ext-cryptopp/integer.h
Jeffrey Walton 2c9a3039e8
Update documentation
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// integer.h - originally written and placed in the public domain by Wei Dai
//! \file integer.h
//! \brief Multiple precision integer with arithmetic operations
//! \details The Integer class can represent positive and negative integers
//! with absolute value less than (256**sizeof(word))<sup>(256**sizeof(int))</sup>.
//! \details Internally, the library uses a sign magnitude representation, and the class
//! has two data members. The first is a IntegerSecBlock (a SecBlock<word>) and it is
//! used to hold the representation. The second is a Sign (an enumeration), and it is
//! used to track the sign of the Integer.
//! \details For details on how the Integer class initializes its function pointers using
//! InitializeInteger and how it creates Integer::Zero(), Integer::One(), and
//! Integer::Two(), then see the comments at the top of <tt>integer.cpp</tt>.
//! \since Crypto++ 1.0
#ifndef CRYPTOPP_INTEGER_H
#define CRYPTOPP_INTEGER_H
#include "cryptlib.h"
#include "secblock.h"
#include "stdcpp.h"
#include <iosfwd>
NAMESPACE_BEGIN(CryptoPP)
//! \struct InitializeInteger
//! \brief Performs static initialization of the Integer class
struct InitializeInteger
{
InitializeInteger();
};
// Always align, http://github.com/weidai11/cryptopp/issues/256
typedef SecBlock<word, AllocatorWithCleanup<word, true> > IntegerSecBlock;
//! \brief Multiple precision integer with arithmetic operations
//! \details The Integer class can represent positive and negative integers
//! with absolute value less than (256**sizeof(word))<sup>(256**sizeof(int))</sup>.
//! \details Internally, the library uses a sign magnitude representation, and the class
//! has two data members. The first is a IntegerSecBlock (a SecBlock<word>) and it is
//! used to hold the representation. The second is a Sign (an enumeration), and it is
//! used to track the sign of the Integer.
//! \details For details on how the Integer class initializes its function pointers using
//! InitializeInteger and how it creates Integer::Zero(), Integer::One(), and
//! Integer::Two(), then see the comments at the top of <tt>integer.cpp</tt>.
//! \since Crypto++ 1.0
//! \nosubgrouping
class CRYPTOPP_DLL Integer : private InitializeInteger, public ASN1Object
{
public:
//! \name ENUMS, EXCEPTIONS, and TYPEDEFS
//@{
//! \brief Exception thrown when division by 0 is encountered
class DivideByZero : public Exception
{
public:
DivideByZero() : Exception(OTHER_ERROR, "Integer: division by zero") {}
};
//! \brief Exception thrown when a random number cannot be found that
//! satisfies the condition
class RandomNumberNotFound : public Exception
{
public:
RandomNumberNotFound() : Exception(OTHER_ERROR, "Integer: no integer satisfies the given parameters") {}
};
//! \enum Sign
//! \brief Used internally to represent the integer
//! \details Sign is used internally to represent the integer. It is also used in a few API functions.
//! \sa SetPositive(), SetNegative(), Signedness
enum Sign {
//! \brief the value is positive or 0
POSITIVE=0,
//! \brief the value is negative
NEGATIVE=1};
//! \enum Signedness
//! \brief Used when importing and exporting integers
//! \details Signedness is usually used in API functions.
//! \sa Sign
enum Signedness {
//! \brief an unsigned value
UNSIGNED,
//! \brief a signed value
SIGNED};
//! \enum RandomNumberType
//! \brief Properties of a random integer
enum RandomNumberType {
//! \brief a number with no special properties
ANY,
//! \brief a number which is probabilistically prime
PRIME};
//@}
//! \name CREATORS
//@{
//! \brief Creates the zero integer
Integer();
//! copy constructor
Integer(const Integer& t);
//! \brief Convert from signed long
Integer(signed long value);
//! \brief Convert from lword
//! \param sign enumeration indicating Sign
//! \param value the long word
Integer(Sign sign, lword value);
//! \brief Convert from two words
//! \param sign enumeration indicating Sign
//! \param highWord the high word
//! \param lowWord the low word
Integer(Sign sign, word highWord, word lowWord);
//! \brief Convert from a C-string
//! \param str C-string value
//! \param order the ByteOrder of the string to be processed
//! \details \p str can be in base 2, 8, 10, or 16. Base is determined by a case
//! insensitive suffix of 'h', 'o', or 'b'. No suffix means base 10.
