bigint.cpp.

References Botan::cast_char_ptr_to_uint8(), Decimal, decode(), Hexadecimal, Negative, Positive, and set_sign().

52  {
53  Base base = Decimal;
54  size_t markers = 0;
55  bool negative = false;
56 
57  if(str.length() > 0 && str[0] == '-')
58  {
59  markers += 1;
60  negative = true;
61  }
62 
63  if(str.length() > markers + 2 && str[markers ] == '0' &&
64  str[markers + 1] == 'x')
65  {
66  markers += 2;
67  base = Hexadecimal;
68  }
69 
70  *this = decode(cast_char_ptr_to_uint8(str.data()) + markers,
71  str.length() - markers, base);
72 
73  if(negative) set_sign(Negative);
74  else set_sign(Positive);
75  }
const uint8_t * cast_char_ptr_to_uint8(const char *s)
Definition: mem_ops.h:190
static BigInt decode(const uint8_t buf[], size_t length)
Definition: bigint.h:805
void set_sign(Sign sign)
Definition: bigint.h:563

◆ BigInt() [5/12]

Botan::BigInt::BigInt ( const uint8_t  buf[],
size_t  length 
)

Create a BigInt from an integer in a byte array

Parameters
bufthe byte array holding the value
lengthsize of buf

Definition at line 77 of file bigint.cpp.

References binary_decode().

78  {
79  binary_decode(input, length);
80  }
void binary_decode(const uint8_t buf[], size_t length)
Definition: bigint.cpp:432

◆ BigInt() [6/12]

template<typename Alloc >
Botan::BigInt::BigInt ( const std::vector< uint8_t, Alloc > &  vec)
inlineexplicit

Create a BigInt from an integer in a byte array

Parameters
vecthe byte vector holding the value

Definition at line 87 of file bigint.h.

87 : BigInt(vec.data(), vec.size()) {}
BigInt()=default

◆ BigInt() [7/12]

Botan::BigInt::BigInt ( const uint8_t  buf[],
size_t  length,
Base  base 
)

Create a BigInt from an integer in a byte array

Parameters
bufthe byte array holding the value
lengthsize of buf
baseis the number base of the integer in buf

Definition at line 85 of file bigint.cpp.

References decode().

86  {
87  *this = decode(input, length, base);
88  }
static BigInt decode(const uint8_t buf[], size_t length)
Definition: bigint.h:805

◆ BigInt() [8/12]

Botan::BigInt::BigInt ( const uint8_t  buf[],
size_t  length,
size_t  max_bits 
)

Create a BigInt from an integer in a byte array

Parameters
bufthe byte array holding the value
lengthsize of buf
max_bitsif the resulting integer is more than max_bits, it will be shifted so it is at most max_bits in length.

Definition at line 90 of file bigint.cpp.

References binary_decode().

91  {
92  if(8 * length > max_bits)
93  length = (max_bits + 7) / 8;
94 
95  binary_decode(buf, length);
96 
97  if(8 * length > max_bits)
98  *this >>= (8 - (max_bits % 8));
99  }
void binary_decode(const uint8_t buf[], size_t length)
Definition: bigint.cpp:432

◆ BigInt() [9/12]

Botan::BigInt::BigInt ( const word  words[],
size_t  length 
)

Create a BigInt from an array of words

Parameters
wordsthe words
lengthnumber of words

Definition at line 17 of file bigint.cpp.

18  {
19  m_data.set_words(words, length);
20  }

◆ BigInt() [10/12]

Botan::BigInt::BigInt ( RandomNumberGenerator rng,
size_t  bits,
bool  set_high_bit = true 
)

Create a random BigInt of the specified size.

Parameters
rngrandom number generator
bitssize in bits
set_high_bitif true, the highest bit is always set
See also
randomize

Definition at line 104 of file bigint.cpp.

References bits(), and randomize().

105  {
106  randomize(rng, bits, set_high_bit);
107  }
size_t bits() const
Definition: bigint.cpp:296
void randomize(RandomNumberGenerator &rng, size_t bitsize, bool set_high_bit=true)
Definition: big_rand.cpp:17

◆ BigInt() [11/12]

Botan::BigInt::BigInt ( Sign  sign,
size_t  n 
)

Create BigInt of specified size, all zeros

Parameters
signthe sign
nsize of the internal register in words

Definition at line 42 of file bigint.cpp.

References size().

43  {
44  m_data.set_size(size);
45  m_signedness = s;
46  }
size_t size() const
Definition: bigint.h:580

◆ BigInt() [12/12]

Botan::BigInt::BigInt ( BigInt &&  other)
inline

Move constructor

Definition at line 134 of file bigint.h.

135  {
136  this->swap(other);
137  }
void swap(BigInt &other)
Definition: bigint.h:161

◆ ~BigInt()

Botan::BigInt::~BigInt ( )
inline

Definition at line 139 of file bigint.h.

139 { const_time_unpoison(); }
void const_time_unpoison() const
Definition: bigint.h:740

Member Function Documentation

◆ abs()

BigInt Botan::BigInt::abs ( ) const
Returns
absolute (positive) value of this

Definition at line 392 of file bigint.cpp.

References Positive, and set_sign().

Referenced by Botan::abs().

393  {
394  BigInt x = (*this);
395  x.set_sign(Positive);
396  return x;
397  }
BigInt()=default

◆ add()

BigInt & Botan::BigInt::add ( const word  y[],
size_t  y_words,
Sign  sign 
)

Definition at line 15 of file big_ops2.cpp.

References Botan::bigint_add2(), Botan::bigint_cmp(), Botan::bigint_sub2(), Botan::bigint_sub2_rev(), data(), grow_to(), mutable_data(), Positive, set_sign(), sig_words(), sign(), and size().

Referenced by Botan::Modular_Reducer::reduce().

16  {
17  const size_t x_sw = sig_words();
18 
19  grow_to(std::max(x_sw, y_words) + 1);
20 
21  if(sign() == y_sign)
22  {
23  bigint_add2(mutable_data(), size() - 1, y, y_words);
24  }
25  else
26  {
27  const int32_t relative_size = bigint_cmp(data(), x_sw, y, y_words);
28 
29  if(relative_size >= 0)
30  {
31  // *this >= y
32  bigint_sub2(mutable_data(), x_sw, y, y_words);
33  }
34  else
35  {
36  // *this < y
37  bigint_sub2_rev(mutable_data(), y, y_words);
38  }
39 
40  //this->sign_fixup(relative_size, y_sign);
41  if(relative_size < 0)
42  set_sign(y_sign);
43  else if(relative_size == 0)
45  }
46 
47  return (*this);
48  }
void bigint_sub2_rev(word x[], const word y[], size_t y_size)
Definition: mp_core.h:324
int32_t bigint_cmp(const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:525
word bigint_sub2(word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:300
Sign sign() const
Definition: bigint.h:539
word * mutable_data()
Definition: bigint.h:614
const word * data() const
Definition: bigint.h:620
size_t size() const
Definition: bigint.h:580
size_t sig_words() const
Definition: bigint.h:586
void grow_to(size_t n) const
Definition: bigint.h:636
void bigint_add2(word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:280
void set_sign(Sign sign)
Definition: bigint.h:563

◆ add2()

BigInt Botan::BigInt::add2 ( const BigInt x,
const word  y[],
size_t  y_words,
BigInt::Sign  y_sign 
)
static

Definition at line 18 of file big_ops3.cpp.

References Botan::bigint_add3(), Botan::bigint_sub_abs(), data(), Positive, sig_words(), and sign().

Referenced by Botan::operator+(), and Botan::operator-().

19  {
20  const size_t x_sw = x.sig_words();
21 
22  BigInt z(x.sign(), std::max(x_sw, y_words) + 1);
23 
24  if(x.sign() == y_sign)
25  {
26  bigint_add3(z.mutable_data(), x.data(), x_sw, y, y_words);
27  }
28  else
29  {
30  const int32_t relative_size = bigint_sub_abs(z.mutable_data(), x.data(), x_sw, y, y_words);
31 
32  //z.sign_fixup(relative_size, y_sign);
33  if(relative_size < 0)
34  z.set_sign(y_sign);
35  else if(relative_size == 0)
36  z.set_sign(BigInt::Positive);
37  }
38 
39  return z;
40  }
CT::Mask< word > bigint_sub_abs(word z[], const word x[], const word y[], size_t N, word ws[])
Definition: mp_core.h:377
BigInt()=default
void bigint_add3(word z[], const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:289

◆ binary_decode() [1/2]

void Botan::BigInt::binary_decode ( const uint8_t  buf[],
size_t  length 
)

Read integer value from a byte array with given size

Parameters
bufbyte array buffer containing the integer
lengthsize of buf

Definition at line 432 of file bigint.cpp.

References clear(), and Botan::round_up().

Referenced by BigInt(), botan_mp_from_bin(), decode(), Botan::generate_dsa_primes(), Botan::RFC6979_Nonce_Generator::nonce_for(), and randomize().

433  {
434  clear();
435 
436  const size_t full_words = length / sizeof(word);
437  const size_t extra_bytes = length % sizeof(word);
438 
439  secure_vector<word> reg((round_up(full_words + (extra_bytes > 0 ? 1 : 0), 8)));
440 
441  for(size_t i = 0; i != full_words; ++i)
442  {
443  reg[i] = load_be<word>(buf + length - sizeof(word)*(i+1), 0);
444  }
445 
446  if(extra_bytes > 0)
447  {
448  for(size_t i = 0; i != extra_bytes; ++i)
449  reg[full_words] = (reg[full_words] << 8) | buf[i];
450  }
451 
452  m_data.swap(reg);
453  }
void clear()
Definition: bigint.h:366
size_t round_up(size_t n, size_t align_to)
Definition: rounding.h:21

◆ binary_decode() [2/2]

template<typename Alloc >
void Botan::BigInt::binary_decode ( const std::vector< uint8_t, Alloc > &  buf)
inline

Read integer value from a byte vector

Parameters
bufthe vector to load from

Definition at line 692 of file bigint.h.

693  {
694  binary_decode(buf.data(), buf.size());
695  }
void binary_decode(const uint8_t buf[], size_t length)
Definition: bigint.cpp:432

◆ binary_encode() [1/2]

void Botan::BigInt::binary_encode ( uint8_t  buf[]) const

Store BigInt-value in a given byte array

Parameters
bufdestination byte array for the integer value

Definition at line 399 of file bigint.cpp.

References bytes().

Referenced by Botan::base58_decode(), botan_mp_to_bin(), Botan::DER_Encoder::encode(), encode(), encode_1363(), encode_fixed_length_int_pair(), encode_locked(), and Botan::GOST_3410_PublicKey::public_key_bits().

