diff options
| -rw-r--r-- | src/math/numbertheory/point_gfp.cpp | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/src/math/numbertheory/point_gfp.cpp b/src/math/numbertheory/point_gfp.cpp index 93714e219..25b267822 100644 --- a/src/math/numbertheory/point_gfp.cpp +++ b/src/math/numbertheory/point_gfp.cpp @@ -35,22 +35,21 @@ PointGFp::PointGFp(const CurveGFp& curve, const BigInt& x, const BigInt& y) : BigInt PointGFp::monty_mult(const BigInt& a, const BigInt& b) { - BigInt result = 0; - if(a.is_zero() || b.is_zero()) - return result; + return 0; const BigInt& p = curve.get_p(); const u32bit p_size = p.sig_words(); const word p_dash = curve.get_p_dash(); - result.grow_to(p_size); + BigInt result; + result.grow_to(2*p_size+1); SecureVector<word> t; t.grow_to(2*p_size+1); - if(a > 0 && b > 0 && a < p && b < p && a.size() >= p_size && b.size() >= p_size) + if(a > 0 && b > 0 && a < p && b < p) { bigint_simple_mul(t, a.data(), a.sig_words(), b.data(), b.sig_words()); } @@ -58,18 +57,17 @@ BigInt PointGFp::monty_mult(const BigInt& a, const BigInt& b) { const Modular_Reducer& mod_p = curve.mod_p(); - BigInt a2 = a; - BigInt b2 = b; + BigInt a2 = mod_p.reduce(a); + BigInt b2 = mod_p.reduce(b); + a2.grow_to(p_size); b2.grow_to(p_size); - a2 = mod_p.reduce(a2); - b2 = mod_p.reduce(b2); - bigint_simple_mul(t, a2.data(), a2.sig_words(), b2.data(), b2.sig_words()); } bigint_monty_redc(&t[0], t.size(), p.data(), p_size, p_dash); + copy_mem(&result[0], &t[p_size], p_size); return result; |