Botan::Modular_Reducer Class Reference

#include <reducer.h>

Public Member Functions
BigInt	cube (const BigInt &x) const
const BigInt &	get_modulus () const
bool	initialized () const
	Modular_Reducer ()
	Modular_Reducer (const BigInt &mod)
BigInt	multiply (const BigInt &x, const BigInt &y) const
BigInt	multiply (const BigInt &x, const BigInt &y, const BigInt &z) const
void	reduce (BigInt &out, const BigInt &x, secure_vector< word > &) const
BigInt	reduce (const BigInt &x) const
BigInt	square (const BigInt &x) const

Static Public Member Functions
static Modular_Reducer	for_public_modulus (const BigInt &m)
static Modular_Reducer	for_secret_modulus (const BigInt &m)

Detailed Description

Modular Reducer

This class is deprecated without replacement

Definition at line 22 of file reducer.h.

Constructor & Destructor Documentation

Modular_Reducer() [1/2]

Botan::Modular_Reducer::Modular_Reducer ( )

inline

Create an uninitialized Modular_Reducer

Definition at line 85 of file reducer.h.

: m_mod_words(0) {}

References Modular_Reducer().

Referenced by for_public_modulus(), for_secret_modulus(), and Modular_Reducer().

Modular_Reducer() [2/2]

Botan::Modular_Reducer::Modular_Reducer ( const BigInt & mod )

explicit

Accepts m == 0 and leaves the Modular_Reducer in an uninitialized state

Definition at line 15 of file reducer.cpp.

                                                  : m_mod_words(mod.sig_words()) {
   if(mod < 0) {
      throw Invalid_Argument("Modular_Reducer: modulus must be positive");
   }
 
   m_modulus = mod;
}

Member Function Documentation

cube()

BigInt Botan::Modular_Reducer::cube ( const BigInt & x ) const

inline

Cube mod p

Parameters

x	the value to cube

Returns

(x * x * x) % p

Definition at line 63 of file reducer.h.

{ return multiply(x, this->square(x)); }

References multiply(), and square().

for_public_modulus()

Modular_Reducer Botan::Modular_Reducer::for_public_modulus ( const BigInt & m )

inlinestatic

Requires that m > 0

Definition at line 95 of file reducer.h.

{ return Modular_Reducer(m); }

References Modular_Reducer().

for_secret_modulus()

Modular_Reducer Botan::Modular_Reducer::for_secret_modulus ( const BigInt & m )

inlinestatic

Requires that m > 0

Definition at line 100 of file reducer.h.

{ return Modular_Reducer(m); }

References Modular_Reducer().

get_modulus()

const BigInt & Botan::Modular_Reducer::get_modulus ( ) const

inline

Return the modulus of this reducer

Returns

the modulus

Definition at line 28 of file reducer.h.

{ return m_modulus; }

initialized()

bool Botan::Modular_Reducer::initialized ( ) const

inline

Test whether this reducer was initialized with a non-zero modulus

Returns

true if a modulus is set

Definition at line 80 of file reducer.h.

{ return (m_mod_words != 0); }

multiply() [1/2]

BigInt Botan::Modular_Reducer::multiply ( const BigInt & x, const BigInt & y ) const

inline

Multiply mod p

Parameters

x	the first operand
y	the second operand

Returns

(x * y) % p

Definition at line 43 of file reducer.h.

{ return reduce(x * y); }

References reduce().

Referenced by cube().

multiply() [2/2]

BigInt Botan::Modular_Reducer::multiply ( const BigInt & x, const BigInt & y, const BigInt & z ) const

inline

Multiply mod p

Returns

(x * y * z) % p

Definition at line 49 of file reducer.h.

{ return multiply(x, multiply(y, z)); }

References multiply().

Referenced by multiply().

reduce() [1/2]

void Botan::Modular_Reducer::reduce ( BigInt & out, const BigInt & x, secure_vector< word > &  ) const

inline

Low level reduction function. Mostly for internal use. Sometimes useful for performance by reducing temporaries Reduce x mod p and place the output in out.

Warning

X and out must not reference each other

ws is an (ignored) a temporary workspace.

Definition at line 74 of file reducer.h.

{ out = reduce(x); }

References reduce().

Referenced by reduce().

reduce() [2/2]

BigInt Botan::Modular_Reducer::reduce

(

const BigInt &

x

)

const

Reduce a value modulo p

Parameters

x	the value to reduce

Returns

(x % p)

Definition at line 23 of file reducer.cpp.

                                                    {
   return ct_modulo(x, m_modulus);
}

References Botan::ct_modulo().

Referenced by multiply(), and square().

square()

BigInt Botan::Modular_Reducer::square ( const BigInt & x ) const

inline

Square mod p

Parameters

x	the value to square

Returns

(x * x) % p

Definition at line 56 of file reducer.h.

{ return reduce(x * x); }

References reduce().

Referenced by cube().

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

• src/lib/math/numbertheory/reducer.h
• src/lib/math/numbertheory/reducer.cpp