Compression/Decompression of G2 Points for BLS12_381 #909
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Additional details and impacted files@@ Coverage Diff @@
## main #909 +/- ##
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+ Coverage 72.66% 72.81% +0.15%
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Files 150 150
Lines 34057 34151 +94
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+ Hits 24746 24866 +120
+ Misses 9311 9285 -26 ☔ View full report in Codecov by Sentry. |
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| // Set the 3rd bit based on y value. | ||
| let y_neg = -y; | ||
| if y.value()[0].representative() > y_neg.value()[0].representative() |
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This condition should be y.value()[0].representative() > y_neg.value()[0].representative() || (y.value()[0].representative() == y_neg.value()[0].representative() && y.value()[1].representative() > y_neg.value()[1].representative()).
Perhaps a more efficient strategy is
y_is_greater_or_equal = y.value()[0].representative() >= y_neg.value()[0].representative().
if y_is_greater_or_equal || (y_is_greater_or_equal && y.value()[1].representative() > y_neg.value()[1].representative()
…mbdaworks into fix_bls12_381_compression
| x_bytes[0] |= 1 << 7; | ||
| x_bytes[0] |= 1 << 6; |
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| x_bytes[0] |= 1 << 7; | |
| x_bytes[0] |= 1 << 6; | |
| x_bytes[0] |= 0b11 << 6; |
| @@ -106,7 +102,48 @@ impl Compress for BLS12381Curve { | |||
| .ok_or(ByteConversionError::PointNotInSubgroup) | |||
| } | |||
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| #[allow(unused)] | |||
| #[cfg(feature = "alloc")] | |||
| fn compress_g2_point(point: &Self::G2Point) -> alloc::vec::Vec<u8> { | |||
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Do we really need a Vec here or is it constant size?
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Traits get in the way, but we can try to solve this if we expose more things
Compression/Decompression of G2 Points for BLS12_381
This PR fixes a bug in the function responsible for decompressing points on the BLS12_381 curve, where the 3rd bit was not being properly accounted for.
It also adds functionality for compressing points on this curve.
Type of change
Checklist