//! \details Byte order was added at Crypto++ 5.7 to allow use of little-endian
//! integers with curve25519, Poly1305 and Microsoft CAPI.
explicit Integer(const char *str, ByteOrder order = BIG_ENDIAN_ORDER);
//! \brief Convert from a wide C-string
//! \param str wide C-string value
//! \param order the ByteOrder of the string to be processed
//! \details \p str can be in base 2, 8, 10, or 16. Base is determined by a case
//! insensitive suffix of 'h', 'o', or 'b'. No suffix means base 10.
//! \details Byte order was added at Crypto++ 5.7 to allow use of little-endian
//! integers with curve25519, Poly1305 and Microsoft CAPI.
explicit Integer(const wchar_t *str, ByteOrder order = BIG_ENDIAN_ORDER);
//! \brief Convert from a big-endian byte array
//! \param encodedInteger big-endian byte array
//! \param byteCount length of the byte array
//! \param sign enumeration indicating Signedness
//! \param order the ByteOrder of the array to be processed
//! \details Byte order was added at Crypto++ 5.7 to allow use of little-endian
//! integers with curve25519, Poly1305 and Microsoft CAPI.
Integer(const byte *encodedInteger, size_t byteCount, Signedness sign=UNSIGNED, ByteOrder order = BIG_ENDIAN_ORDER);
//! \brief Convert from a big-endian array
//! \param bt BufferedTransformation object with big-endian byte array
//! \param byteCount length of the byte array
//! \param sign enumeration indicating Signedness
//! \param order the ByteOrder of the data to be processed
//! \details Byte order was added at Crypto++ 5.7 to allow use of little-endian
//! integers with curve25519, Poly1305 and Microsoft CAPI.
Integer(BufferedTransformation &bt, size_t byteCount, Signedness sign=UNSIGNED, ByteOrder order = BIG_ENDIAN_ORDER);
//! \brief Convert from a BER encoded byte array
//! \param bt BufferedTransformation object with BER encoded byte array
explicit Integer(BufferedTransformation &bt);
//! \brief Create a random integer
//! \param rng RandomNumberGenerator used to generate material
//! \param bitCount the number of bits in the resulting integer
//! \details The random integer created is uniformly distributed over <tt>[0, 2<sup>bitCount</sup>]</tt>.
Integer(RandomNumberGenerator &rng, size_t bitCount);
//! \brief Integer representing 0
//! \returns an Integer representing 0
//! \details Zero() avoids calling constructors for frequently used integers
static const Integer & CRYPTOPP_API Zero();
//! \brief Integer representing 1
//! \returns an Integer representing 1
//! \details One() avoids calling constructors for frequently used integers
static const Integer & CRYPTOPP_API One();
//! \brief Integer representing 2
//! \returns an Integer representing 2
//! \details Two() avoids calling constructors for frequently used integers
static const Integer & CRYPTOPP_API Two();
//! \brief Create a random integer of special form
//! \param rng RandomNumberGenerator used to generate material
//! \param min the minimum value
//! \param max the maximum value
//! \param rnType RandomNumberType to specify the type
//! \param equiv the equivalence class based on the parameter \p mod
//! \param mod the modulus used to reduce the equivalence class
//! \throw RandomNumberNotFound if the set is empty.
//! \details Ideally, the random integer created should be uniformly distributed
//! over <tt>{x | min \<= x \<= max</tt> and \p x is of rnType and <tt>x \% mod == equiv}</tt>.
//! However the actual distribution may not be uniform because sequential
//! search is used to find an appropriate number from a random starting
//! point.
//! \details May return (with very small probability) a pseudoprime when a prime
//! is requested and <tt>max \> lastSmallPrime*lastSmallPrime</tt>. \p lastSmallPrime
//! is declared in nbtheory.h.