400  {
401  this->binary_encode(buf, bytes());
402  }
void binary_encode(uint8_t buf[]) const
Definition: bigint.cpp:399
size_t bytes() const
Definition: bigint.cpp:281

◆ binary_encode() [2/2]

void Botan::BigInt::binary_encode ( uint8_t  buf[],
size_t  len 
) const

Store BigInt-value in a given byte array. If len is less than the size of the value, then it will be truncated. If len is greater than the size of the value, it will be zero-padded. If len exactly equals this->bytes(), this function behaves identically to binary_encode.

Parameters
bufdestination byte array for the integer value
lenhow many bytes to write

Definition at line 407 of file bigint.cpp.

References Botan::get_byte(), Botan::store_be(), and word_at().

408  {
409  const size_t full_words = len / sizeof(word);
410  const size_t extra_bytes = len % sizeof(word);
411 
412  for(size_t i = 0; i != full_words; ++i)
413  {
414  const word w = word_at(i);
415  store_be(w, output + (len - (i+1)*sizeof(word)));
416  }
417 
418  if(extra_bytes > 0)
419  {
420  const word w = word_at(full_words);
421 
422  for(size_t i = 0; i != extra_bytes; ++i)
423  {
424  output[extra_bytes - i - 1] = get_byte(sizeof(word) - i - 1, w);
425  }
426  }
427  }
void store_be(uint16_t in, uint8_t out[2])
Definition: loadstor.h:438
constexpr uint8_t get_byte(size_t byte_num, T input)
Definition: loadstor.h:41
word word_at(size_t n) const
Definition: bigint.h:508

◆ bits()

size_t Botan::BigInt::bits ( ) const

Get the bit length of the integer

Returns
bit length of the represented integer value

Definition at line 296 of file bigint.cpp.

References sig_words(), and top_bits_free().

Referenced by BigInt(), botan_mp_num_bits(), bytes(), Botan::ct_divide(), Botan::ct_divide_u8(), Botan::ct_modulo(), Botan::BER_Decoder::decode(), Botan::BER_Decoder::decode_constrained_integer(), Botan::DL_Group::DL_Group(), Botan::DER_Encoder::encode(), encoded_size(), Botan::gcd(), Botan::generate_dsa_primes(), Botan::generate_rsa_prime(), Botan::generate_srp6_verifier(), Botan::inverse_mod(), Botan::is_lucas_probable_prime(), Botan::is_perfect_square(), Botan::is_prime(), Botan::TPM_PrivateKey::key_length(), Botan::monty_multi_exp(), Botan::PointGFp_Base_Point_Precompute::mul(), Botan::PointGFp_Var_Point_Precompute::mul(), Botan::PointGFp_Multi_Point_Precompute::multi_exp(), Botan::operator*(), operator/=(), Botan::passes_miller_rabin_test(), Botan::DL_Group::power_g_p(), Botan::power_mod(), random_integer(), Botan::random_prime(), Botan::RSA_PrivateKey::RSA_PrivateKey(), Botan::srp6_group_identifier(), to_hex_string(), and to_u32bit().

297  {
298  const size_t words = sig_words();
299 
300  if(words == 0)
301  return 0;
302 
303  const size_t full_words = (words - 1) * BOTAN_MP_WORD_BITS;
304  const size_t top_bits = BOTAN_MP_WORD_BITS - top_bits_free();
305 
306  return full_words + top_bits;
307  }
size_t sig_words() const
Definition: bigint.h:586
size_t top_bits_free() const
Definition: bigint.cpp:286

◆ byte_at()

uint8_t Botan::BigInt::byte_at ( size_t  n) const
Parameters
nthe offset to get a byte from
Returns
byte at offset n

Definition at line 109 of file bigint.cpp.

References Botan::get_byte(), and word_at().

Referenced by Botan::BER_Decoder::decode(), Botan::BER_Decoder::decode_constrained_integer(), and to_u32bit().

110  {
111  return get_byte(sizeof(word) - (n % sizeof(word)) - 1,
112  word_at(n / sizeof(word)));
113  }
constexpr uint8_t get_byte(size_t byte_num, T input)
Definition: loadstor.h:41
word word_at(size_t n) const
Definition: bigint.h:508

◆ bytes()

size_t Botan::BigInt::bytes ( ) const

Give byte length of the integer

Returns
byte length of the represented integer value

Definition at line 281 of file bigint.cpp.

References bits(), and Botan::round_up().

Referenced by Botan::base58_decode(), binary_encode(), botan_mp_num_bytes(), Botan::ECIES_KA_Operation::derive_secret(), Botan::DER_Encoder::encode(), Botan::PointGFp::encode(), encode(), encode_1363(), encode_fixed_length_int_pair(), encode_locked(), encoded_size(), Botan::EC_PrivateKey::private_key_bits(), Botan::GOST_3410_PublicKey::public_key_bits(), and Botan::SRP6_Server_Session::step1().

282  {
283  return round_up(bits(), 8) / 8;
284  }
size_t bits() const
Definition: bigint.cpp:296
size_t round_up(size_t n, size_t align_to)
Definition: rounding.h:21

◆ clear()

void Botan::BigInt::clear ( )
inline

Zeroize the BigInt. The size of the underlying register is not modified.

Definition at line 366 of file bigint.h.

Referenced by Botan::PointGFp::add(), Botan::PointGFp::add_affine(), binary_decode(), botan_mp_clear(), mul(), operator*=(), and randomize().

366 { m_data.set_to_zero(); m_signedness = Positive; }

◆ clear_bit()

void Botan::BigInt::clear_bit ( size_t  n)

Clear bit at specified position

Parameters
nbit position to clear

Definition at line 270 of file bigint.cpp.

References size(), and word_at().

Referenced by botan_mp_clear_bit().

271  {
272  const size_t which = n / BOTAN_MP_WORD_BITS;
273 
274  if(which < size())
275  {
276  const word mask = ~(static_cast<word>(1) << (n % BOTAN_MP_WORD_BITS));
277  m_data.set_word_at(which, word_at(which) & mask);
278  }
279  }
word word_at(size_t n) const
Definition: bigint.h:508
size_t size() const
Definition: bigint.h:580

◆ cmp()

int32_t Botan::BigInt::cmp ( const BigInt n,
bool  check_signs = true 
) const

Compare this to another BigInt

Parameters
nthe BigInt value to compare with
check_signsinclude sign in comparison?
Returns
if (this<n) return -1, if (this>n) return 1, if both values are identical return 0 [like Perl's <=> operator]

Definition at line 130 of file bigint.cpp.

References Botan::bigint_cmp(), data(), is_negative(), is_positive(), and size().

Referenced by botan_mp_cmp(), Botan::operator<=(), and Botan::operator>=().

131  {
132  if(check_signs)
133  {
134  if(other.is_positive() && this->is_negative())
135  return -1;
136 
137  if(other.is_negative() && this->is_positive())
138  return 1;
139 
140  if(other.is_negative() && this->is_negative())
141  return (-bigint_cmp(this->data(), this->size(),
142  other.data(), other.size()));
143  }
144 
145  return bigint_cmp(this->data(), this->size(),
146  other.data(), other.size());
147  }
bool is_negative() const
Definition: bigint.h:527
int32_t bigint_cmp(const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:525
const word * data() const
Definition: bigint.h:620
size_t size() const
Definition: bigint.h:580
bool is_positive() const
Definition: bigint.h:533

◆ cmp_word()

int32_t Botan::BigInt::cmp_word ( word  n) const

Compare this to an integer

Parameters
nthe value to compare with
Returns
if (this<n) return -1, if (this>n) return 1, if both values are identical return 0 [like Perl's <=> operator]

Definition at line 115 of file bigint.cpp.

References Botan::bigint_cmp(), data(), is_negative(), and sig_words().

Referenced by Botan::operator!=(), Botan::operator<(), Botan::operator<=(), Botan::operator==(), Botan::operator>(), and Botan::operator>=().

116  {
117  if(is_negative())
118  return -1; // other is positive ...
119 
120  const size_t sw = this->sig_words();
121  if(sw > 1)
122  return 1; // must be larger since other is just one word ...
123 
124  return bigint_cmp(this->data(), sw, &other, 1);
125  }
bool is_negative() const
Definition: bigint.h:527
int32_t bigint_cmp(const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:525
const word * data() const
Definition: bigint.h:620
size_t sig_words() const
Definition: bigint.h:586

◆ cond_flip_sign()

void Botan::BigInt::cond_flip_sign ( bool  predicate)

If predicate is true flip the sign of *this

Definition at line 475 of file bigint.cpp.

References Botan::CT::Mask< T >::expand(), set_sign(), and sign().

Referenced by ct_cond_assign(), and rev_sub().

476  {
477  // This code is assuming Negative == 0, Positive == 1
478 
479  const auto mask = CT::Mask<uint8_t>::expand(predicate);
480 
481  const uint8_t current_sign = static_cast<uint8_t>(sign());
482 
483  const uint8_t new_sign = mask.select(current_sign ^ 1, current_sign);
484 
485  set_sign(static_cast<Sign>(new_sign));
486  }
Sign sign() const
Definition: bigint.h:539
static Mask< T > expand(T v)
Definition: ct_utils.h:123
void set_sign(Sign sign)
Definition: bigint.h:563

◆ conditionally_set_bit()

void Botan::BigInt::conditionally_set_bit ( size_t  n,
bool  set_it 
)

Conditionally set bit at specified position. Note if set_it is false, nothing happens, and if the bit is already set, it remains set.

Parameters
nbit position to set
set_itif the bit should be set

Definition at line 260 of file bigint.cpp.

References word_at().

Referenced by Botan::ct_divide(), Botan::ct_divide_u8(), and Botan::ct_modulo().

261  {
262  const size_t which = n / BOTAN_MP_WORD_BITS;
263  const word mask = static_cast<word>(set_it) << (n % BOTAN_MP_WORD_BITS);
264  m_data.set_word_at(which, word_at(which) | mask);
265  }
word word_at(size_t n) const
Definition: bigint.h:508

◆ const_time_lookup()

void Botan::BigInt::const_time_lookup ( secure_vector< word > &  output,
const std::vector< BigInt > &  vec,
size_t  idx 
)
static

Set output = vec[idx].m_reg in constant time

All elements of vec must have the same size, and output must be pre-allocated with the same size.

Definition at line 523 of file bigint.cpp.

References BOTAN_ASSERT, Botan::clear_mem(), Botan::CT::Mask< T >::is_equal(), Botan::CT::poison(), size(), and Botan::CT::unpoison().

