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path: root/src/lib/pubkey/ec_group/point_gfp.cpp
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-rw-r--r--src/lib/pubkey/ec_group/point_gfp.cpp154
1 files changed, 62 insertions, 92 deletions
diff --git a/src/lib/pubkey/ec_group/point_gfp.cpp b/src/lib/pubkey/ec_group/point_gfp.cpp
index c65b4ac16..8f53bb079 100644
--- a/src/lib/pubkey/ec_group/point_gfp.cpp
+++ b/src/lib/pubkey/ec_group/point_gfp.cpp
@@ -17,20 +17,17 @@ namespace Botan {
PointGFp::PointGFp(const CurveGFp& curve) :
m_curve(curve),
m_coord_x(0),
- m_coord_y(1),
+ m_coord_y(curve.get_1_rep()),
m_coord_z(0)
{
- secure_vector<word> monty_ws(m_curve.get_ws_size());
- m_curve.to_rep(m_coord_x, monty_ws);
- m_curve.to_rep(m_coord_y, monty_ws);
- m_curve.to_rep(m_coord_z, monty_ws);
+ // Assumes Montgomery rep of zero is zero
}
PointGFp::PointGFp(const CurveGFp& curve, const BigInt& x, const BigInt& y) :
m_curve(curve),
m_coord_x(x),
m_coord_y(y),
- m_coord_z(1)
+ m_coord_z(m_curve.get_1_rep())
{
if(x <= 0 || x >= curve.get_p())
throw Invalid_Argument("Invalid PointGFp affine x");
@@ -40,7 +37,6 @@ PointGFp::PointGFp(const CurveGFp& curve, const BigInt& x, const BigInt& y) :
secure_vector<word> monty_ws(m_curve.get_ws_size());
m_curve.to_rep(m_coord_x, monty_ws);
m_curve.to_rep(m_coord_y, monty_ws);
- m_curve.to_rep(m_coord_z, monty_ws);
}
void PointGFp::randomize_repr(RandomNumberGenerator& rng)
@@ -118,12 +114,13 @@ void PointGFp::add_affine(const word x_words[], size_t x_size,
resize_ws(ws_bn, m_curve.get_ws_size());
secure_vector<word>& ws = ws_bn[0].get_word_vector();
+ secure_vector<word>& sub_ws = ws_bn[1].get_word_vector();
- BigInt& T0 = ws_bn[1];
- BigInt& T1 = ws_bn[2];
- BigInt& T2 = ws_bn[3];
- BigInt& T3 = ws_bn[4];
- BigInt& T4 = ws_bn[5];
+ BigInt& T0 = ws_bn[2];
+ BigInt& T1 = ws_bn[3];
+ BigInt& T2 = ws_bn[4];
+ BigInt& T3 = ws_bn[5];
+ BigInt& T4 = ws_bn[6];
/*
https://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-3.html#addition-add-1998-cmo-2
@@ -138,13 +135,9 @@ void PointGFp::add_affine(const word x_words[], size_t x_size,
m_curve.mul(T2, m_coord_z, T3, ws); // z1^3
m_curve.mul(T0, y_words, y_size, T2, ws); // y2*z1^3
- T4 -= m_coord_x; // x2*z1^2 - x1*z2^2
- if(T4.is_negative())
- T4 += p;
+ T4.mod_sub(m_coord_x, p, sub_ws); // x2*z1^2 - x1*z2^2
- T0 -= m_coord_y;
- if(T0.is_negative())
- T0 += p;
+ T0.mod_sub(m_coord_y, p, sub_ws);
if(T4.is_zero())
{
@@ -156,7 +149,7 @@ void PointGFp::add_affine(const word x_words[], size_t x_size,
// setting to zero:
m_coord_x = 0;
- m_coord_y = 1;
+ m_coord_y = m_curve.get_1_rep();
m_coord_z = 0;
return;
}