Integer(RandomNumberGenerator &rng, const Integer &min, const Integer &max, RandomNumberType rnType=ANY, const Integer &equiv=Zero(), const Integer &mod=One());
//! \brief Exponentiates to a power of 2
//! \returns the Integer 2<sup>e</sup>
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
static Integer CRYPTOPP_API Power2(size_t e);
//@}
//! \name ENCODE/DECODE
//@{
//! \brief Minimum number of bytes to encode this integer
//! \param sign enumeration indicating Signedness
//! \note The MinEncodedSize() of 0 is 1.
size_t MinEncodedSize(Signedness sign=UNSIGNED) const;
//! \brief Encode in big-endian format
//! \param output big-endian byte array
//! \param outputLen length of the byte array
//! \param sign enumeration indicating Signedness
//! \details Unsigned means encode absolute value, signed means encode two's complement if negative.
//! \details outputLen can be used to ensure an Integer is encoded to an exact size (rather than a
//! minimum size). An exact size is useful, for example, when encoding to a field element size.
void Encode(byte *output, size_t outputLen, Signedness sign=UNSIGNED) const;
//! \brief Encode in big-endian format
//! \param bt BufferedTransformation object
//! \param outputLen length of the encoding
//! \param sign enumeration indicating Signedness
//! \details Unsigned means encode absolute value, signed means encode two's complement if negative.
//! \details outputLen can be used to ensure an Integer is encoded to an exact size (rather than a
//! minimum size). An exact size is useful, for example, when encoding to a field element size.
void Encode(BufferedTransformation &bt, size_t outputLen, Signedness sign=UNSIGNED) const;
//! \brief Encode in DER format
//! \param bt BufferedTransformation object
//! \details Encodes the Integer using Distinguished Encoding Rules
//! The result is placed into a BufferedTransformation object
void DEREncode(BufferedTransformation &bt) const;
//! \brief Encode absolute value as big-endian octet string
//! \param bt BufferedTransformation object
//! \param length the number of mytes to decode
void DEREncodeAsOctetString(BufferedTransformation &bt, size_t length) const;
//! \brief Encode absolute value in OpenPGP format
//! \param output big-endian byte array
//! \param bufferSize length of the byte array
//! \returns length of the output
//! \details OpenPGPEncode places result into the buffer and returns the
//! number of bytes used for the encoding
size_t OpenPGPEncode(byte *output, size_t bufferSize) const;
//! \brief Encode absolute value in OpenPGP format
//! \param bt BufferedTransformation object
//! \returns length of the output
//! \details OpenPGPEncode places result into a BufferedTransformation object and returns the
//! number of bytes used for the encoding
size_t OpenPGPEncode(BufferedTransformation &bt) const;
//! \brief Decode from big-endian byte array
//! \param input big-endian byte array
//! \param inputLen length of the byte array
//! \param sign enumeration indicating Signedness
void Decode(const byte *input, size_t inputLen, Signedness sign=UNSIGNED);
//! \brief Decode nonnegative value from big-endian byte array
//! \param bt BufferedTransformation object
//! \param inputLen length of the byte array
//! \param sign enumeration indicating Signedness
//! \note <tt>bt.MaxRetrievable() \>= inputLen</tt>.