526  {
527  const size_t words = output.size();
528 
529  clear_mem(output.data(), output.size());
530 
531  CT::poison(&idx, sizeof(idx));
532 
533  for(size_t i = 0; i != vec.size(); ++i)
534  {
535  BOTAN_ASSERT(vec[i].size() >= words,
536  "Word size as expected in const_time_lookup");
537 
538  const auto mask = CT::Mask<word>::is_equal(i, idx);
539 
540  for(size_t w = 0; w != words; ++w)
541  {
542  const word viw = vec[i].word_at(w);
543  output[w] = mask.if_set_return(viw);
544  }
545  }
546 
547  CT::unpoison(idx);
548  CT::unpoison(output.data(), output.size());
549  }
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:115
void poison(const T *p, size_t n)
Definition: ct_utils.h:48
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:55
size_t size() const
Definition: bigint.h:580
void unpoison(const T *p, size_t n)
Definition: ct_utils.h:59
static Mask< T > is_equal(T x, T y)
Definition: ct_utils.h:149

◆ const_time_poison()

void Botan::BigInt::const_time_poison ( ) const
inline

Definition at line 739 of file bigint.h.

Referenced by Botan::gcd().

739 {}

◆ const_time_unpoison()

void Botan::BigInt::const_time_unpoison ( ) const
inline

Definition at line 740 of file bigint.h.

Referenced by Botan::gcd().

740 {}

◆ ct_cond_add()

void Botan::BigInt::ct_cond_add ( bool  predicate,
const BigInt value 
)

If predicate is true add value to *this

Definition at line 455 of file bigint.cpp.

References Botan::bigint_cnd_add(), data(), grow_to(), is_negative(), mutable_data(), sig_words(), and size().

Referenced by Botan::gcd(), and Botan::is_lucas_probable_prime().

456  {
457  if(this->is_negative() || value.is_negative())
458  throw Invalid_Argument("BigInt::ct_cond_add requires both values to be positive");
459  this->grow_to(1 + value.sig_words());
460 
461  bigint_cnd_add(static_cast<word>(predicate),
462  this->mutable_data(), this->size(),
463  value.data(), value.sig_words());
464  }
bool is_negative() const
Definition: bigint.h:527
word * mutable_data()
Definition: bigint.h:614
word bigint_cnd_add(word cnd, word x[], word x_size, const word y[], size_t y_size)
Definition: mp_core.h:42
size_t size() const
Definition: bigint.h:580
void grow_to(size_t n) const
Definition: bigint.h:636

◆ ct_cond_assign()

void Botan::BigInt::ct_cond_assign ( bool  predicate,
const BigInt other 
)

If predicate is true assign other to *this Uses a masked operation to avoid side channels

Definition at line 488 of file bigint.cpp.

References cond_flip_sign(), Botan::CT::Mask< T >::expand(), grow_to(), set_word_at(), sign(), size(), and word_at().

Referenced by Botan::inverse_mod(), Botan::is_lucas_probable_prime(), and Botan::power_mod().

489  {
490  const size_t t_words = size();
491  const size_t o_words = other.size();
492 
493  if(o_words < t_words)
494  grow_to(o_words);
495 
496  const size_t r_words = std::max(t_words, o_words);
497 
498  const auto mask = CT::Mask<word>::expand(predicate);
499 
500  for(size_t i = 0; i != r_words; ++i)
501  {
502  const word o_word = other.word_at(i);
503  const word t_word = this->word_at(i);
504  this->set_word_at(i, mask.select(o_word, t_word));
505  }
506 
507  const bool different_sign = sign() != other.sign();
508  cond_flip_sign(predicate && different_sign);
509  }
Sign sign() const
Definition: bigint.h:539
word word_at(size_t n) const
Definition: bigint.h:508
static Mask< T > expand(T v)
Definition: ct_utils.h:123
size_t size() const
Definition: bigint.h:580
void cond_flip_sign(bool predicate)
Definition: bigint.cpp:475
void grow_to(size_t n) const
Definition: bigint.h:636
void set_word_at(size_t i, word w)
Definition: bigint.h:513

◆ ct_cond_swap()

void Botan::BigInt::ct_cond_swap ( bool  predicate,
BigInt other 
)

If predicate is true swap *this and other Uses a masked operation to avoid side channels

Definition at line 466 of file bigint.cpp.

References Botan::bigint_cnd_swap(), grow_to(), mutable_data(), and size().

Referenced by Botan::ct_divide(), Botan::ct_modulo(), and Botan::gcd().

467  {
468  const size_t max_words = std::max(size(), other.size());
469  grow_to(max_words);
470  other.grow_to(max_words);
471 
472  bigint_cnd_swap(predicate, this->mutable_data(), other.mutable_data(), max_words);
473  }
word * mutable_data()
Definition: bigint.h:614
void bigint_cnd_swap(word cnd, word x[], word y[], size_t size)
Definition: mp_core.h:29
size_t size() const
Definition: bigint.h:580
void grow_to(size_t n) const
Definition: bigint.h:636

◆ ct_reduce_below()

void Botan::BigInt::ct_reduce_below ( const BigInt mod,
secure_vector< word > &  ws,
size_t  bound 
)

Return *this % mod

Assumes that *this is (if anything) only slightly larger than mod and performs repeated subtractions. It should not be used if *this is much larger than mod, instead use modulo operator.

Performs exactly bound subtractions, so if *this is >= bound*mod then the result will not be fully reduced. If bound is zero, nothing happens.

Definition at line 366 of file bigint.cpp.

References Botan::bigint_sub3(), Botan::clear_mem(), data(), grow_to(), is_negative(), Botan::CT::Mask< T >::is_zero(), mutable_data(), sig_words(), and size().

Referenced by Botan::Modular_Reducer::reduce().

367  {
368  if(mod.is_negative() || this->is_negative())
369  throw Invalid_Argument("BigInt::ct_reduce_below both values must be positive");
370 
371  const size_t mod_words = mod.sig_words();
372 
373  grow_to(mod_words);
374 
375  const size_t sz = size();
376 
377  ws.resize(sz);
378 
379  clear_mem(ws.data(), sz);
380 
381  for(size_t i = 0; i != bound; ++i)
382  {
383  word borrow = bigint_sub3(ws.data(), data(), sz, mod.data(), mod_words);
384 
385  CT::Mask<word>::is_zero(borrow).select_n(mutable_data(), ws.data(), data(), sz);
386  }
387  }
bool is_negative() const
Definition: bigint.h:527
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:115
word * mutable_data()
Definition: bigint.h:614
word bigint_sub3(word z[], const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:342
const word * data() const
Definition: bigint.h:620
size_t size() const
Definition: bigint.h:580
void grow_to(size_t n) const
Definition: bigint.h:636
static Mask< T > is_zero(T x)
Definition: ct_utils.h:141

◆ data()

const word* Botan::BigInt::data ( ) const
inline

◆ decode() [1/4]

static BigInt Botan::BigInt::decode ( const uint8_t  buf[],
size_t  length 
)
inlinestatic

Create a BigInt from an integer in a byte array

Parameters
bufthe binary value to load
lengthsize of buf
Returns
BigInt representing the integer in the byte array

Definition at line 805 of file bigint.h.

Referenced by BigInt(), Botan::TLS::Client_Key_Exchange::Client_Key_Exchange(), decode(), Botan::BER_Decoder::decode_octet_string_bigint(), Botan::CRL_Entry::encode_into(), Botan::TPM_PrivateKey::get_e(), Botan::TPM_PrivateKey::get_n(), Botan::OCSP::CertID::is_id_for(), Botan::OS2ECP(), and Botan::TLS::Callbacks::tls_dh_agree().

806  {
807  return BigInt(buf, length);
808  }
BigInt()=default

◆ decode() [2/4]

template<typename Alloc >
static BigInt Botan::BigInt::decode ( const std::vector< uint8_t, Alloc > &  buf)
inlinestatic

Create a BigInt from an integer in a byte array

Parameters
bufthe binary value to load
Returns
BigInt representing the integer in the byte array

Definition at line 816 of file bigint.h.

817  {
818  return BigInt(buf);
819  }
BigInt()=default

◆ decode() [3/4]

BigInt Botan::BigInt::decode ( const uint8_t  buf[],
size_t  length,
Base  base 
)
static

Create a BigInt from an integer in a byte array

Parameters
bufthe binary value to load
lengthsize of buf
basenumber-base of the integer in buf
Returns
BigInt representing the integer in the byte array

Definition at line 146 of file big_code.cpp.

References Binary, binary_decode(), Botan::cast_uint8_ptr_to_char(), Botan::Charset::char2digit(), Decimal, Botan::hex_decode_locked(), Hexadecimal, Botan::Charset::is_digit(), and Botan::Charset::is_space().

147  {
148  BigInt r;
149  if(base == Binary)
150  {
151  r.binary_decode(buf, length);
152  }
153  else if(base == Hexadecimal)
154  {
155  secure_vector<uint8_t> binary;
156 
157  if(length % 2)
158  {
159  // Handle lack of leading 0
160  const char buf0_with_leading_0[2] =
161  { '0', static_cast<char>(buf[0]) };
162 
163  binary = hex_decode_locked(buf0_with_leading_0, 2);
164 
165  binary += hex_decode_locked(cast_uint8_ptr_to_char(&buf[1]),
166  length - 1,
167  false);
168  }
169  else
171  length, false);
172 
173  r.binary_decode(binary.data(), binary.size());
174  }
175  else if(base == Decimal)
176  {
177  for(size_t i = 0; i != length; ++i)
178  {
179  if(Charset::is_space(buf[i]))
180  continue;
181 
182  if(!Charset::is_digit(buf[i]))
183  throw Invalid_Argument("BigInt::decode: "
184  "Invalid character in decimal input");
185 
186  const uint8_t x = Charset::char2digit(buf[i]);
187 
188  if(x >= 10)
189  throw Invalid_Argument("BigInt: Invalid decimal string");
190 
191  r *= 10;
192  r += x;
193  }
194  }
195  else
196  throw Invalid_Argument("Unknown BigInt decoding method");
197  return r;
198  }
secure_vector< uint8_t > hex_decode_locked(const char input[], size_t input_length, bool ignore_ws)
Definition: hex.cpp:168
uint8_t char2digit(char c)
Definition: charset.cpp:231
bool is_space(char c)
Definition: charset.cpp:221
const char * cast_uint8_ptr_to_char(const uint8_t *b)
Definition: mem_ops.h:195
bool is_digit(char c)
Definition: charset.cpp:210
BigInt()=default

◆ decode() [4/4]

template<typename Alloc >
static BigInt Botan::BigInt::decode ( const std::vector< uint8_t, Alloc > &  buf,
Base  base 
)
inlinestatic

Create a BigInt from an integer in a byte array

Parameters
bufthe binary value to load
basenumber-base of the integer in buf
Returns
BigInt representing the integer in the byte array

Definition at line 878 of file bigint.h.

