diff options
| -rw-r--r-- | src/math/numbertheory/curve_gfp.h | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/src/math/numbertheory/curve_gfp.h b/src/math/numbertheory/curve_gfp.h index de6bed099..3c9eb90ca 100644 --- a/src/math/numbertheory/curve_gfp.h +++ b/src/math/numbertheory/curve_gfp.h @@ -34,29 +34,52 @@ class BOTAN_DLL CurveGFp * @param b second coefficient */ CurveGFp(const BigInt& p, const BigInt& a, const BigInt& b) : - p(p), a(a), b(b), reducer_p(p) {} + p(p), a(a), b(b), reducer_p(p) + { + r = 1; + r <<= p.sig_words() * BOTAN_MP_WORD_BITS; + + r_inv = inverse_mod(r, p); + + p_dash = ((r * r_inv) - 1) / p; + } // CurveGFp(const CurveGFp& other) = default; // CurveGFp& operator=(const CurveGFp& other) = default; /** * Get coefficient a - * @result coefficient a + * @return coefficient a */ const BigInt& get_a() const { return a; } /** * Get coefficient b - * @result coefficient b + * @return coefficient b */ const BigInt& get_b() const { return b; } /** * Get prime modulus of the field of the curve - * @result prime modulus of the field of the curve + * @return prime modulus of the field of the curve */ const BigInt& get_p() const { return p; } + /** + * @return Montgomery parameter r + */ + const BigInt& get_r() const { return r; } + + /** + * @return Montgomery parameter r^-1 + */ + const BigInt& get_r_inv() const { return r_inv; } + + /** + * @return Montgomery parameter p-dash + */ + const BigInt& get_p_dash() const { return p_dash; } + const Modular_Reducer& mod_p() const { return reducer_p; } /** @@ -68,6 +91,11 @@ class BOTAN_DLL CurveGFp std::swap(a, other.a); std::swap(b, other.b); std::swap(p, other.p); + std::swap(reducer_p, other.reducer_p); + + std::swap(r, other.r); + std::swap(r_inv, other.r_inv); + std::swap(p_dash, other.p_dash); } bool operator==(const CurveGFp& other) const @@ -76,7 +104,12 @@ class BOTAN_DLL CurveGFp } private: + // Curve parameters BigInt p, a, b; + + // Montgomery parameters + BigInt r, r_inv, p_dash; + Modular_Reducer reducer_p; }; |