void Decode(BufferedTransformation &bt, size_t inputLen, Signedness sign=UNSIGNED);
//! \brief Decode from BER format
//! \param input big-endian byte array
//! \param inputLen length of the byte array
void BERDecode(const byte *input, size_t inputLen);
//! \brief Decode from BER format
//! \param bt BufferedTransformation object
void BERDecode(BufferedTransformation &bt);
//! \brief Decode nonnegative value from big-endian octet string
//! \param bt BufferedTransformation object
//! \param length length of the byte array
void BERDecodeAsOctetString(BufferedTransformation &bt, size_t length);
//! \brief Exception thrown when an error is encountered decoding an OpenPGP integer
class OpenPGPDecodeErr : public Exception
{
public:
OpenPGPDecodeErr() : Exception(INVALID_DATA_FORMAT, "OpenPGP decode error") {}
};
//! \brief Decode from OpenPGP format
//! \param input big-endian byte array
//! \param inputLen length of the byte array
void OpenPGPDecode(const byte *input, size_t inputLen);
//! \brief Decode from OpenPGP format
//! \param bt BufferedTransformation object
void OpenPGPDecode(BufferedTransformation &bt);
//@}
//! \name ACCESSORS
//@{
//! \brief Determines if the Integer is convertable to Long
//! \returns true if *this can be represented as a signed long
//! \sa ConvertToLong()
bool IsConvertableToLong() const;
//! \brief Convert the Integer to Long
//! \return equivalent signed long if possible, otherwise undefined
//! \sa IsConvertableToLong()
signed long ConvertToLong() const;
//! \brief Determines the number of bits required to represent the Integer
//! \returns number of significant bits = floor(log2(abs(*this))) + 1
unsigned int BitCount() const;
//! \brief Determines the number of bytes required to represent the Integer
//! \returns number of significant bytes = ceiling(BitCount()/8)
unsigned int ByteCount() const;
//! \brief Determines the number of words required to represent the Integer
//! \returns number of significant words = ceiling(ByteCount()/sizeof(word))
unsigned int WordCount() const;
//! \brief Provides the i-th bit of the Integer
//! \returns the i-th bit, i=0 being the least significant bit
bool GetBit(size_t i) const;
//! \brief Provides the i-th byte of the Integer
//! \returns the i-th byte
byte GetByte(size_t i) const;
//! \brief Provides the low order bits of the Integer
//! \returns n lowest bits of *this >> i
lword GetBits(size_t i, size_t n) const;
//! \brief Determines if the Integer is 0
//! \returns true if the Integer is 0, false otherwise
bool IsZero() const {return !*this;}
//! \brief Determines if the Integer is non-0
//! \returns true if the Integer is non-0, false otherwise
bool NotZero() const {return !IsZero();}
//! \brief Determines if the Integer is negative
//! \returns true if the Integer is negative, false otherwise
bool IsNegative() const {return sign == NEGATIVE;}
//! \brief Determines if the Integer is non-negative
//! \returns true if the Integer is non-negative, false otherwise
bool NotNegative() const {return !IsNegative();}
//! \brief Determines if the Integer is positive
//! \returns true if the Integer is positive, false otherwise
bool IsPositive() const {return NotNegative() && NotZero();}
//! \brief Determines if the Integer is non-positive
//! \returns true if the Integer is non-positive, false otherwise
bool NotPositive() const {return !IsPositive();}
//! \brief Determines if the Integer is even parity
//! \returns true if the Integer is even, false otherwise
bool IsEven() const {return GetBit(0) == 0;}
//! \brief Determines if the Integer is odd parity
//! \returns true if the Integer is odd, false otherwise
bool IsOdd() const {return GetBit(0) == 1;}
//@}
//! \name MANIPULATORS
//@{
//! \brief Assignment
Integer& operator=(const Integer& t);
//! \brief Addition Assignment
Integer& operator+=(const Integer& t);
//! \brief Subtraction Assignment
Integer& operator-=(const Integer& t);
//! \brief Multiplication Assignment
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
Integer& operator*=(const Integer& t) {return *this = Times(t);}
//! \brief Division Assignment
Integer& operator/=(const Integer& t) {return *this = DividedBy(t);}
//! \brief Remainder Assignment
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
Integer& operator%=(const Integer& t) {return *this = Modulo(t);}
//! \brief Division Assignment
Integer& operator/=(word t) {return *this = DividedBy(t);}
//! \brief Remainder Assignment
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
Integer& operator%=(word t) {return *this = Integer(POSITIVE, 0, Modulo(t));}
//! \brief Left-shift Assignment
Integer& operator<<=(size_t n);
//! \brief Right-shift Assignment
Integer& operator>>=(size_t n);
//! \brief Bitwise AND Assignment
//! \param t the other Integer
//! \returns the result of *this & t
//! \details operator&=() performs a bitwise AND on *this. Missing bits are truncated
//! at the most significant bit positions, so the result is as small as the
//! smaller of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
Integer& operator&=(const Integer& t);
//! \brief Bitwise OR Assignment
//! \param t the second Integer
//! \returns the result of *this | t
//! \details operator|=() performs a bitwise OR on *this. Missing bits are shifted in
//! at the most significant bit positions, so the result is as large as the
//! larger of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
Integer& operator|=(const Integer& t);
//! \brief Bitwise XOR Assignment
//! \param t the other Integer
//! \returns the result of *this ^ t
//! \details operator^=() performs a bitwise XOR on *this. Missing bits are shifted
//! in at the most significant bit positions, so the result is as large as the
//! larger of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
Integer& operator^=(const Integer& t);
//! \brief Set this Integer to random integer
//! \param rng RandomNumberGenerator used to generate material
//! \param bitCount the number of bits in the resulting integer
//! \details The random integer created is uniformly distributed over <tt>[0, 2<sup>bitCount</sup>]</tt>.
