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/******************************************************
* Elliptic curves over GF(p) (source file) *
* *
* (C) 2007 Martin Doering *
* doering@cdc.informatik.tu-darmstadt.de *
* Christoph Ludwig *
* ludwig@fh-worms.de *
* Falko Strenzke *
* strenzke@flexsecure.de *
******************************************************/
#include <botan/curve_gfp.h>
namespace Botan {
CurveGFp::CurveGFp(GFpElement const& a, GFpElement const& b,
const BigInt& p) :
mA(a), mB(b)
{
if(p != mA.get_p() || p != mB.get_p())
throw Invalid_Argument("could not construct curve: moduli of arguments differ");
std::tr1::shared_ptr<GFpModulus> p_mod = std::tr1::shared_ptr<GFpModulus>(new GFpModulus(p));
// the above is the creation of the GFpModuls object which will be shared point-wide
// (in the context of a point of course)
set_shrd_mod(p_mod);
}
// copy constructor
CurveGFp::CurveGFp(CurveGFp const& other)
: mA(other.get_a()),
mB(other.get_b())
{
mp_mod = std::tr1::shared_ptr<GFpModulus>(new GFpModulus(*other.mp_mod));
//assert(mp_mod->p_equal_to(mA.get_p()));
//assert(mp_mod->p_equal_to(mB.get_p()));
set_shrd_mod(mp_mod);
if(other.mp_mres_a.get())
{
mp_mres_a = std::tr1::shared_ptr<GFpElement>(new GFpElement(*other.mp_mres_a));
}
if(other.mp_mres_b.get())
{
mp_mres_b = std::tr1::shared_ptr<GFpElement>(new GFpElement(*other.mp_mres_b));
}
if(other.mp_mres_one.get())
{
mp_mres_one = std::tr1::shared_ptr<GFpElement>(new GFpElement(*other.mp_mres_one));
}
}
// assignment operator
CurveGFp const& CurveGFp::operator=(CurveGFp const& other)
{
// for exception safety...
GFpElement a_tmp = other.mA;
GFpElement b_tmp = other.mB;
mA.swap(a_tmp);
mB.swap(b_tmp);
std::tr1::shared_ptr<GFpModulus> p_mod = std::tr1::shared_ptr<GFpModulus>(new GFpModulus(*other.mp_mod));
set_shrd_mod(p_mod);
// exception safety note: no problem if we have a throw from here on...
if(other.mp_mres_a.get())
{
mp_mres_a = std::tr1::shared_ptr<GFpElement>(new GFpElement(*other.mp_mres_a));
}
if(other.mp_mres_b.get())
{
mp_mres_b = std::tr1::shared_ptr<GFpElement>(new GFpElement(*other.mp_mres_b));
}
if(other.mp_mres_one.get())
{
mp_mres_one = std::tr1::shared_ptr<GFpElement>(new GFpElement(*other.mp_mres_one));
}
return *this;
}
// getters
GFpElement const CurveGFp::get_a() const
{
return mA;
}
GFpElement const CurveGFp::get_b() const
{
return mB;
}
BigInt const CurveGFp::get_p() const
{
//assert(mp_mod.get() != 0);
return mp_mod->get_p();
}
// swaps the states of *this and other, does not throw
void CurveGFp::swap(CurveGFp& other)
{
mA.swap(other.mA);
mB.swap(other.mB);
mp_mod.swap(other.mp_mod);
std::swap(mp_mres_a, other.mp_mres_a);
std::swap(mp_mres_b, other.mp_mres_b);
std::swap(mp_mres_one, other.mp_mres_one);
}
void CurveGFp::set_shrd_mod(std::tr1::shared_ptr<GFpModulus> const mod)
{
mp_mod = mod;
mA.turn_off_sp_red_mul();// m.m. is not needed, must be trf. back
mB.turn_off_sp_red_mul();// m.m. is not needed, must be trf. back
//ok, above we destroy any evantually computated montg. mult. values,
// but that won't influence performance in usual applications
mA.set_shrd_mod(mod);
mB.set_shrd_mod(mod);
}
GFpElement const CurveGFp::get_mres_a() const
{
if(mp_mres_a.get() == 0)
{
mp_mres_a = std::tr1::shared_ptr<GFpElement>(new GFpElement(mA));
mp_mres_a->turn_on_sp_red_mul();
mp_mres_a->get_mres();
}
return GFpElement(*mp_mres_a);
}
GFpElement const CurveGFp::get_mres_b() const
{
if(mp_mres_b.get() == 0)
{
mp_mres_b = std::tr1::shared_ptr<GFpElement>(new GFpElement(mB));
mp_mres_b->turn_on_sp_red_mul();
mp_mres_b->get_mres();
}
return GFpElement(*mp_mres_b);
}
std::tr1::shared_ptr<GFpElement const> const CurveGFp::get_mres_one() const
{
if(mp_mres_one.get() == 0)
{
mp_mres_one = std::tr1::shared_ptr<GFpElement>(new GFpElement(mp_mod->get_p(), 1));
mp_mres_one->turn_on_sp_red_mul();
mp_mres_one->get_mres();
}
return mp_mres_one;
}
bool operator==(CurveGFp const& lhs, CurveGFp const& rhs)
{
return (lhs.get_p() == rhs.get_p() && lhs.get_a() == rhs.get_a() && lhs.get_b() == rhs.get_b());
}
}
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