diff options
author | lloyd <lloyd@randombit.net> | 2010-03-13 09:37:26 +0000 |
---|---|---|
committer | lloyd <lloyd@randombit.net> | 2010-03-13 09:37:26 +0000 |
commit | 0dd2c107e4ed8ec3c207d1ae9e4ef21702f9d2ba (patch) | |
tree | c2de762f4a2040f9fe4cae69770113ad194816e0 /src | |
parent | 25f27853f11c7c676aab69a41640669193b346e9 (diff) |
Save workspace for addition calls inside operator*=
Diffstat (limited to 'src')
-rw-r--r-- | src/math/numbertheory/point_gfp.cpp | 43 | ||||
-rw-r--r-- | src/math/numbertheory/point_gfp.h | 5 |
2 files changed, 28 insertions, 20 deletions
diff --git a/src/math/numbertheory/point_gfp.cpp b/src/math/numbertheory/point_gfp.cpp index e02b8e87e..2d57b98b2 100644 --- a/src/math/numbertheory/point_gfp.cpp +++ b/src/math/numbertheory/point_gfp.cpp @@ -74,23 +74,20 @@ BigInt PointGFp::monty_mult(const BigInt& a, const BigInt& b, return result; } - -// arithmetic operators -PointGFp& PointGFp::operator+=(const PointGFp& rhs) +void PointGFp::add(const PointGFp& rhs, MemoryRegion<word>& ws) { - if(rhs.is_zero()) - return *this; - if(is_zero()) { - *this = rhs; - return *this; + coord_x = rhs.coord_x; + coord_y = rhs.coord_y; + coord_z = rhs.coord_z; + return; } + else if(rhs.is_zero()) + return; const Modular_Reducer& mod_p = curve.mod_p(); - SecureVector<word> ws(2 * curve.get_p().sig_words() + 1); - BigInt rhs_z2 = monty_mult(rhs.coord_z, rhs.coord_z, ws); BigInt U1 = monty_mult(coord_x, rhs_z2, ws); BigInt S1 = monty_mult(coord_y, monty_mult(rhs.coord_z, rhs_z2, ws), ws); @@ -108,11 +105,11 @@ PointGFp& PointGFp::operator+=(const PointGFp& rhs) if(r.is_zero()) { mult2(ws); - return *this; + return; } *this = PointGFp(curve); // setting myself to zero - return *this; + return; } U2 = monty_mult(H, H, ws); @@ -136,7 +133,13 @@ PointGFp& PointGFp::operator+=(const PointGFp& rhs) coord_x = x; coord_y = y; coord_z = z; + } +// arithmetic operators +PointGFp& PointGFp::operator+=(const PointGFp& rhs) + { + SecureVector<word> ws(2 * curve.get_p().sig_words() + 1); + add(rhs, ws); return *this; } @@ -190,24 +193,24 @@ PointGFp& PointGFp::operator*=(const BigInt& scalar) for(u32bit i = 0; i < scalar_bits - 1; i += 2) { - u32bit twobits = scalar.get_substring(scalar_bits - i - 2, 2); + u32bit nibble = scalar.get_substring(scalar_bits - i - 2, 2); H.mult2(ws); H.mult2(ws); - if(twobits == 3) - H += P3; - else if(twobits == 2) - H += P2; - else if(twobits == 1) - H += P; + if(nibble == 3) + H.add(P3, ws); + else if(nibble == 2) + H.add(P2, ws); + else if(nibble == 1) + H.add(P, ws); } if(scalar_bits % 2) { H.mult2(ws); if(scalar.get_bit(0)) - H += P; + H.add(P, ws); } *this = H; diff --git a/src/math/numbertheory/point_gfp.h b/src/math/numbertheory/point_gfp.h index 0dbd5d319..eaebccf49 100644 --- a/src/math/numbertheory/point_gfp.h +++ b/src/math/numbertheory/point_gfp.h @@ -147,6 +147,11 @@ class BOTAN_DLL PointGFp MemoryRegion<word>& workspace); /** + * Point addition + */ + void add(const PointGFp& other, MemoryRegion<word>& workspace); + + /** * Point doubling */ void mult2(MemoryRegion<word>& workspace); |