@@ -168,22 +161,16 @@ void PointGFp::add_affine(const word x_words[], size_t x_size,
m_curve.mul(T1, T2, T4, ws);
m_curve.sqr(m_coord_x, T0, ws);
- m_coord_x -= T1;
- m_coord_x -= T3;
- m_coord_x -= T3;
- while(m_coord_x.is_negative())
- m_coord_x += p;
+ m_coord_x.mod_sub(T1, p, sub_ws);
+ m_coord_x.mod_sub(T3, p, sub_ws);
+ m_coord_x.mod_sub(T3, p, sub_ws);
- T3 -= m_coord_x;
- if(T3.is_negative())
- T3 += p;
+ T3.mod_sub(m_coord_x, p, sub_ws);
T2 = m_coord_y;
m_curve.mul(T2, T0, T3, ws);
m_curve.mul(T3, m_coord_y, T1, ws);
- T2 -= T3;
- if(T2.is_negative())
- T2 += p;
+ T2.mod_sub(T3, p, sub_ws);
m_coord_y = T2;
m_curve.mul(T3, m_coord_z, T4, ws);
@@ -207,13 +194,14 @@ void PointGFp::add(const PointGFp& rhs, std::vector<BigInt>& ws_bn)
resize_ws(ws_bn, m_curve.get_ws_size());
secure_vector<word>& ws = ws_bn[0].get_word_vector();
+ secure_vector<word>& sub_ws = ws_bn[1].get_word_vector();
- BigInt& T0 = ws_bn[1];
- BigInt& T1 = ws_bn[2];
- BigInt& T2 = ws_bn[3];
- BigInt& T3 = ws_bn[4];
- BigInt& T4 = ws_bn[5];
- BigInt& T5 = ws_bn[6];
+ BigInt& T0 = ws_bn[2];
+ BigInt& T1 = ws_bn[3];
+ BigInt& T2 = ws_bn[4];
+ BigInt& T3 = ws_bn[5];
+ BigInt& T4 = ws_bn[6];
+ BigInt& T5 = ws_bn[7];
/*
https://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-3.html#addition-add-1998-cmo-2
@@ -232,18 +220,13 @@ void PointGFp::add(const PointGFp& rhs, std::vector<BigInt>& ws_bn)
m_curve.mul(T5, m_coord_z, T3, ws); // z1^3
m_curve.mul(T0, rhs.m_coord_y, T5, ws); // y2*z1^3
- T4 -= T1; // x2*z1^2 - x1*z2^2
- if(T4.is_negative())
- T4 += p;
+ T4.mod_sub(T1, p, sub_ws); // x2*z1^2 - x1*z2^2
- T3 = T0;
- T3 -= T2;
- if(T3.is_negative())
- T3 += p;
+ T0.mod_sub(T2, p, sub_ws);
if(T4.is_zero())
{
- if(T3.is_zero())
+ if(T0.is_zero())
{
mult2(ws_bn);
return;
@@ -251,36 +234,31 @@ void PointGFp::add(const PointGFp& rhs, std::vector<BigInt>& ws_bn)
// setting to zero:
m_coord_x = 0;
- m_coord_y = 1;
+ m_coord_y = m_curve.get_1_rep();
m_coord_z = 0;
return;
}
m_curve.sqr(T5, T4, ws);
- m_curve.mul(T0, T1, T5, ws);
+ m_curve.mul(T3, T1, T5, ws);
m_curve.mul(T1, T5, T4, ws);
- m_curve.sqr(m_coord_x, T3, ws);
- m_coord_x -= T1;
- m_coord_x -= T0;
- m_coord_x -= T0;
- while(m_coord_x.is_negative())
- m_coord_x += p;
-
- T0 -= m_coord_x;
- if(T0.is_negative())
- T0 += p;
-
- m_curve.mul(m_coord_y, T3, T0, ws);
- m_curve.mul(T0, T2, T1, ws);
- m_coord_y -= T0;
- if(m_coord_y.is_negative())
- m_coord_y += p;
-
- m_curve.mul(T0, m_coord_z, rhs.m_coord_z, ws);
- m_curve.mul(m_coord_z, T0, T4, ws);
+ m_curve.sqr(m_coord_x, T0, ws);
+ m_coord_x.mod_sub(T1, p, sub_ws);
+ m_coord_x.mod_sub(T3, p, sub_ws);
+ m_coord_x.mod_sub(T3, p, sub_ws);
+
+ T3.mod_sub(m_coord_x, p, sub_ws);
