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Merge pull request #9 from arybczak/expose-const-time-pow

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Expose const time exponentiation for fields
dev
MITSUNARI Shigeo 8 years ago committed by GitHub
parent e5d3fd9651 ba8e271ca9
commit 4e43eeabd8
1 changed files with 8 additions and 8 deletions
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  1. 16
      include/mcl/operator.hpp

16
include/mcl/operator.hpp
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@ -41,23 +41,23 @@ struct Operator : E {
friend MCL_FORCE_INLINE T operator/(const T& a, const T& b) { T c; T::inv(c, b); c *= a; return c; } friend MCL_FORCE_INLINE T operator/(const T& a, const T& b) { T c; T::inv(c, b); c *= a; return c; }
MCL_FORCE_INLINE T operator-() const { T c; T::neg(c, static_cast<const T&>(*this)); return c; } MCL_FORCE_INLINE T operator-() const { T c; T::neg(c, static_cast<const T&>(*this)); return c; }
template<class tag2, size_t maxBitSize2, template<class _tag, size_t _maxBitSize> class FpT> template<class tag2, size_t maxBitSize2, template<class _tag, size_t _maxBitSize> class FpT>
static void pow(T& z, const T& x, const FpT<tag2, maxBitSize2>& y) static void pow(T& z, const T& x, const FpT<tag2, maxBitSize2>& y, bool constTime = false)
{ {
fp::Block b; fp::Block b;
y.getBlock(b); y.getBlock(b);
powArray(z, x, b.p, b.n, false); powArray(z, x, b.p, b.n, false, constTime);
} }
static void pow(T& z, const T& x, int y) static void pow(T& z, const T& x, int y, bool constTime = false)
{ {
const Unit u = abs(y); const Unit u = abs(y);
powArray(z, x, &u, 1, y < 0); powArray(z, x, &u, 1, y < 0, constTime);
} }
static void pow(T& z, const T& x, const mpz_class& y) static void pow(T& z, const T& x, const mpz_class& y, bool constTime = false)
{ {
powArray(z, x, gmp::getUnit(y), abs(y.get_mpz_t()->_mp_size), y < 0); powArray(z, x, gmp::getUnit(y), abs(y.get_mpz_t()->_mp_size), y < 0, constTime);
} }
private: private:
static void powArray(T& z, const T& x, const Unit *y, size_t yn, bool isNegative) static void powArray(T& z, const T& x, const Unit *y, size_t yn, bool isNegative, bool constTime)
{ {
T tmp; T tmp;
const T *px = &x; const T *px = &x;
@ -66,7 +66,7 @@ private:
px = &tmp; px = &tmp;
} }
z = 1; z = 1;
fp::powGeneric(z, *px, y, yn, T::mul, T::sqr, (void (*)(T&, const T&))0); fp::powGeneric(z, *px, y, yn, T::mul, T::sqr, (void (*)(T&, const T&))0, constTime);
if (isNegative) { if (isNegative) {
T::inv(z, z); T::inv(z, z);
} }

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