diff options
Diffstat (limited to 'src/math/numbertheory/pow_mod.cpp')
| -rw-r--r-- | src/math/numbertheory/pow_mod.cpp | 211 |
1 files changed, 0 insertions, 211 deletions
diff --git a/src/math/numbertheory/pow_mod.cpp b/src/math/numbertheory/pow_mod.cpp deleted file mode 100644 index c7d7fe70e..000000000 --- a/src/math/numbertheory/pow_mod.cpp +++ /dev/null @@ -1,211 +0,0 @@ -/* -* Modular Exponentiation Proxy -* (C) 1999-2007 Jack Lloyd -* -* Distributed under the terms of the Botan license -*/ - -#include <botan/pow_mod.h> -#include <botan/libstate.h> -#include <botan/engine.h> - -namespace Botan { - -/* -* Power_Mod Constructor -*/ -Power_Mod::Power_Mod(const BigInt& n, Usage_Hints hints) - { - core = nullptr; - set_modulus(n, hints); - } - -/* -* Power_Mod Copy Constructor -*/ -Power_Mod::Power_Mod(const Power_Mod& other) - { - core = nullptr; - if(other.core) - core = other.core->copy(); - } - -/* -* Power_Mod Assignment Operator -*/ -Power_Mod& Power_Mod::operator=(const Power_Mod& other) - { - delete core; - core = nullptr; - if(other.core) - core = other.core->copy(); - return (*this); - } - -/* -* Power_Mod Destructor -*/ -Power_Mod::~Power_Mod() - { - delete core; - } - -/* -* Set the modulus -*/ -void Power_Mod::set_modulus(const BigInt& n, Usage_Hints hints) const - { - delete core; - core = nullptr; - - 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"); - } - } - -/* -* Set the base -*/ -void Power_Mod::set_base(const BigInt& b) const - { - 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); - } - -/* -* Set the exponent -*/ -void Power_Mod::set_exponent(const BigInt& e) const - { - 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); - } - -/* -* Compute the result -*/ -BigInt Power_Mod::execute() const - { - if(!core) - throw Internal_Error("Power_Mod::execute: core was NULL"); - return core->execute(); - } - -/* -* Try to choose a good window size -*/ -size_t Power_Mod::window_bits(size_t exp_bits, size_t, - Power_Mod::Usage_Hints hints) - { - 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; - } - -namespace { - -/* -* Choose potentially useful hints -*/ -Power_Mod::Usage_Hints choose_base_hints(const BigInt& b, const BigInt& n) - { - if(b == 2) - return Power_Mod::Usage_Hints(Power_Mod::BASE_IS_2 | - Power_Mod::BASE_IS_SMALL); - - const size_t b_bits = b.bits(); - const size_t n_bits = n.bits(); - - if(b_bits < n_bits / 32) - return Power_Mod::BASE_IS_SMALL; - if(b_bits > n_bits / 4) - return Power_Mod::BASE_IS_LARGE; - - return Power_Mod::NO_HINTS; - } - -/* -* Choose potentially useful hints -*/ -Power_Mod::Usage_Hints choose_exp_hints(const BigInt& e, const BigInt& n) - { - const size_t e_bits = e.bits(); - const size_t n_bits = n.bits(); - - if(e_bits < n_bits / 32) - return Power_Mod::BASE_IS_SMALL; - if(e_bits > n_bits / 4) - return Power_Mod::BASE_IS_LARGE; - return Power_Mod::NO_HINTS; - } - -} - -/* -* Fixed_Exponent_Power_Mod Constructor -*/ -Fixed_Exponent_Power_Mod::Fixed_Exponent_Power_Mod(const BigInt& e, - const BigInt& n, - Usage_Hints hints) : - Power_Mod(n, Usage_Hints(hints | EXP_IS_FIXED | choose_exp_hints(e, n))) - { - set_exponent(e); - } - -/* -* Fixed_Base_Power_Mod Constructor -*/ -Fixed_Base_Power_Mod::Fixed_Base_Power_Mod(const BigInt& b, const BigInt& n, - Usage_Hints hints) : - Power_Mod(n, Usage_Hints(hints | BASE_IS_FIXED | choose_base_hints(b, n))) - { - set_base(b); - } - -} |