+
+ m_curve.mul(m_coord_y, T0, T3, ws);
+ m_curve.mul(T3, T2, T1, ws);
+
+ m_coord_y.mod_sub(T3, p, sub_ws);
+
+ m_curve.mul(T3, m_coord_z, rhs.m_coord_z, ws);
+ m_curve.mul(m_coord_z, T3, T4, ws);
}
void PointGFp::mult2i(size_t iterations, std::vector<BigInt>& ws_bn)
@@ -317,11 +295,13 @@ void PointGFp::mult2(std::vector<BigInt>& ws_bn)
resize_ws(ws_bn, m_curve.get_ws_size());
secure_vector<word>& ws = ws_bn[0].get_word_vector();
- BigInt& T0 = ws_bn[1];
- BigInt& T1 = ws_bn[2];
- BigInt& T2 = ws_bn[3];
- BigInt& T3 = ws_bn[4];
- BigInt& T4 = ws_bn[5];
+ secure_vector<word>& sub_ws = ws_bn[1].get_word_vector();
+
+ BigInt& T0 = ws_bn[2];
+ BigInt& T1 = ws_bn[3];
+ BigInt& T2 = ws_bn[4];
+ BigInt& T3 = ws_bn[5];
+ BigInt& T4 = ws_bn[6];
/*
https://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-3.html#doubling-dbl-1986-cc
@@ -332,14 +312,14 @@ void PointGFp::mult2(std::vector<BigInt>& ws_bn)
m_curve.mul(T1, m_coord_x, T0, ws);
T1 <<= 2; // * 4
- T1.reduce_below(p, T3.get_word_vector());
+ T1.reduce_below(p, sub_ws);
if(m_curve.a_is_zero())
{
// if a == 0 then 3*x^2 + a*z^4 is just 3*x^2
m_curve.sqr(T4, m_coord_x, ws); // x^2
T4 *= 3; // 3*x^2
- T4.reduce_below(p, T3.get_word_vector());
+ T4.reduce_below(p, sub_ws);
}
else if(m_curve.a_is_minus_3())
{
@@ -351,18 +331,15 @@ void PointGFp::mult2(std::vector<BigInt>& ws_bn)
// (x-z^2)
T2 = m_coord_x;
- T2 -= T3;
- if(T2.is_negative())
- T2 += p;
+ T2.mod_sub(T3, p, sub_ws);
// (x+z^2)
- T3 += m_coord_x;
- T3.reduce_below(p, T4.get_word_vector());
+ T3.mod_add(m_coord_x, p, sub_ws);
m_curve.mul(T4, T2, T3, ws); // (x-z^2)*(x+z^2)
T4 *= 3; // 3*(x-z^2)*(x+z^2)
- T4.reduce_below(p, T3.get_word_vector());
+ T4.reduce_below(p, sub_ws);
}
else
{
@@ -372,34 +349,27 @@ void PointGFp::mult2(std::vector<BigInt>& ws_bn)
m_curve.sqr(T4, m_coord_x, ws); // x^2
T4 *= 3; // 3*x^2
- T4 += T3; // 3*x^2 + a*z^4
- T4.reduce_below(p, T3.get_word_vector());
+ T4.mod_add(T3, p, sub_ws); // 3*x^2 + a*z^4
}
m_curve.sqr(T2, T4, ws);
- T2 -= T1;
- T2 -= T1;
- while(T2.is_negative())
- T2 += p;
+ T2.mod_sub(T1, p, sub_ws);
+ T2.mod_sub(T1, p, sub_ws);
m_curve.sqr(T3, T0, ws);
T3 <<= 3;
- T3.reduce_below(p, T0.get_word_vector());
+ T3.reduce_below(p, sub_ws);
- T1 -= T2;
- while(T1.is_negative())
- T1 += p;
+ T1.mod_sub(T2, p, sub_ws);
m_curve.mul(T0, T4, T1, ws);
- T0 -= T3;
- if(T0.is_negative())
- T0 += p;
+ T0.mod_sub(T3, p, sub_ws);
m_coord_x = T2;
m_curve.mul(T2, m_coord_y, m_coord_z, ws);
T2 <<= 1;
- T2.reduce_below(p, T3.get_word_vector());
+ T2.reduce_below(p, sub_ws);
m_coord_y = T0;
m_coord_z = T2;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 11:39:58 +0000