void Randomize(RandomNumberGenerator &rng, size_t bitCount);
//! \brief Set this Integer to random integer
//! \param rng RandomNumberGenerator used to generate material
//! \param min the minimum value
//! \param max the maximum value
//! \details The random integer created is uniformly distributed over <tt>[min, max]</tt>.
void Randomize(RandomNumberGenerator &rng, const Integer &min, const Integer &max);
//! \brief Set this Integer to random integer of special form
//! \param rng RandomNumberGenerator used to generate material
//! \param min the minimum value
//! \param max the maximum value
//! \param rnType RandomNumberType to specify the type
//! \param equiv the equivalence class based on the parameter \p mod
//! \param mod the modulus used to reduce the equivalence class
//! \throw RandomNumberNotFound if the set is empty.
//! \details Ideally, the random integer created should be uniformly distributed
//! over <tt>{x | min \<= x \<= max</tt> and \p x is of rnType and <tt>x \% mod == equiv}</tt>.
//! However the actual distribution may not be uniform because sequential
//! search is used to find an appropriate number from a random starting
//! point.
//! \details May return (with very small probability) a pseudoprime when a prime
//! is requested and <tt>max \> lastSmallPrime*lastSmallPrime</tt>. \p lastSmallPrime
//! is declared in nbtheory.h.
bool Randomize(RandomNumberGenerator &rng, const Integer &min, const Integer &max, RandomNumberType rnType, const Integer &equiv=Zero(), const Integer &mod=One());
bool GenerateRandomNoThrow(RandomNumberGenerator &rng, const NameValuePairs &params = g_nullNameValuePairs);
void GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &params = g_nullNameValuePairs)
{
if (!GenerateRandomNoThrow(rng, params))
throw RandomNumberNotFound();
}
//! \brief Set the n-th bit to value
//! \details 0-based numbering.
void SetBit(size_t n, bool value=1);
//! \brief Set the n-th byte to value
//! \details 0-based numbering.
void SetByte(size_t n, byte value);
//! \brief Reverse the Sign of the Integer
void Negate();
//! \brief Sets the Integer to positive
void SetPositive() {sign = POSITIVE;}
//! \brief Sets the Integer to negative
void SetNegative() {if (!!(*this)) sign = NEGATIVE;}
//! \brief Swaps this Integer with another Integer
void swap(Integer &a);
//@}
//! \name UNARY OPERATORS
//@{
//! \brief Negation
bool operator!() const;
//! \brief Addition
Integer operator+() const {return *this;}
//! \brief Subtraction
Integer operator-() const;
//! \brief Pre-increment
Integer& operator++();
//! \brief Pre-decrement
Integer& operator--();
//! \brief Post-increment
Integer operator++(int) {Integer temp = *this; ++*this; return temp;}
//! \brief Post-decrement
Integer operator--(int) {Integer temp = *this; --*this; return temp;}
//@}
//! \name BINARY OPERATORS
//@{
//! \brief Perform signed comparison
//! \param a the Integer to comapre
//! \retval -1 if <tt>*this < a</tt>
//! \retval 0 if <tt>*this = a</tt>
//! \retval 1 if <tt>*this > a</tt>
int Compare(const Integer& a) const;
//! \brief Addition
Integer Plus(const Integer &b) const;
//! \brief Subtraction
Integer Minus(const Integer &b) const;
//! \brief Multiplication
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
Integer Times(const Integer &b) const;
//! \brief Division
Integer DividedBy(const Integer &b) const;
//! \brief Remainder
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
Integer Modulo(const Integer &b) const;
//! \brief Division
Integer DividedBy(word b) const;
//! \brief Remainder
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