References decode().

879  {
880  if(base == Binary)
881  return BigInt(buf);
882  return BigInt::decode(buf.data(), buf.size(), base);
883  }
static BigInt decode(const uint8_t buf[], size_t length)
Definition: bigint.h:805
BigInt()=default

◆ encode() [1/4]

static std::vector<uint8_t> Botan::BigInt::encode ( const BigInt n)
inlinestatic

Encode the integer value from a BigInt to a std::vector of bytes

Parameters
nthe BigInt to use as integer source
Returns
secure_vector of bytes containing the bytes of the integer

Definition at line 770 of file bigint.h.

References binary_encode(), and bytes().

Referenced by Botan::TLS::Client_Key_Exchange::Client_Key_Exchange(), Botan::CRL_Entry::decode_from(), Botan::ECIES_KA_Operation::derive_secret(), encode(), Botan::FPE_FE1::FPE_FE1(), Botan::TLS::Server_Key_Exchange::Server_Key_Exchange(), and to_hex_string().

771  {
772  std::vector<uint8_t> output(n.bytes());
773  n.binary_encode(output.data());
774  return output;
775  }

◆ encode() [2/4]

static void Botan::BigInt::encode ( uint8_t  buf[],
const BigInt n 
)
inlinestatic

Encode the integer value from a BigInt to a byte array

Parameters
bufdestination byte array for the encoded integer
nthe BigInt to use as integer source

Definition at line 794 of file bigint.h.

795  {
796  n.binary_encode(buf);
797  }

◆ encode() [3/4]

std::vector< uint8_t > Botan::BigInt::encode ( const BigInt n,
Base  base 
)
static

Encode the integer value from a BigInt to a std::vector of bytes

Parameters
nthe BigInt to use as integer source
basenumber-base of resulting byte array representation
Returns
secure_vector of bytes containing the integer with given base

Deprecated. If you need Binary, call the version of encode that doesn't take a Base. If you need Hex or Decimal output, use to_hex_string or to_dec_string resp.

Definition at line 81 of file big_code.cpp.

References Binary, Decimal, encode(), Hexadecimal, to_dec_string(), and to_hex_string().

82  {
83  if(base == Binary)
84  return BigInt::encode(n);
85  else if(base == Hexadecimal)
86  return str_to_vector(n.to_hex_string());
87  else if(base == Decimal)
88  return str_to_vector(n.to_dec_string());
89  else
90  throw Invalid_Argument("Unknown BigInt encoding base");
91  }
static std::vector< uint8_t > encode(const BigInt &n)
Definition: bigint.h:770

◆ encode() [4/4]

void Botan::BigInt::encode ( uint8_t  buf[],
const BigInt n,
Base  base 
)
static

Encode the integer value from a BigInt to a byte array

Parameters
bufdestination byte array for the encoded integer value with given base
nthe BigInt to use as integer source
basenumber-base of resulting byte array representation

Deprecated. If you need Binary, call binary_encode. If you need Hex or Decimal output, use to_hex_string or to_dec_string resp.

Definition at line 54 of file big_code.cpp.

References Botan::copy_mem(), and encode_locked().

55  {
56  secure_vector<uint8_t> enc = n.encode_locked(base);
57  copy_mem(output, enc.data(), enc.size());
58  }
void copy_mem(T *out, const T *in, size_t n)
Definition: mem_ops.h:133

◆ encode_1363() [1/2]

secure_vector< uint8_t > Botan::BigInt::encode_1363 ( const BigInt n,
size_t  bytes 
)
static

Encode a BigInt to a byte array according to IEEE 1363

Parameters
nthe BigInt to encode
bytesthe length of the resulting secure_vector<uint8_t>
Returns
a secure_vector<uint8_t> containing the encoded BigInt

Definition at line 111 of file big_code.cpp.

References binary_encode(), and bytes().

Referenced by Botan::PK_Verifier::check_signature(), Botan::EC_Group::DER_encode(), Botan::PointGFp::encode(), Botan::RFC6979_Nonce_Generator::nonce_for(), Botan::EC_PrivateKey::private_key_bits(), Botan::DH_PublicKey::public_value(), Botan::RFC6979_Nonce_Generator::RFC6979_Nonce_Generator(), Botan::Montgomery_Int::serialize(), Botan::sm2_compute_za(), Botan::srp6_client_agree(), and Botan::SRP6_Server_Session::step2().

112  {
113  if(n.bytes() > bytes)
114  throw Encoding_Error("encode_1363: n is too large to encode properly");
115 
116  secure_vector<uint8_t> output(bytes);
117  n.binary_encode(output.data(), output.size());
118  return output;
119  }
size_t bytes() const
Definition: bigint.cpp:281

◆ encode_1363() [2/2]

void Botan::BigInt::encode_1363 ( uint8_t  out[],
size_t  bytes,
const BigInt n 
)
static

Definition at line 122 of file big_code.cpp.

References binary_encode(), and bytes().

123  {
124  if(n.bytes() > bytes)
125  throw Encoding_Error("encode_1363: n is too large to encode properly");
126 
127  n.binary_encode(output, bytes);
128  }
size_t bytes() const
Definition: bigint.cpp:281

◆ encode_fixed_length_int_pair()

secure_vector< uint8_t > Botan::BigInt::encode_fixed_length_int_pair ( const BigInt n1,
const BigInt n2,
size_t  bytes 
)
static

Encode two BigInt to a byte array according to IEEE 1363

Parameters
n1the first BigInt to encode
n2the second BigInt to encode
bytesthe length of the encoding of each single BigInt
Returns
a secure_vector<uint8_t> containing the concatenation of the two encoded BigInt

Definition at line 133 of file big_code.cpp.

References binary_encode(), and bytes().

134  {
135  if(n1.bytes() > bytes || n2.bytes() > bytes)
136  throw Encoding_Error("encode_fixed_length_int_pair: values too large to encode properly");
137  secure_vector<uint8_t> output(2 * bytes);
138  n1.binary_encode(output.data() , bytes);
139  n2.binary_encode(output.data() + bytes, bytes);
140  return output;
141  }
size_t bytes() const
Definition: bigint.cpp:281

◆ encode_locked() [1/2]

static secure_vector<uint8_t> Botan::BigInt::encode_locked ( const BigInt n)
inlinestatic

Encode the integer value from a BigInt to a secure_vector of bytes

Parameters
nthe BigInt to use as integer source
Returns
secure_vector of bytes containing the bytes of the integer

Definition at line 782 of file bigint.h.

References binary_encode(), and bytes().

Referenced by encode(), and encode_locked().

783  {
784  secure_vector<uint8_t> output(n.bytes());
785  n.binary_encode(output.data());
786  return output;
787  }

◆ encode_locked() [2/2]

secure_vector< uint8_t > Botan::BigInt::encode_locked ( const BigInt n,
Base  base 
)
static

Encode the integer value from a BigInt to a secure_vector of bytes

Parameters
nthe BigInt to use as integer source
basenumber-base of resulting byte array representation
Returns
secure_vector of bytes containing the integer with given base

Deprecated. If you need Binary, call the version of encode_locked that doesn't take a Base. If you need Hex or Decimal output, use to_hex_string or to_dec_string resp.

Definition at line 96 of file big_code.cpp.

References Binary, Decimal, encode_locked(), Hexadecimal, to_dec_string(), and to_hex_string().

97  {
98  if(base == Binary)
99  return BigInt::encode_locked(n);
100  else if(base == Hexadecimal)
101  return str_to_lvector(n.to_hex_string());
102  else if(base == Decimal)
103  return str_to_lvector(n.to_dec_string());
104  else
105  throw Invalid_Argument("Unknown BigInt encoding base");
106  }
static secure_vector< uint8_t > encode_locked(const BigInt &n)
Definition: bigint.h:782

◆ encode_words()

void Botan::BigInt::encode_words ( word  out[],
size_t  size 
) const

Place the value into out, zero-padding up to size words Throw if *this cannot be represented in size words

Definition at line 176 of file bigint.cpp.

References Botan::clear_mem(), Botan::copy_mem(), data(), sig_words(), and size().

177  {
178  const size_t words = sig_words();
179 
180  if(words > size)
181  throw Encoding_Error("BigInt::encode_words value too large to encode");
182 
183  clear_mem(out, size);
184  copy_mem(out, data(), words);
185  }
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:115
const word * data() const
Definition: bigint.h:620
size_t size() const
Definition: bigint.h:580
void copy_mem(T *out, const T *in, size_t n)
Definition: mem_ops.h:133
size_t sig_words() const
Definition: bigint.h:586

◆ encoded_size()

size_t Botan::BigInt::encoded_size ( Base  base = Binary) const
Parameters
basethe base to measure the size for
Returns
size of this integer in base base

Deprecated. This is only needed when using the encode and encode_locked functions, which are also deprecated.

Definition at line 312 of file bigint.cpp.

References Binary, bits(), bytes(), Decimal, and Hexadecimal.

313  {
314  static const double LOG_2_BASE_10 = 0.30102999566;
315 
316  if(base == Binary)
317  return bytes();
318  else if(base == Hexadecimal)
319  return 2*bytes();
320  else if(base == Decimal)
321  return static_cast<size_t>((bits() * LOG_2_BASE_10) + 1);
322  else
323  throw Invalid_Argument("Unknown base for BigInt encoding");
324  }
size_t bits() const
Definition: bigint.cpp:296
size_t bytes() const
Definition: bigint.cpp:281

◆ flip_sign()

void Botan::BigInt::flip_sign ( )
inline

Flip the sign of this BigInt

Definition at line 554 of file bigint.h.

Referenced by botan_mp_flip_sign(), Botan::ct_divide_u8(), Botan::BER_Decoder::decode(), Botan::is_lucas_probable_prime(), and operator-().

555  {
557  }
Sign reverse_sign() const
Definition: bigint.h:544
void set_sign(Sign sign)
Definition: bigint.h:563

◆ get_bit()

bool Botan::BigInt::get_bit ( size_t  n) const
inline

Return bit value at specified position

Parameters
nthe bit offset to test
Returns
true, if the bit at position n is set, false otherwise

Definition at line 465 of file bigint.h.

Referenced by Botan::ct_divide(), Botan::ct_divide_u8(), Botan::ct_modulo(), Botan::PointGFp::encode(), Botan::is_lucas_probable_prime(), Botan::operator*(), and Botan::power_mod().

