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| author | Jeffrey Walton <noloader@gmail.com> | 2019-08-07 02:43:13 -0400 |
|---|---|---|
| committer | Jeffrey Walton <noloader@gmail.com> | 2019-08-07 02:43:13 -0400 |
| commit | f3dd3d25592ceb688d2b32475f72118222869516 (patch) | |
| tree | 7b6d9895681132df4a509a9951c9bf67186b4952 /ecp.cpp | |
| parent | b5fe6ab3833bf506b1c0caf8400d7a4e2cc8b688 (diff) | |
| download | cryptopp-git-f3dd3d25592ceb688d2b32475f72118222869516.tar.gz | |
Avoid temporary ECP::Point in ECP Addition and Double
This regains a lot of performance lost to the const-timeness (GH #869)
Diffstat (limited to 'ecp.cpp')
| -rw-r--r-- | ecp.cpp | 54 |
1 files changed, 36 insertions, 18 deletions
@@ -527,6 +527,7 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P) const {
const ECP::Field& field = m_ecp.GetField();
const FieldElement& b = m_ecp.m_b;
+ ECP::Point& R = m_ecp.m_R;
// Gyrations attempt to maintain constant-timeness
// We need either (P.x, P.y, 1) or (0, 1, 0).
@@ -575,14 +576,17 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P) const X3 = field.Multiply(X3, inv); Y3 = field.Multiply(Y3, inv);
// More gyrations
- ECP::Point result(X3*Z3.NotZero(), Y3*Z3.NotZero());
- result.identity = Z3.IsZero();
- return result;
+ R.x = X3*Z3.NotZero();
+ R.y = Y3*Z3.NotZero();
+ R.identity = Z3.IsZero();
+
+ return R;
}
else if (m_alpha == A_0)
{
const ECP::Field& field = m_ecp.GetField();
const FieldElement b3 = field.Multiply(m_ecp.m_b, 3);
+ ECP::Point& R = m_ecp.m_R;
// Gyrations attempt to maintain constant-timeness
// We need either (P.x, P.y, 1) or (0, 1, 0).
@@ -615,14 +619,17 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P) const X3 = field.Multiply(X3, inv); Y3 = field.Multiply(Y3, inv);
// More gyrations
- ECP::Point result(X3*Z3.NotZero(), Y3*Z3.NotZero());
- result.identity = Z3.IsZero();
- return result;
+ R.x = X3*Z3.NotZero();
+ R.y = Y3*Z3.NotZero();
+ R.identity = Z3.IsZero();
+
+ return R;
}
else if (m_alpha == A_Star)
{
const ECP::Field& field = m_ecp.GetField();
const FieldElement b3 = field.Multiply(m_ecp.m_b, 3);
+ ECP::Point& R = m_ecp.m_R;
// Gyrations attempt to maintain constant-timeness
// We need either (P.x, P.y, 1) or (0, 1, 0).
@@ -655,9 +662,11 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P) const X3 = field.Multiply(X3, inv); Y3 = field.Multiply(Y3, inv);
// More gyrations
- ECP::Point result(X3*Z3.NotZero(), Y3*Z3.NotZero());
- result.identity = Z3.IsZero();
- return result;
+ R.x = X3*Z3.NotZero();
+ R.y = Y3*Z3.NotZero();
+ R.identity = Z3.IsZero();
+
+ return R;
}
else // A_Montgomery
{
@@ -690,6 +699,7 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P, const Point& Q) con {
const ECP::Field& field = m_ecp.GetField();
const FieldElement& b = m_ecp.m_b;
+ ECP::Point& R = m_ecp.m_R;
// Gyrations attempt to maintain constant-timeness
// We need either (P.x, P.y, 1) or (0, 1, 0).
@@ -751,14 +761,17 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P, const Point& Q) con X3 = field.Multiply(X3, inv); Y3 = field.Multiply(Y3, inv);
// More gyrations
- ECP::Point result(X3*Z3.NotZero(), Y3*Z3.NotZero());
- result.identity = Z3.IsZero();
- return result;
+ R.x = X3*Z3.NotZero();
+ R.y = Y3*Z3.NotZero();
+ R.identity = Z3.IsZero();
+
+ return R;
}
else if (m_alpha == A_0)
{
const ECP::Field& field = m_ecp.GetField();
const FieldElement b3 = field.Multiply(m_ecp.m_b, 3);
+ ECP::Point& R = m_ecp.m_R;
// Gyrations attempt to maintain constant-timeness
// We need either (P.x, P.y, 1) or (0, 1, 0).
@@ -795,15 +808,18 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P, const Point& Q) con X3 = field.Multiply(X3, inv); Y3 = field.Multiply(Y3, inv);
// More gyrations
- ECP::Point result(X3*Z3.NotZero(), Y3*Z3.NotZero());
- result.identity = Z3.IsZero();
- return result;
+ R.x = X3*Z3.NotZero();
+ R.y = Y3*Z3.NotZero();
+ R.identity = Z3.IsZero();
+
+ return R;
}
else if (m_alpha == A_Star)
{
const ECP::Field& field = m_ecp.GetField();
const FieldElement &a = m_ecp.m_a;
const FieldElement b3 = field.Multiply(m_ecp.m_b, 3);
+ ECP::Point& R = m_ecp.m_R;
// Gyrations attempt to maintain constant-timeness
// We need either (P.x, P.y, 1) or (0, 1, 0).
@@ -862,9 +878,11 @@ ECP::Point ECP::AdditionFunction::operator()(const Point& P, const Point& Q) con X3 = field.Multiply(X3, inv); Y3 = field.Multiply(Y3, inv);
// More gyrations
- ECP::Point result(X3*Z3.NotZero(), Y3*Z3.NotZero());
- result.identity = Z3.IsZero();
- return result;
+ R.x = X3*Z3.NotZero();
+ R.y = Y3*Z3.NotZero();
+ R.identity = Z3.IsZero();
+
+ return R;
}
else // A_Montgomery
{
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