word Modulo(word b) const;
//! \brief Bitwise AND
//! \param t the other Integer
//! \returns the result of <tt>*this & t</tt>
//! \details And() performs a bitwise AND on the operands. Missing bits are truncated
//! at the most significant bit positions, so the result is as small as the
//! smaller of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
Integer And(const Integer& t) const;
//! \brief Bitwise OR
//! \param t the other Integer
//! \returns the result of <tt>*this | t</tt>
//! \details Or() performs a bitwise OR on the operands. Missing bits are shifted in
//! at the most significant bit positions, so the result is as large as the
//! larger of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
Integer Or(const Integer& t) const;
//! \brief Bitwise XOR
//! \param t the other Integer
//! \returns the result of <tt>*this ^ t</tt>
//! \details Xor() performs a bitwise XOR on the operands. Missing bits are shifted in
//! at the most significant bit positions, so the result is as large as the
//! larger of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
Integer Xor(const Integer& t) const;
//! \brief Right-shift
Integer operator>>(size_t n) const {return Integer(*this)>>=n;}
//! \brief Left-shift
Integer operator<<(size_t n) const {return Integer(*this)<<=n;}
//@}
//! \name OTHER ARITHMETIC FUNCTIONS
//@{
//! \brief Retrieve the absolute value of this integer
Integer AbsoluteValue() const;
//! \brief Add this integer to itself
Integer Doubled() const {return Plus(*this);}
//! \brief Multiply this integer by itself
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
Integer Squared() const {return Times(*this);}
//! \brief Extract square root
//! \details if negative return 0, else return floor of square root
Integer SquareRoot() const;
//! \brief Determine whether this integer is a perfect square
bool IsSquare() const;
//! is 1 or -1
bool IsUnit() const;
//! return inverse if 1 or -1, otherwise return 0
Integer MultiplicativeInverse() const;
//! \brief calculate r and q such that (a == d*q + r) && (0 <= r < abs(d))
static void CRYPTOPP_API Divide(Integer &r, Integer &q, const Integer &a, const Integer &d);
//! \brief use a faster division algorithm when divisor is short
static void CRYPTOPP_API Divide(word &r, Integer &q, const Integer &a, word d);
//! \brief returns same result as Divide(r, q, a, Power2(n)), but faster
static void CRYPTOPP_API DivideByPowerOf2(Integer &r, Integer &q, const Integer &a, unsigned int n);
//! greatest common divisor
static Integer CRYPTOPP_API Gcd(const Integer &a, const Integer &n);
//! \brief calculate multiplicative inverse of *this mod n
Integer InverseMod(const Integer &n) const;
//!
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
word InverseMod(word n) const;
//@}
//! \name INPUT/OUTPUT
//@{
//! \brief Extraction operator
//! \param in a reference to a std::istream
//! \param a a reference to an Integer
//! \returns a reference to a std::istream reference
friend CRYPTOPP_DLL std::istream& CRYPTOPP_API operator>>(std::istream& in, Integer &a);
//!
//! \brief Insertion operator
//! \param out a reference to a std::ostream
//! \param a a constant reference to an Integer
//! \returns a reference to a std::ostream reference
//! \details The output integer responds to std::hex, std::oct, std::hex, std::upper and
//! std::lower. The output includes the suffix \a \b h (for hex), \a \b . (\a \b dot, for dec)
//! and \a \b o (for octal). There is currently no way to suppress the suffix.
//! \details If you want to print an Integer without the suffix or using an arbitrary base, then
//! use IntToString<Integer>().