466  {
467  return ((word_at(n / BOTAN_MP_WORD_BITS) >> (n % BOTAN_MP_WORD_BITS)) & 1);
468  }
word word_at(size_t n) const
Definition: bigint.h:508

◆ get_substring()

uint32_t Botan::BigInt::get_substring ( size_t  offset,
size_t  length 
) const

Return (a maximum of) 32 bits of the complete value

Parameters
offsetthe offset to start extracting
lengthamount of bits to extract (starting at offset)
Returns
the integer extracted from the register starting at offset with specified length

Definition at line 213 of file bigint.cpp.

References word_at().

Referenced by Botan::monty_multi_exp(), Botan::PointGFp_Base_Point_Precompute::mul(), Botan::PointGFp_Var_Point_Precompute::mul(), and Botan::PointGFp_Multi_Point_Precompute::multi_exp().

214  {
215  if(length == 0 || length > 32)
216  throw Invalid_Argument("BigInt::get_substring invalid substring length");
217 
218  const uint32_t mask = 0xFFFFFFFF >> (32 - length);
219 
220  const size_t word_offset = offset / BOTAN_MP_WORD_BITS;
221  const size_t wshift = (offset % BOTAN_MP_WORD_BITS);
222 
223  /*
224  * The substring is contained within one or at most two words. The
225  * offset and length are not secret, so we can perform conditional
226  * operations on those values.
227  */
228  const word w0 = word_at(word_offset);
229 
230  if(wshift == 0 || (offset + length) / BOTAN_MP_WORD_BITS == word_offset)
231  {
232  return static_cast<uint32_t>(w0 >> wshift) & mask;
233  }
234  else
235  {
236  const word w1 = word_at(word_offset + 1);
237  return static_cast<uint32_t>((w0 >> wshift) | (w1 << (BOTAN_MP_WORD_BITS - wshift))) & mask;
238  }
239  }
word word_at(size_t n) const
Definition: bigint.h:508

◆ get_word_vector() [1/2]

secure_vector<word>& Botan::BigInt::get_word_vector ( )
inline

Don't use this function in application code

Definition at line 625 of file bigint.h.

Referenced by Botan::PointGFp::add_affine().

625 { return m_data.mutable_vector(); }

◆ get_word_vector() [2/2]

const secure_vector<word>& Botan::BigInt::get_word_vector ( ) const
inline

Don't use this function in application code

Definition at line 630 of file bigint.h.

630 { return m_data.const_vector(); }

◆ grow_to()

void Botan::BigInt::grow_to ( size_t  n) const
inline

◆ is_equal()

bool Botan::BigInt::is_equal ( const BigInt n) const

Compare this to another BigInt

Parameters
nthe BigInt value to compare with
Returns
true if this == n or false otherwise

Definition at line 149 of file bigint.cpp.

References Botan::bigint_ct_is_eq(), data(), sig_words(), and sign().

Referenced by Botan::operator!=().

150  {
151  if(this->sign() != other.sign())
152  return false;
153 
154  return bigint_ct_is_eq(this->data(), this->sig_words(),
155  other.data(), other.sig_words()).is_set();
156  }
Sign sign() const
Definition: bigint.h:539
const word * data() const
Definition: bigint.h:620
CT::Mask< word > bigint_ct_is_eq(const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:613
size_t sig_words() const
Definition: bigint.h:586

◆ is_even()

bool Botan::BigInt::is_even ( ) const
inline

Test if the integer has an even value

Returns
true if the integer is even, false otherwise

Definition at line 403 of file bigint.h.

Referenced by Botan::almost_montgomery_inverse(), botan_mp_is_even(), Botan::gcd(), Botan::generate_rsa_prime(), Botan::inverse_mod(), Botan::is_lucas_probable_prime(), Botan::is_prime(), Botan::jacobi(), Botan::Montgomery_Params::Montgomery_Params(), Botan::random_prime(), and Botan::ressol().

403 { return (get_bit(0) == 0); }
bool get_bit(size_t n) const
Definition: bigint.h:465

◆ is_less_than()

bool Botan::BigInt::is_less_than ( const BigInt n) const

Compare this to another BigInt

Parameters
nthe BigInt value to compare with
Returns
true if this < n or false otherwise

Definition at line 158 of file bigint.cpp.

References Botan::bigint_ct_is_lt(), data(), is_negative(), is_positive(), and sig_words().

Referenced by Botan::operator<(), and Botan::operator>().

159  {
160  if(this->is_negative() && other.is_positive())
161  return true;
162 
163  if(this->is_positive() && other.is_negative())
164  return false;
165 
166  if(other.is_negative() && this->is_negative())
167  {
168  return bigint_ct_is_lt(other.data(), other.sig_words(),
169  this->data(), this->sig_words()).is_set();
170  }
171 
172  return bigint_ct_is_lt(this->data(), this->sig_words(),
173  other.data(), other.sig_words()).is_set();
174  }
bool is_negative() const
Definition: bigint.h:527
const word * data() const
Definition: bigint.h:620
size_t sig_words() const
Definition: bigint.h:586
CT::Mask< word > bigint_ct_is_lt(const word x[], size_t x_size, const word y[], size_t y_size, bool lt_or_equal=false)
Definition: mp_core.h:576
bool is_positive() const
Definition: bigint.h:533

◆ is_negative()

bool Botan::BigInt::is_negative ( ) const
inline

◆ is_nonzero()

bool Botan::BigInt::is_nonzero ( ) const
inline

Test if the integer is not zero

Returns
true if the integer is non-zero, false otherwise

Definition at line 415 of file bigint.h.

Referenced by Botan::ct_modulo(), Botan::inverse_mod(), and Botan::Modular_Reducer::reduce().

415 { return (!is_zero()); }
bool is_zero() const
Definition: bigint.h:421

◆ is_odd()

bool Botan::BigInt::is_odd ( ) const
inline

Test if the integer has an odd value

Returns
true if the integer is odd, false otherwise

Definition at line 409 of file bigint.h.

Referenced by botan_mp_is_odd(), Botan::gcd(), Botan::inverse_mod(), Botan::is_lucas_probable_prime(), Botan::normalized_montgomery_inverse(), Botan::power_mod(), and Botan::Power_Mod::set_modulus().

409 { return (get_bit(0) == 1); }
bool get_bit(size_t n) const
Definition: bigint.h:465

◆ is_positive()

bool Botan::BigInt::is_positive ( ) const
inline

Tests if the sign of the integer is positive

Returns
true, iff the integer has a positive sign

Definition at line 533 of file bigint.h.

Referenced by botan_mp_is_positive(), cmp(), is_less_than(), and Botan::operator%().

533 { return (sign() == Positive); }
Sign sign() const
Definition: bigint.h:539

◆ is_zero()

bool Botan::BigInt::is_zero ( ) const
inline

◆ mask_bits()

void Botan::BigInt::mask_bits ( size_t  n)
inline

Clear all but the lowest n bits

Parameters
namount of bits to keep

Definition at line 455 of file bigint.h.

Referenced by Botan::inverse_mod(), Botan::redc_p192(), Botan::redc_p224(), Botan::redc_p256(), Botan::redc_p384(), Botan::redc_p521(), and Botan::Modular_Reducer::reduce().

456  {
457  m_data.mask_bits(n);
458  }

◆ mod_add()

BigInt & Botan::BigInt::mod_add ( const BigInt y,
const BigInt mod,
secure_vector< word > &  ws 
)

Set *this to (*this + y) % mod This function assumes *this is >= 0 && < mod

Parameters
ythe BigInt to add - assumed y >= 0 and y < mod
modthe positive modulus
wsa temp workspace

Definition at line 50 of file big_ops2.cpp.

References Botan::bigint_add3_nc(), Botan::bigint_sub3(), BOTAN_ARG_CHECK, BOTAN_DEBUG_ASSERT, Botan::CT::conditional_copy_mem(), data(), grow_to(), is_negative(), set_words(), and sig_words().

Referenced by Botan::Montgomery_Int::add(), Botan::PointGFp::mult2(), and Botan::Montgomery_Int::operator+().

51  {
52  if(this->is_negative() || s.is_negative() || mod.is_negative())
53  throw Invalid_Argument("BigInt::mod_add expects all arguments are positive");
54 
55  BOTAN_DEBUG_ASSERT(*this < mod);
56  BOTAN_DEBUG_ASSERT(s < mod);
57 
58  /*
59  t + s or t + s - p == t - (p - s)
60 
61  So first compute ws = p - s
62 
63  Then compute t + s and t - ws
64 
65  If t - ws does not borrow, then that is the correct valued
66  */
67 
68  const size_t mod_sw = mod.sig_words();
69  BOTAN_ARG_CHECK(mod_sw > 0, "BigInt::mod_add modulus must be positive");
70 
71  this->grow_to(mod_sw);
72  s.grow_to(mod_sw);
73 
74  // First mod_sw for p - s, 2*mod_sw for bigint_addsub workspace
75  if(ws.size() < 3*mod_sw)
76  ws.resize(3*mod_sw);
77 
78  word borrow = bigint_sub3(&ws[0], mod.data(), mod_sw, s.data(), mod_sw);
79  BOTAN_DEBUG_ASSERT(borrow == 0);
80 
81  // Compute t - ws
82  borrow = bigint_sub3(&ws[mod_sw], this->data(), mod_sw, &ws[0], mod_sw);
83 
84  // Compute t + s
85  bigint_add3_nc(&ws[mod_sw*2], this->data(), mod_sw, s.data(), mod_sw);
86 
87  CT::conditional_copy_mem(borrow, &ws[0], &ws[mod_sw*2], &ws[mod_sw], mod_sw);
88  set_words(&ws[0], mod_sw);
89 
90  return (*this);
91  }
bool is_negative() const
Definition: bigint.h:527
word bigint_add3_nc(word z[], const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:250
word bigint_sub3(word z[], const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:342
const word * data() const
Definition: bigint.h:620
#define BOTAN_DEBUG_ASSERT(expr)
Definition: assert.h:123
void set_words(const word w[], size_t len)
Definition: bigint.h:518
Mask< T > conditional_copy_mem(T cnd, T *to, const T *from0, const T *from1, size_t elems)
Definition: ct_utils.h:363
#define BOTAN_ARG_CHECK(expr, msg)
Definition: assert.h:37
void grow_to(size_t n) const
Definition: bigint.h:636

◆ mod_mul()

BigInt & Botan::BigInt::mod_mul ( uint8_t  y,
const BigInt mod,
secure_vector< word > &  ws 
)

Set *this to (*this * y) % mod This function assumes *this is >= 0 && < mod y should be small, less than 16

Parameters
ythe small integer to multiply by
modthe positive modulus
wsa temp workspace

Definition at line 120 of file big_ops2.cpp.

References BOTAN_ARG_CHECK, BOTAN_DEBUG_ASSERT, is_negative(), and reduce_below().

