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/*************************************************
* IF (RSA/RW) Operation Source File *
* (C) 1999-2007 Jack Lloyd *
*************************************************/
#include <botan/eng_def.h>
#include <botan/pow_mod.h>
#include <botan/numthry.h>
#include <botan/reducer.h>
namespace Botan {
namespace {
/*************************************************
* Default IF Operation *
*************************************************/
class Default_IF_Op : public IF_Operation
{
public:
BigInt public_op(const BigInt& i) const
{ return powermod_e_n(i); }
BigInt private_op(const BigInt&) const;
IF_Operation* clone() const { return new Default_IF_Op(*this); }
Default_IF_Op(const BigInt&, const BigInt&, const BigInt&,
const BigInt&, const BigInt&, const BigInt&,
const BigInt&, const BigInt&);
private:
Fixed_Exponent_Power_Mod powermod_e_n, powermod_d1_p, powermod_d2_q;
Modular_Reducer reducer;
BigInt c, q;
};
/*************************************************
* Default_IF_Op Constructor *
*************************************************/
Default_IF_Op::Default_IF_Op(const BigInt& e, const BigInt& n, const BigInt&,
const BigInt& p, const BigInt& q,
const BigInt& d1, const BigInt& d2,
const BigInt& c)
{
powermod_e_n = Fixed_Exponent_Power_Mod(e, n);
if(d1 != 0 && d2 != 0 && p != 0 && q != 0)
{
powermod_d1_p = Fixed_Exponent_Power_Mod(d1, p);
powermod_d2_q = Fixed_Exponent_Power_Mod(d2, q);
reducer = Modular_Reducer(p);
this->c = c;
this->q = q;
}
}
/*************************************************
* Default IF Private Operation *
*************************************************/
BigInt Default_IF_Op::private_op(const BigInt& i) const
{
if(q == 0)
throw Internal_Error("Default_IF_Op::private_op: No private key");
BigInt j1 = powermod_d1_p(i);
BigInt j2 = powermod_d2_q(i);
j1 = reducer.reduce(sub_mul(j1, j2, c));
return mul_add(j1, q, j2);
}
}
/*************************************************
* Acquire an IF op *
*************************************************/
IF_Operation* Default_Engine::if_op(const BigInt& e, const BigInt& n,
const BigInt& d, const BigInt& p,
const BigInt& q, const BigInt& d1,
const BigInt& d2, const BigInt& c) const
{
return new Default_IF_Op(e, n, d, p, q, d1, d2, c);
}
}
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