Botan::Fixed_Base_Power_Mod Class Reference

#include <pow_mod.h>

Inheritance diagram for Botan::Fixed_Base_Power_Mod:

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
	Fixed_Base_Power_Mod ()
	Fixed_Base_Power_Mod (const BigInt &, const BigInt &, Usage_Hints=NO_HINTS)
BigInt	operator() (const BigInt &e) const
void	set_base (const BigInt &) const
void	set_exponent (const BigInt &) const
void	set_modulus (const BigInt &, Usage_Hints=NO_HINTS) const

Static Public Member Functions
static size_t	window_bits (size_t exp_bits, size_t base_bits, Power_Mod::Usage_Hints hints)

Detailed Description

Fixed Base Modular Exponentiator Proxy

Definition at line 87 of file pow_mod.h.

Member Enumeration Documentation

Usage_Hints

enum Botan::Power_Mod::Usage_Hints

inherited

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
      };

Constructor & Destructor Documentation

Fixed_Base_Power_Mod() [1/2]

Botan::Fixed_Base_Power_Mod::Fixed_Base_Power_Mod ( )

inline

Definition at line 93 of file pow_mod.h.

{}

Referenced by Botan::DSA_Verification_Operation::DSA_Verification_Operation(), Botan::ElGamal_Encryption_Operation::ElGamal_Encryption_Operation(), and Botan::NR_Verification_Operation::NR_Verification_Operation().

Fixed_Base_Power_Mod() [2/2]

Botan::Fixed_Base_Power_Mod::Fixed_Base_Power_Mod	(	const BigInt &	b,
		const BigInt &	n,
		Usage_Hints	hints = NO_HINTS )

Definition at line 206 of file pow_mod.cpp.

                                                              :
   Power_Mod(n, Usage_Hints(hints | BASE_IS_FIXED | choose_base_hints(b, n)))
   {
   set_base(b);
   }

References Botan::Power_Mod::BASE_IS_FIXED, Botan::Power_Mod::Power_Mod(), and Botan::Power_Mod::set_base().

Member Function Documentation

execute()

BigInt Botan::Power_Mod::execute ( ) const

inherited

Definition at line 109 of file pow_mod.cpp.

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

References Botan::Internal_Error::Internal_Error().

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

operator()()

BigInt Botan::Fixed_Base_Power_Mod::operator() ( const BigInt & e ) const

inline

Definition at line 90 of file pow_mod.h.

         { set_exponent(e); return execute(); }

References Botan::Power_Mod::execute(), and Botan::Power_Mod::set_exponent().

set_base()

void Botan::Power_Mod::set_base ( const BigInt & b ) const

inherited

Definition at line 83 of file pow_mod.cpp.

   {
   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);
   }

References Botan::Internal_Error::Internal_Error(), Botan::BigInt::is_negative(), and Botan::BigInt::is_zero().

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

set_exponent()

void Botan::Power_Mod::set_exponent ( const BigInt & e ) const

inherited

Definition at line 96 of file pow_mod.cpp.

   {
   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);
   }

References Botan::Internal_Error::Internal_Error(), and Botan::BigInt::is_negative().

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

set_modulus()

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

inherited

Definition at line 58 of file pow_mod.cpp.

   {
   delete core;
   core = 0;
 
   if(n != 0)
      {
      Algorithm_Factory::Engine_Iterator i(global_state().algorithm_factory());
 
      while(const Engine* engine = i.next())
         {
         core = engine->mod_exp(n, hints);
 
         if(core)
            break;
         }
 
      if(!core)
         throw Lookup_Error("Power_Mod: Unable to find a working engine");
      }
   }

References Botan::global_state(), Botan::Lookup_Error::Lookup_Error(), and Botan::Algorithm_Factory::Engine_Iterator::next().

Referenced by Power_Mod().

window_bits()

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

staticinherited

Definition at line 119 of file pow_mod.cpp.

   {
   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;
   }

References BASE_IS_FIXED, EXP_IS_LARGE, and window_bits().

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

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

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