Referenced by Botan::Montgomery_Int::mul_by_2(), Botan::Montgomery_Int::mul_by_3(), Botan::Montgomery_Int::mul_by_4(), Botan::Montgomery_Int::mul_by_8(), and Botan::PointGFp::mult2().

121  {
122  BOTAN_ARG_CHECK(this->is_negative() == false, "*this must be positive");
123  BOTAN_ARG_CHECK(y < 16, "y too large");
124 
125  BOTAN_DEBUG_ASSERT(*this < mod);
126 
127  *this *= static_cast<word>(y);
128  this->reduce_below(mod, ws);
129  return (*this);
130  }
bool is_negative() const
Definition: bigint.h:527
#define BOTAN_DEBUG_ASSERT(expr)
Definition: assert.h:123
#define BOTAN_ARG_CHECK(expr, msg)
Definition: assert.h:37
size_t reduce_below(const BigInt &mod, secure_vector< word > &ws)
Definition: bigint.cpp:336

◆ mod_sub()

BigInt & Botan::BigInt::mod_sub ( const BigInt y,
const BigInt mod,
secure_vector< word > &  ws 
)

Set *this to (*this - y) % mod This function assumes *this is >= 0 && < mod

Parameters
ythe BigInt to subtract - assumed y >= 0 and y < mod
modthe positive modulus
wsa temp workspace

Definition at line 93 of file big_ops2.cpp.

References Botan::bigint_mod_sub(), BOTAN_DEBUG_ASSERT, data(), grow_to(), is_negative(), mutable_data(), and sig_words().

Referenced by Botan::PointGFp::add(), Botan::PointGFp::add_affine(), Botan::PointGFp::mult2(), Botan::Montgomery_Int::operator-(), and Botan::Montgomery_Int::sub().

94  {
95  if(this->is_negative() || s.is_negative() || mod.is_negative())
96  throw Invalid_Argument("BigInt::mod_sub expects all arguments are positive");
97 
98  // We are assuming in this function that *this and s are no more than mod_sw words long
99  BOTAN_DEBUG_ASSERT(*this < mod);
100  BOTAN_DEBUG_ASSERT(s < mod);
101 
102  const size_t mod_sw = mod.sig_words();
103 
104  this->grow_to(mod_sw);
105  s.grow_to(mod_sw);
106 
107  if(ws.size() < mod_sw)
108  ws.resize(mod_sw);
109 
110  if(mod_sw == 4)
111  bigint_mod_sub_n<4>(mutable_data(), s.data(), mod.data(), ws.data());
112  else if(mod_sw == 6)
113  bigint_mod_sub_n<6>(mutable_data(), s.data(), mod.data(), ws.data());
114  else
115  bigint_mod_sub(mutable_data(), s.data(), mod.data(), mod_sw, ws.data());
116 
117  return (*this);
118  }
bool is_negative() const
Definition: bigint.h:527
word * mutable_data()
Definition: bigint.h:614
#define BOTAN_DEBUG_ASSERT(expr)
Definition: assert.h:123
void grow_to(size_t n) const
Definition: bigint.h:636
void bigint_mod_sub(word t[], const word s[], const word mod[], size_t mod_sw, word ws[])
Definition: mp_core.h:687

◆ mul()

BigInt & Botan::BigInt::mul ( const BigInt y,
secure_vector< word > &  ws 
)

Multiply this with y

Parameters
ythe BigInt to multiply with this
wsa temp workspace

Definition at line 159 of file big_ops2.cpp.

References Botan::bigint_linmul2(), Botan::bigint_linmul3(), Botan::bigint_mul(), Botan::carry(), clear(), data(), grow_to(), mutable_data(), Negative, Positive, set_sign(), set_word_at(), sig_words(), sign(), size(), swap_reg(), and word_at().

Referenced by operator*=(), and Botan::Modular_Reducer::reduce().

160  {
161  const size_t x_sw = sig_words();
162  const size_t y_sw = y.sig_words();
163  set_sign((sign() == y.sign()) ? Positive : Negative);
164 
165  if(x_sw == 0 || y_sw == 0)
166  {
167  clear();
169  }
170  else if(x_sw == 1 && y_sw)
171  {
172  grow_to(y_sw + 1);
173  bigint_linmul3(mutable_data(), y.data(), y_sw, word_at(0));
174  }
175  else if(y_sw == 1 && x_sw)
176  {
177  word carry = bigint_linmul2(mutable_data(), x_sw, y.word_at(0));
178  set_word_at(x_sw, carry);
179  }
180  else
181  {
182  const size_t new_size = x_sw + y_sw + 1;
183  ws.resize(new_size);
184  secure_vector<word> z_reg(new_size);
185 
186  bigint_mul(z_reg.data(), z_reg.size(),
187  data(), size(), x_sw,
188  y.data(), y.size(), y_sw,
189  ws.data(), ws.size());
190 
191  this->swap_reg(z_reg);
192  }
193 
194  return (*this);
195  }
void carry(int64_t &h0, int64_t &h1)
word BOTAN_WARN_UNUSED_RESULT bigint_linmul2(word x[], size_t x_size, word y)
Definition: mp_core.h:489
Sign sign() const
Definition: bigint.h:539
word * mutable_data()
Definition: bigint.h:614
void swap_reg(secure_vector< word > &reg)
Definition: bigint.h:167
word word_at(size_t n) const
Definition: bigint.h:508
const word * data() const
Definition: bigint.h:620
void bigint_linmul3(word z[], const word x[], size_t x_size, word y)
Definition: mp_core.h:504
size_t size() const
Definition: bigint.h:580
size_t sig_words() const
Definition: bigint.h:586
void bigint_mul(word z[], size_t z_size, const word x[], size_t x_size, size_t x_sw, const word y[], size_t y_size, size_t y_sw, word workspace[], size_t ws_size)
Definition: mp_karat.cpp:298
void clear()
Definition: bigint.h:366
void grow_to(size_t n) const
Definition: bigint.h:636
void set_word_at(size_t i, word w)
Definition: bigint.h:513
void set_sign(Sign sign)
Definition: bigint.h:563

◆ mutable_data()

word* Botan::BigInt::mutable_data ( )
inline

◆ operator!()

bool Botan::BigInt::operator! ( ) const
inline

! operator

Returns
true iff this is zero, otherwise false

Definition at line 281 of file bigint.h.

281 { return (!is_nonzero()); }
bool is_nonzero() const
Definition: bigint.h:415

◆ operator%=() [1/2]

BigInt & Botan::BigInt::operator%= ( const BigInt y)

Modulo operator

Parameters
ythe modulus to reduce this by

Definition at line 243 of file big_ops2.cpp.

244  {
245  return (*this = (*this) % mod);
246  }

◆ operator%=() [2/2]

word Botan::BigInt::operator%= ( word  y)

Modulo operator

Parameters
ythe modulus (word) to reduce this by

Definition at line 251 of file big_ops2.cpp.

References Botan::bigint_modop(), Botan::is_power_of_2(), Negative, Positive, set_sign(), sig_words(), sign(), and word_at().

252  {
253  if(mod == 0)
254  throw BigInt::DivideByZero();
255 
256  word remainder = 0;
257 
258  if(is_power_of_2(mod))
259  {
260  remainder = (word_at(0) & (mod - 1));
261  }
262  else
263  {
264  const size_t sw = sig_words();
265  for(size_t i = sw; i > 0; --i)
266  remainder = bigint_modop(remainder, word_at(i-1), mod);
267  }
268 
269  if(remainder && sign() == BigInt::Negative)
270  remainder = mod - remainder;
271 
272  m_data.set_to_zero();
273  m_data.set_word_at(0, remainder);
275  return remainder;
276  }
Sign sign() const
Definition: bigint.h:539
word word_at(size_t n) const
Definition: bigint.h:508
constexpr bool is_power_of_2(T arg)
Definition: bit_ops.h:43
size_t sig_words() const
Definition: bigint.h:586
void set_sign(Sign sign)
Definition: bigint.h:563
word bigint_modop(word n1, word n0, word d)
Definition: mp_core.h:755

◆ operator*=() [1/2]

BigInt & Botan::BigInt::operator*= ( const BigInt y)

*= operator

Parameters
ythe BigInt to multiply with this

Definition at line 153 of file big_ops2.cpp.

References mul().

154  {
155  secure_vector<word> ws;
156  return this->mul(y, ws);
157  }
BigInt & mul(const BigInt &y, secure_vector< word > &ws)
Definition: big_ops2.cpp:159

◆ operator*=() [2/2]

BigInt & Botan::BigInt::operator*= ( word  y)

*= operator

Parameters
ythe word to multiply with this

Definition at line 214 of file big_ops2.cpp.

References Botan::bigint_linmul2(), Botan::carry(), clear(), mutable_data(), Positive, set_sign(), set_word_at(), and size().

215  {
216  if(y == 0)
217  {
218  clear();
220  }
221 
222  const word carry = bigint_linmul2(mutable_data(), size(), y);
223  set_word_at(size(), carry);
224 
225  return (*this);
226  }
void carry(int64_t &h0, int64_t &h1)
word BOTAN_WARN_UNUSED_RESULT bigint_linmul2(word x[], size_t x_size, word y)
Definition: mp_core.h:489
word * mutable_data()
Definition: bigint.h:614
size_t size() const
Definition: bigint.h:580
void clear()
Definition: bigint.h:366
void set_word_at(size_t i, word w)
Definition: bigint.h:513
void set_sign(Sign sign)
Definition: bigint.h:563

◆ operator++() [1/2]

BigInt& Botan::BigInt::operator++ ( )
inline

Increment operator

Definition at line 254 of file bigint.h.

254 { return (*this += 1); }

◆ operator++() [2/2]

BigInt Botan::BigInt::operator++ ( int  )
inline

Postfix increment operator

Definition at line 264 of file bigint.h.

264 { BigInt x = (*this); ++(*this); return x; }
BigInt()=default

◆ operator+=() [1/2]

BigInt& Botan::BigInt::operator+= ( const BigInt y)
inline

+= operator

Parameters
ythe BigInt to add to this

Definition at line 177 of file bigint.h.

References data(), sig_words(), and sign().

178  {
179  return add(y.data(), y.sig_words(), y.sign());
180  }
BigInt & add(const word y[], size_t y_words, Sign sign)
Definition: big_ops2.cpp:15

◆ operator+=() [2/2]

BigInt& Botan::BigInt::operator+= ( word  y)
inline

+= operator

Parameters
ythe word to add to this

Definition at line 186 of file bigint.h.

187  {
188  return add(&y, 1, Positive);
189  }
BigInt & add(const word y[], size_t y_words, Sign sign)
Definition: big_ops2.cpp:15

◆ operator-()

BigInt Botan::BigInt::operator- ( ) const

Unary negation operator

Returns
negative this

Definition at line 329 of file bigint.cpp.

