Botan::Power_Mod Class Reference

#include <pow_mod.h>

Inheritance diagram for Botan::Power_Mod:

List of all members.

Public Types
enum	Usage_Hints {   NO_HINTS = 0x0000, BASE_IS_FIXED = 0x0001, BASE_IS_SMALL = 0x0002, BASE_IS_LARGE = 0x0004,   BASE_IS_2 = 0x0008, EXP_IS_FIXED = 0x0100, EXP_IS_SMALL = 0x0200, EXP_IS_LARGE = 0x0400 }
Public Member Functions
BigInt	execute () const
Power_Mod &	operator= (const Power_Mod &)
	Power_Mod (const BigInt &=0, Usage_Hints=NO_HINTS)
	Power_Mod (const Power_Mod &)
void	set_base (const BigInt &) const
void	set_exponent (const BigInt &) const
void	set_modulus (const BigInt &, Usage_Hints=NO_HINTS) const
virtual	~Power_Mod ()
Static Public Member Functions
static size_t	window_bits (size_t exp_bits, size_t base_bits, Power_Mod::Usage_Hints hints)

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Detailed Description

Modular Exponentiator Proxy

Definition at line 31 of file pow_mod.h.

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Member Enumeration Documentation

enum Botan::Power_Mod::Usage_Hints

Enumerator:

NO_HINTS
BASE_IS_FIXED
BASE_IS_SMALL
BASE_IS_LARGE
BASE_IS_2
EXP_IS_FIXED
EXP_IS_SMALL
EXP_IS_LARGE

Definition at line 35 of file pow_mod.h.

                       {
         NO_HINTS        = 0x0000,

         BASE_IS_FIXED   = 0x0001,
         BASE_IS_SMALL   = 0x0002,
         BASE_IS_LARGE   = 0x0004,
         BASE_IS_2       = 0x0008,

         EXP_IS_FIXED    = 0x0100,
         EXP_IS_SMALL    = 0x0200,
         EXP_IS_LARGE    = 0x0400
      };

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Constructor & Destructor Documentation

Botan::Power_Mod::Power_Mod	(	const BigInt &	n = 0,
		Usage_Hints	hints = NO_HINTS
	)

Definition at line 16 of file pow_mod.cpp.

References set_modulus().

   {
   core = nullptr;
   set_modulus(n, hints);
   }

Botan::Power_Mod::Power_Mod

(

const Power_Mod &

other

)

Definition at line 25 of file pow_mod.cpp.

References Botan::Modular_Exponentiator::copy().

   {
   core = nullptr;
   if(other.core)
      core = other.core->copy();
   }

Botan::Power_Mod::~Power_Mod

(

)

[virtual]

Definition at line 47 of file pow_mod.cpp.

   {
   delete core;
   core = nullptr;
   }

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Member Function Documentation

BigInt Botan::Power_Mod::execute

(

)

const

Definition at line 95 of file pow_mod.cpp.

References Botan::Modular_Exponentiator::execute().

Referenced by Botan::power_mod().

   {
   if(!core)
      throw Internal_Error("Power_Mod::execute: core was NULL");
   return core->execute();
   }

Power_Mod & Botan::Power_Mod::operator=

(

const Power_Mod &

other

)

Definition at line 35 of file pow_mod.cpp.

References Botan::Modular_Exponentiator::copy().

   {
   delete core;
   core = nullptr;
   if(other.core)
      core = other.core->copy();
   return (*this);
   }

void Botan::Power_Mod::set_base

(

const BigInt &

b

)

const

Definition at line 69 of file pow_mod.cpp.

References Botan::BigInt::is_negative(), Botan::BigInt::is_zero(), and Botan::Modular_Exponentiator::set_base().

Referenced by Botan::Fixed_Base_Power_Mod::Fixed_Base_Power_Mod(), and Botan::power_mod().

   {
   if(b.is_zero() || b.is_negative())
      throw Invalid_Argument("Power_Mod::set_base: arg must be > 0");

   if(!core)
      throw Internal_Error("Power_Mod::set_base: core was NULL");
   core->set_base(b);
   }

void Botan::Power_Mod::set_exponent

(

const BigInt &

e

)

const

Definition at line 82 of file pow_mod.cpp.

References Botan::BigInt::is_negative(), and Botan::Modular_Exponentiator::set_exponent().

Referenced by Botan::Fixed_Exponent_Power_Mod::Fixed_Exponent_Power_Mod(), and Botan::power_mod().

   {
   if(e.is_negative())
      throw Invalid_Argument("Power_Mod::set_exponent: arg must be > 0");

   if(!core)
      throw Internal_Error("Power_Mod::set_exponent: core was NULL");
   core->set_exponent(e);
   }

void Botan::Power_Mod::set_modulus	(	const BigInt &	n,
		Usage_Hints	hints = NO_HINTS
	)		const

Definition at line 56 of file pow_mod.cpp.

References Botan::BigInt::is_odd().

Referenced by Power_Mod().

   {
   delete core;

   if(n.is_odd())
      core = new Montgomery_Exponentiator(n, hints);
   else if(n != 0)
      core = new Fixed_Window_Exponentiator(n, hints);
   }

size_t Botan::Power_Mod::window_bits	(	size_t	exp_bits,
		size_t	base_bits,
		Power_Mod::Usage_Hints	hints
	)		[static]

Definition at line 105 of file pow_mod.cpp.

References BASE_IS_FIXED, and EXP_IS_LARGE.

Referenced by Botan::Fixed_Window_Exponentiator::set_base(), and Botan::Montgomery_Exponentiator::set_base().

   {
   static const size_t wsize[][2] = {
      { 1434, 7 },
      {  539, 6 },
      {  197, 4 },
      {   70, 3 },
      {   25, 2 },
      {    0, 0 }
   };

   size_t window_bits = 1;

   if(exp_bits)
      {
      for(size_t j = 0; wsize[j][0]; ++j)
         {
         if(exp_bits >= wsize[j][0])
            {
            window_bits += wsize[j][1];
            break;
            }
         }
      }

   if(hints & Power_Mod::BASE_IS_FIXED)
      window_bits += 2;
   if(hints & Power_Mod::EXP_IS_LARGE)
      ++window_bits;

   return window_bits;
   }

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

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