//! \sa IntToString<Integer>
friend CRYPTOPP_DLL std::ostream& CRYPTOPP_API operator<<(std::ostream& out, const Integer &a);
//@}
#ifndef CRYPTOPP_DOXYGEN_PROCESSING
//! modular multiplication
CRYPTOPP_DLL friend Integer CRYPTOPP_API a_times_b_mod_c(const Integer &x, const Integer& y, const Integer& m);
//! modular exponentiation
CRYPTOPP_DLL friend Integer CRYPTOPP_API a_exp_b_mod_c(const Integer &x, const Integer& e, const Integer& m);
#endif
private:
Integer(word value, size_t length);
int PositiveCompare(const Integer &t) const;
IntegerSecBlock reg;
Sign sign;
#ifndef CRYPTOPP_DOXYGEN_PROCESSING
friend class ModularArithmetic;
friend class MontgomeryRepresentation;
friend class HalfMontgomeryRepresentation;
friend void PositiveAdd(Integer &sum, const Integer &a, const Integer &b);
friend void PositiveSubtract(Integer &diff, const Integer &a, const Integer &b);
friend void PositiveMultiply(Integer &product, const Integer &a, const Integer &b);
friend void PositiveDivide(Integer &remainder, Integer &quotient, const Integer &dividend, const Integer &divisor);
#endif
};
//! \brief Comparison
inline bool operator==(const CryptoPP::Integer& a, const CryptoPP::Integer& b) {return a.Compare(b)==0;}
//! \brief Comparison
inline bool operator!=(const CryptoPP::Integer& a, const CryptoPP::Integer& b) {return a.Compare(b)!=0;}
//! \brief Comparison
inline bool operator> (const CryptoPP::Integer& a, const CryptoPP::Integer& b) {return a.Compare(b)> 0;}
//! \brief Comparison
inline bool operator>=(const CryptoPP::Integer& a, const CryptoPP::Integer& b) {return a.Compare(b)>=0;}
//! \brief Comparison
inline bool operator< (const CryptoPP::Integer& a, const CryptoPP::Integer& b) {return a.Compare(b)< 0;}
//! \brief Comparison
inline bool operator<=(const CryptoPP::Integer& a, const CryptoPP::Integer& b) {return a.Compare(b)<=0;}
//! \brief Addition
inline CryptoPP::Integer operator+(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.Plus(b);}
//! \brief Subtraction
inline CryptoPP::Integer operator-(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.Minus(b);}
//! \brief Multiplication
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
inline CryptoPP::Integer operator*(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.Times(b);}
//! \brief Division
inline CryptoPP::Integer operator/(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.DividedBy(b);}
//! \brief Remainder
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
inline CryptoPP::Integer operator%(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.Modulo(b);}
//! \brief Division
inline CryptoPP::Integer operator/(const CryptoPP::Integer &a, CryptoPP::word b) {return a.DividedBy(b);}
//! \brief Remainder
//! \sa a_times_b_mod_c() and a_exp_b_mod_c()
inline CryptoPP::word operator%(const CryptoPP::Integer &a, CryptoPP::word b) {return a.Modulo(b);}
//! \brief Bitwise AND
//! \param a the first Integer
//! \param b the second Integer
//! \returns the result of a & b
//! \details operator&() performs a bitwise AND on the operands. Missing bits are truncated
//! at the most significant bit positions, so the result is as small as the
//! smaller of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
inline CryptoPP::Integer operator&(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.And(b);}
//! \brief Bitwise OR
//! \param a the first Integer
//! \param b the second Integer
//! \returns the result of a | b
//! \details operator|() performs a bitwise OR on the operands. Missing bits are shifted in
//! at the most significant bit positions, so the result is as large as the
//! larger of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
inline CryptoPP::Integer operator|(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.Or(b);}
//! \brief Bitwise XOR
//! \param a the first Integer
//! \param b the second Integer
//! \returns the result of a ^ b
//! \details operator^() performs a bitwise XOR on the operands. Missing bits are shifted
//! in at the most significant bit positions, so the result is as large as the
//! larger of the operands.
//! \details Internally, Crypto++ uses a sign-magnitude representation. The library
//! does not attempt to interpret bits, and the result is always POSITIVE. If needed,
//! the integer should be converted to a 2's compliment representation before performing
//! the operation.
//! \since Crypto++ 6.0
inline CryptoPP::Integer operator^(const CryptoPP::Integer &a, const CryptoPP::Integer &b) {return a.Xor(b);}
NAMESPACE_END
#ifndef __BORLANDC__
NAMESPACE_BEGIN(std)
inline void swap(CryptoPP::Integer &a, CryptoPP::Integer &b)
{
a.swap(b);
}
NAMESPACE_END
#endif
#endif