References flip_sign().

330  {
331  BigInt x = (*this);
332  x.flip_sign();
333  return x;
334  }
BigInt()=default

◆ operator--() [1/2]

BigInt& Botan::BigInt::operator-- ( )
inline

Decrement operator

Definition at line 259 of file bigint.h.

259 { return (*this -= 1); }

◆ operator--() [2/2]

BigInt Botan::BigInt::operator-- ( int  )
inline

Postfix decrement operator

Definition at line 269 of file bigint.h.

269 { BigInt x = (*this); --(*this); return x; }
BigInt()=default

◆ operator-=() [1/2]

BigInt& Botan::BigInt::operator-= ( const BigInt y)
inline

-= operator

Parameters
ythe BigInt to subtract from this

Definition at line 195 of file bigint.h.

References data(), sig_words(), and sign().

196  {
197  return sub(y.data(), y.sig_words(), y.sign());
198  }
BigInt & sub(const word y[], size_t y_words, Sign sign)
Definition: bigint.h:287

◆ operator-=() [2/2]

BigInt& Botan::BigInt::operator-= ( word  y)
inline

-= operator

Parameters
ythe word to subtract from this

Definition at line 204 of file bigint.h.

205  {
206  return sub(&y, 1, Positive);
207  }
BigInt & sub(const word y[], size_t y_words, Sign sign)
Definition: bigint.h:287

◆ operator/=()

BigInt & Botan::BigInt::operator/= ( const BigInt y)

/= operator

Parameters
ythe BigInt to divide this by

Definition at line 231 of file big_ops2.cpp.

References bits(), Botan::is_power_of_2(), sig_words(), and word_at().

232  {
233  if(y.sig_words() == 1 && is_power_of_2(y.word_at(0)))
234  (*this) >>= (y.bits() - 1);
235  else
236  (*this) = (*this) / y;
237  return (*this);
238  }
constexpr bool is_power_of_2(T arg)
Definition: bit_ops.h:43

◆ operator<<=()

BigInt & Botan::BigInt::operator<<= ( size_t  shift)

Left shift operator

Parameters
shiftthe number of bits to shift this left by

Definition at line 281 of file big_ops2.cpp.

References Botan::bigint_shl1(), sig_words(), size(), and top_bits_free().

282  {
283  const size_t shift_words = shift / BOTAN_MP_WORD_BITS;
284  const size_t shift_bits = shift % BOTAN_MP_WORD_BITS;
285  const size_t size = sig_words();
286 
287  const size_t bits_free = top_bits_free();
288 
289  const size_t new_size = size + shift_words + (bits_free < shift_bits);
290 
291  m_data.grow_to(new_size);
292 
293  bigint_shl1(m_data.mutable_data(), new_size, size, shift_words, shift_bits);
294 
295  return (*this);
296  }
void bigint_shl1(word x[], size_t x_size, size_t x_words, size_t word_shift, size_t bit_shift)
Definition: mp_core.h:409
size_t size() const
Definition: bigint.h:580
size_t sig_words() const
Definition: bigint.h:586
size_t top_bits_free() const
Definition: bigint.cpp:286

◆ operator=() [1/2]

BigInt& Botan::BigInt::operator= ( BigInt &&  other)
inline

Move assignment

Definition at line 144 of file bigint.h.

145  {
146  if(this != &other)
147  this->swap(other);
148 
149  return (*this);
150  }
void swap(BigInt &other)
Definition: bigint.h:161

◆ operator=() [2/2]

BigInt& Botan::BigInt::operator= ( const BigInt )
default

Copy assignment

◆ operator>>=()

BigInt & Botan::BigInt::operator>>= ( size_t  shift)

Right shift operator

Parameters
shiftthe number of bits to shift this right by

Definition at line 301 of file big_ops2.cpp.

References Botan::bigint_shr1(), is_negative(), is_zero(), Positive, and set_sign().

302  {
303  const size_t shift_words = shift / BOTAN_MP_WORD_BITS;
304  const size_t shift_bits = shift % BOTAN_MP_WORD_BITS;
305 
306  bigint_shr1(m_data.mutable_data(), m_data.size(), shift_words, shift_bits);
307 
308  if(is_negative() && is_zero())
310 
311  return (*this);
312  }
void bigint_shr1(word x[], size_t x_size, size_t word_shift, size_t bit_shift)
Definition: mp_core.h:427
bool is_negative() const
Definition: bigint.h:527
bool is_zero() const
Definition: bigint.h:421
void set_sign(Sign sign)
Definition: bigint.h:563

◆ power_of_2()

static BigInt Botan::BigInt::power_of_2 ( size_t  n)
inlinestatic

Create a power of two

Parameters
nthe power of two to create
Returns
bigint representing 2^n

Definition at line 758 of file bigint.h.

References set_bit().

Referenced by Botan::inverse_mod(), Botan::is_perfect_square(), Botan::Montgomery_Params::Montgomery_Params(), and Botan::ressol().

759  {
760  BigInt b;
761  b.set_bit(n);
762  return b;
763  }
BigInt()=default

◆ random_integer()

BigInt Botan::BigInt::random_integer ( RandomNumberGenerator rng,
const BigInt min,
const BigInt max 
)
static
Parameters
rnga random number generator
minthe minimum value (must be non-negative)
maxthe maximum value (must be non-negative and > min)
Returns
random integer in [min,max)

Definition at line 45 of file big_rand.cpp.

References bits(), is_negative(), and randomize().

Referenced by botan_mp_rand_range(), Botan::DSA_PrivateKey::DSA_PrivateKey(), Botan::is_miller_rabin_probable_prime(), Botan::EC_Group::random_scalar(), and Botan::PointGFp::randomize_repr().

47  {
48  if(min.is_negative() || max.is_negative() || max <= min)
49  throw Invalid_Argument("BigInt::random_integer invalid range");
50 
51  BigInt r;
52 
53  const size_t bits = max.bits();
54 
55  do
56  {
57  r.randomize(rng, bits, false);
58  }
59  while(r < min || r >= max);
60 
61  return r;
62  }
size_t bits() const
Definition: bigint.cpp:296
BigInt()=default

◆ randomize()

void Botan::BigInt::randomize ( RandomNumberGenerator rng,
size_t  bitsize,
bool  set_high_bit = true 
)

Fill BigInt with a random number with size of bitsize

If set_high_bit is true, the highest bit will be set, which causes the entropy to be bits-1. Otherwise the highest bit is randomly chosen by the rng, causing the entropy to be bits.

Parameters
rngthe random number generator to use
bitsizenumber of bits the created random value should have
set_high_bitif true, the highest bit is always set

Definition at line 17 of file big_rand.cpp.

References binary_decode(), clear(), Positive, Botan::RandomNumberGenerator::random_vec(), Botan::round_up(), and set_sign().

Referenced by BigInt(), Botan::DH_PrivateKey::DH_PrivateKey(), Botan::ElGamal_PrivateKey::ElGamal_PrivateKey(), and random_integer().

19  {
21 
22  if(bitsize == 0)
23  {
24  clear();
25  }
26  else
27  {
28  secure_vector<uint8_t> array = rng.random_vec(round_up(bitsize, 8) / 8);
29 
30  // Always cut unwanted bits
31  if(bitsize % 8)
32  array[0] &= 0xFF >> (8 - (bitsize % 8));
33 
34  // Set the highest bit if wanted
35  if (set_high_bit)
36  array[0] |= 0x80 >> ((bitsize % 8) ? (8 - bitsize % 8) : 0);
37 
38  binary_decode(array);
39  }
40  }
void clear()
Definition: bigint.h:366
void binary_decode(const uint8_t buf[], size_t length)
Definition: bigint.cpp:432
size_t round_up(size_t n, size_t align_to)
Definition: rounding.h:21
void set_sign(Sign sign)
Definition: bigint.h:563

◆ reduce_below()

size_t Botan::BigInt::reduce_below ( const BigInt mod,
secure_vector< word > &  ws 
)

Return *this % mod

Assumes that *this is (if anything) only slightly larger than mod and performs repeated subtractions. It should not be used if *this is much larger than mod, instead use modulo operator.

Definition at line 336 of file bigint.cpp.

References Botan::bigint_sub3(), Botan::clear_mem(), data(), grow_to(), is_negative(), sig_words(), size(), and swap_reg().

Referenced by mod_mul(), and Botan::vartime_divide().

337  {
338  if(p.is_negative() || this->is_negative())
339  throw Invalid_Argument("BigInt::reduce_below both values must be positive");
340 
341  const size_t p_words = p.sig_words();
342 
343  if(size() < p_words + 1)
344  grow_to(p_words + 1);
345 
346  if(ws.size() < p_words + 1)
347  ws.resize(p_words + 1);
348 
349  clear_mem(ws.data(), ws.size());
350 
351  size_t reductions = 0;
352 
353  for(;;)
354  {
355  word borrow = bigint_sub3(ws.data(), data(), p_words + 1, p.data(), p_words);
356  if(borrow)
357  break;
358 
359  ++reductions;
360  swap_reg(ws);
361  }
362 
363  return reductions;
364  }
bool is_negative() const
Definition: bigint.h:527
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:115
void swap_reg(secure_vector< word > &reg)
Definition: bigint.h:167
word bigint_sub3(word z[], const word x[], size_t x_size, const word y[], size_t y_size)
Definition: mp_core.h:342
const word * data() const
Definition: bigint.h:620
size_t size() const
Definition: bigint.h:580
void grow_to(size_t n) const
Definition: bigint.h:636

◆ resize()

void Botan::BigInt::resize ( size_t  s)
inline

Definition at line 647 of file bigint.h.

Referenced by Botan::PointGFp::force_all_affine().

647 { m_data.resize(s); }

◆ rev_sub()

BigInt & Botan::BigInt::rev_sub ( const word  y[],
size_t  y_words,
secure_vector< word > &  ws 
)

Set *this to y - *this

Parameters
ythe BigInt to subtract from as a sequence of words
y_wordslength of y in words
wsa temp workspace

Definition at line 132 of file big_ops2.cpp.

References Botan::bigint_sub_abs(), Botan::clear_mem(), cond_flip_sign(), data(), Positive, sig_words(), sign(), and swap_reg().

Referenced by Botan::Modular_Reducer::reduce().

