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multiexp: fix wrong Bos-Coster result for 1 non trivial input

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Reported by QuarksLab.
This commit is contained in:
moneromooo-monero 2018-07-24 20:26:43 +01:00
parent a1359ad43c
commit 0825e97436
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1 changed files with 7 additions and 3 deletions
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10
src/ringct/multiexp.cc
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@ -222,17 +222,21 @@ rct::key bos_coster_heap_conv_robust(std::vector<MultiexpData> data)
points = heap.size(); points = heap.size();
if (points == 0) if (points == 0)
return rct::identity(); return rct::identity();
auto Comp = [&](size_t e0, size_t e1) { return data[e0].scalar < data[e1].scalar; };
std::make_heap(heap.begin(), heap.end(), Comp);
if (points < 2) if (points < 2)
{ {
std::pop_heap(heap.begin(), heap.end(), Comp);
size_t index1 = heap.back();
ge_p2 p2; ge_p2 p2;
ge_scalarmult(&p2, data[0].scalar.bytes, &data[0].point); ge_scalarmult(&p2, data[index1].scalar.bytes, &data[index1].point);
rct::key res; rct::key res;
ge_tobytes(res.bytes, &p2); ge_tobytes(res.bytes, &p2);
return res; return res;
} }
auto Comp = [&](size_t e0, size_t e1) { return data[e0].scalar < data[e1].scalar; };
std::make_heap(heap.begin(), heap.end(), Comp);
MULTIEXP_PERF(PERF_TIMER_STOP(setup)); MULTIEXP_PERF(PERF_TIMER_STOP(setup));
MULTIEXP_PERF(PERF_TIMER_START_UNIT(loop, 1000000)); MULTIEXP_PERF(PERF_TIMER_START_UNIT(loop, 1000000));