diff options
| -rw-r--r-- | src/math/numbertheory/curve_gfp.h | 9 | ||||
| -rw-r--r-- | src/math/numbertheory/point_gfp.cpp | 2 |
2 files changed, 9 insertions, 2 deletions
diff --git a/src/math/numbertheory/curve_gfp.h b/src/math/numbertheory/curve_gfp.h index 68f07a331..a7be8987c 100644 --- a/src/math/numbertheory/curve_gfp.h +++ b/src/math/numbertheory/curve_gfp.h @@ -42,6 +42,8 @@ class BOTAN_DLL CurveGFp r_inv = inverse_mod(r, p); p_dash = (((r * r_inv) - 1) / p).word_at(0); + + a_r = reducer_p.multiply(a, r); } // CurveGFp(const CurveGFp& other) = default; @@ -76,6 +78,11 @@ class BOTAN_DLL CurveGFp const BigInt& get_r_inv() const { return r_inv; } /** + * @return a * r mod p + */ + const BigInt& get_a_r() const { return a_r; } + + /** * @return Montgomery parameter p-dash */ word get_p_dash() const { return p_dash; } @@ -108,7 +115,7 @@ class BOTAN_DLL CurveGFp BigInt p, a, b; // Montgomery parameters - BigInt r, r_inv; + BigInt r, r_inv, a_r; word p_dash; Modular_Reducer reducer_p; diff --git a/src/math/numbertheory/point_gfp.cpp b/src/math/numbertheory/point_gfp.cpp index 980bbdc3e..6cc13d648 100644 --- a/src/math/numbertheory/point_gfp.cpp +++ b/src/math/numbertheory/point_gfp.cpp @@ -201,7 +201,7 @@ void PointGFp::mult2() BigInt z4 = monty_mult(coord_z, coord_z); z4 = monty_mult(z4, z4); - BigInt a_z4 = monty_mult(mod_p.multiply(curve.get_r(), curve.get_a()), z4); + BigInt a_z4 = monty_mult(curve.get_a_r(), z4); BigInt M = mod_p.reduce(a_z4 + 3 * monty_mult(coord_x, coord_x)); |