133  {
134  if(this->sign() != BigInt::Positive)
135  throw Invalid_State("BigInt::sub_rev requires this is positive");
136 
137  const size_t x_sw = this->sig_words();
138 
139  ws.resize(std::max(x_sw, y_sw));
140  clear_mem(ws.data(), ws.size());
141 
142  const int32_t relative_size = bigint_sub_abs(ws.data(), data(), x_sw, y, y_sw);
143 
144  this->cond_flip_sign(relative_size > 0);
145  this->swap_reg(ws);
146 
147  return (*this);
148  }
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:115
Sign sign() const
Definition: bigint.h:539
void swap_reg(secure_vector< word > &reg)
Definition: bigint.h:167
const word * data() const
Definition: bigint.h:620
CT::Mask< word > bigint_sub_abs(word z[], const word x[], const word y[], size_t N, word ws[])
Definition: mp_core.h:377
size_t sig_words() const
Definition: bigint.h:586
void cond_flip_sign(bool predicate)
Definition: bigint.cpp:475

◆ reverse_sign()

Sign Botan::BigInt::reverse_sign ( ) const
inline
Returns
the opposite sign of the represented integer value

Definition at line 544 of file bigint.h.

Referenced by Botan::operator-().

545  {
546  if(sign() == Positive)
547  return Negative;
548  return Positive;
549  }
Sign sign() const
Definition: bigint.h:539

◆ set_bit()

void Botan::BigInt::set_bit ( size_t  n)
inline

Set bit at specified position

Parameters
nbit position to set

Definition at line 430 of file bigint.h.

Referenced by botan_mp_set_bit(), Botan::generate_dsa_primes(), Botan::generate_rsa_prime(), Botan::Modular_Reducer::Modular_Reducer(), power_of_2(), and Botan::random_prime().

431  {
432  conditionally_set_bit(n, true);
433  }
void conditionally_set_bit(size_t n, bool set_it)
Definition: bigint.cpp:260

◆ set_sign()

void Botan::BigInt::set_sign ( Sign  sign)
inline

Set sign of the integer

Parameters
signnew Sign to set

Definition at line 563 of file bigint.h.

Referenced by abs(), add(), BigInt(), cond_flip_sign(), Botan::gcd(), Botan::inverse_mod(), mul(), operator%=(), Botan::operator*(), operator*=(), operator>>=(), randomize(), Botan::Modular_Reducer::reduce(), square(), to_dec_string(), and Botan::vartime_divide().

564  {
565  if(sign == Negative && is_zero())
566  sign = Positive;
567 
568  m_signedness = sign;
569  }
Sign sign() const
Definition: bigint.h:539
bool is_zero() const
Definition: bigint.h:421

◆ set_word_at()

void Botan::BigInt::set_word_at ( size_t  i,
word  w 
)
inline

Definition at line 513 of file bigint.h.

Referenced by ct_cond_assign(), mul(), and operator*=().

514  {
515  m_data.set_word_at(i, w);
516  }

◆ set_words()

void Botan::BigInt::set_words ( const word  w[],
size_t  len 
)
inline

Definition at line 518 of file bigint.h.

Referenced by Botan::PointGFp::add(), Botan::PointGFp::add_affine(), and mod_add().

519  {
520  m_data.set_words(w, len);
521  }

◆ shrink_to_fit()

void Botan::BigInt::shrink_to_fit ( size_t  min_size = 0)
inline

Resize the vector to the minimum word size to hold the integer, or min_size words, whichever is larger

Definition at line 642 of file bigint.h.

643  {
644  m_data.shrink_to_fit(min_size);
645  }

◆ sig_words()

size_t Botan::BigInt::sig_words ( ) const
inline

◆ sign()

Sign Botan::BigInt::sign ( ) const
inline

Return the sign of the integer

Returns
the sign of the integer

Definition at line 539 of file bigint.h.

Referenced by add(), add2(), cond_flip_sign(), ct_cond_assign(), is_equal(), mul(), Botan::mul_add(), Botan::operator%(), operator%=(), Botan::operator*(), Botan::operator+(), operator+=(), operator-=(), Botan::operator<<(), Botan::operator>>(), and rev_sub().

539 { return (m_signedness); }

◆ size()

size_t Botan::BigInt::size ( ) const
inline

◆ square()

BigInt & Botan::BigInt::square ( secure_vector< word > &  ws)

Square value of *this

Parameters
wsa temp workspace

Definition at line 197 of file big_ops2.cpp.

References Botan::bigint_sqr(), data(), Positive, set_sign(), sig_words(), size(), and swap_reg().

Referenced by Botan::square().

198  {
199  const size_t sw = sig_words();
200 
201  secure_vector<word> z(2*sw);
202  ws.resize(z.size());
203 
204  bigint_sqr(z.data(), z.size(),
205  data(), size(), sw,
206  ws.data(), ws.size());
207 
208  swap_reg(z);
210 
211  return (*this);
212  }
void swap_reg(secure_vector< word > &reg)
Definition: bigint.h:167
void bigint_sqr(word z[], size_t z_size, const word x[], size_t x_size, size_t x_sw, word workspace[], size_t ws_size)
Definition: mp_karat.cpp:357
const word * data() const
Definition: bigint.h:620
size_t size() const
Definition: bigint.h:580
size_t sig_words() const
Definition: bigint.h:586
void set_sign(Sign sign)
Definition: bigint.h:563

◆ sub()

BigInt& Botan::BigInt::sub ( const word  y[],
size_t  y_words,
Sign  sign 
)
inline

Definition at line 287 of file bigint.h.

288  {
289  return add(y, y_words, sign == Positive ? Negative : Positive);
290  }
Sign sign() const
Definition: bigint.h:539
BigInt & add(const word y[], size_t y_words, Sign sign)
Definition: big_ops2.cpp:15

◆ swap()

void Botan::BigInt::swap ( BigInt other)
inline

Swap this value with another

Parameters
otherBigInt to swap values with

Definition at line 161 of file bigint.h.

Referenced by Botan::PointGFp::add_affine(), botan_mp_swap(), Botan::PointGFp::mult2(), and Botan::PointGFp::swap().

162  {
163  m_data.swap(other.m_data);
164  std::swap(m_signedness, other.m_signedness);
165  }

◆ swap_reg()

void Botan::BigInt::swap_reg ( secure_vector< word > &  reg)
inline

Definition at line 167 of file bigint.h.

Referenced by mul(), reduce_below(), rev_sub(), and square().

168  {
169  m_data.swap(reg);
170  // sign left unchanged
171  }

◆ to_dec_string()

std::string Botan::BigInt::to_dec_string ( ) const

Convert this value to a decimal string. Warning: decimal conversions are relatively slow

Definition at line 15 of file big_code.cpp.

References Botan::ct_divide_u8(), Botan::Charset::digit2char(), Positive, and set_sign().

Referenced by encode(), encode_locked(), and Botan::operator<<().

16  {
17  BigInt copy = *this;
18  copy.set_sign(Positive);
19 
20  uint8_t remainder;
21  std::vector<uint8_t> digits;
22 
23  while(copy > 0)
24  {
25  ct_divide_u8(copy, 10, copy, remainder);
26  digits.push_back(remainder);
27  }
28 
29  std::string s;
30 
31  for(auto i = digits.rbegin(); i != digits.rend(); ++i)
32  {
33  s.push_back(Charset::digit2char(*i));
34  }
35 
36  if(s.empty())
37  s += "0";
38 
39  return s;
40  }
void ct_divide_u8(const BigInt &x, uint8_t y, BigInt &q_out, uint8_t &r_out)
Definition: divide.cpp:82
char digit2char(uint8_t b)
Definition: charset.cpp:253
BigInt()=default

◆ to_hex_string()

std::string Botan::BigInt::to_hex_string ( ) const

Convert this value to a hexadecimal string.

Definition at line 42 of file big_code.cpp.

References bits(), encode(), and Botan::hex_encode().

Referenced by botan_mp_to_hex(), encode(), encode_locked(), and Botan::operator<<().

43  {
44  const std::vector<uint8_t> bits = BigInt::encode(*this);
45  if(bits.empty())
46  return "00";
47  else
48  return hex_encode(bits);
49  }
void hex_encode(char output[], const uint8_t input[], size_t input_length, bool uppercase)
Definition: hex.cpp:31
size_t bits() const
Definition: bigint.cpp:296
static std::vector< uint8_t > encode(const BigInt &n)
Definition: bigint.h:770

◆ to_u32bit()

uint32_t Botan::BigInt::to_u32bit ( ) const

Convert this value into a uint32_t, if it is in the range [0 ... 2**32-1], or otherwise throw an exception.

Returns
the value as a uint32_t if conversion is possible

Definition at line 244 of file bigint.cpp.

References bits(), byte_at(), and is_negative().

Referenced by botan_mp_to_uint32().

245  {
246  if(is_negative())
247  throw Encoding_Error("BigInt::to_u32bit: Number is negative");
248  if(bits() > 32)
249  throw Encoding_Error("BigInt::to_u32bit: Number is too big to convert");
250 
251  uint32_t out = 0;
252  for(size_t i = 0; i != 4; ++i)
253  out = (out << 8) | byte_at(3-i);
254  return out;
255  }
bool is_negative() const
Definition: bigint.h:527
size_t bits() const
Definition: bigint.cpp:296
uint8_t byte_at(size_t n) const
Definition: bigint.cpp:109

◆ top_bits_free()

size_t Botan::BigInt::top_bits_free ( ) const

Get the number of high bits unset in the top (allocated) word of this integer. Returns BOTAN_MP_WORD_BITS only iff *this is zero. Ignores sign.

Definition at line 286 of file bigint.cpp.

References Botan::high_bit(), sig_words(), Botan::CT::unpoison(), and word_at().

Referenced by bits(), operator<<=(), and Botan::vartime_divide().

287  {
288  const size_t words = sig_words();
289 
290  const word top_word = word_at(words - 1);
291  const size_t bits_used = high_bit(top_word);
292  CT::unpoison(bits_used);
293  return BOTAN_MP_WORD_BITS - bits_used;
294  }
word word_at(size_t n) const
Definition: bigint.h:508
size_t high_bit(T n)
Definition: bit_ops.h:55
size_t sig_words() const
Definition: bigint.h:586
void unpoison(const T *p, size_t n)
Definition: ct_utils.h:59

◆ word_at()

word Botan::BigInt::word_at ( size_t  n) const
inline

Return the word at a specified position of the internal register

Parameters
nposition in the register
Returns
value at position n

Definition at line 508 of file bigint.h.

Referenced by binary_encode(), byte_at(), clear_bit(), conditionally_set_bit(), ct_cond_assign(), get_substring(), Botan::is_prime(), Botan::low_zero_bits(), Botan::Montgomery_Params::Montgomery_Params(), mul(), Botan::operator%(), operator%=(), Botan::operator*(), Botan::operator/(), operator/=(), Botan::redc_p521(), top_bits_free(), and Botan::vartime_divide().

509  {
510  return m_data.get_word_at(n);
511  }

The documentation for this class was generated from the following files: