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errata and basepoint_odd_lookup_table test for better understanding

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(cherry picked from commit 8da05f7e90)
Signed-off-by: Isis Lovecruft <isis@patternsinthevoid.net>
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root 2019-09-04 12:38:02 +08:00 committed by Isis Lovecruft
parent 87a5ed78b7
commit 4b268a9d7e
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2 changed files with 22 additions and 2 deletions
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2
docs/parallel-formulas.md
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@ -327,7 +327,7 @@ There are several directions for future improvement:
[sandy2x]: https://eprint.iacr.org/2015/943.pdf
[avx2trac]: https://trac.torproject.org/projects/tor/ticket/8897#comment:28
[hwcd08]: https://www.iacr.org/archive/asiacrypt2008/53500329/53500329.pdf
[curve_models]: https://doc-internal.dalek.rs/curve25519_dalek/curve_models/index.html
[curve_models]: https://doc-internal.dalek.rs/curve25519_dalek/backend/serial/curve_models/index.html
[bbjlp08]: https://eprint.iacr.org/2008/013
[cmo98]: https://link.springer.com/content/pdf/10.1007%2F3-540-49649-1_6.pdf
[intel]: https://software.intel.com/sites/default/files/managed/9e/bc/64-ia-32-architectures-optimization-manual.pdf

22
src/backend/vector/avx2/edwards.rs
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@ -47,6 +47,7 @@ use traits::Identity;
use super::constants;
use super::field::{FieldElement2625x4, Lanes, Shuffle};
use backend::vector::avx2::constants::{BASEPOINT_ODD_LOOKUP_TABLE};
/// A point on Curve25519, using parallel Edwards formulas for curve
/// operations.
@ -188,7 +189,7 @@ impl From<ExtendedPoint> for CachedPoint {
let mut x = P.0;
x = x.blend(x.diff_sum(), Lanes::AB);
// x = (X1 - Y1, X2 + Y2, Z2, T2) = (S2 S3 Z2 T2)
// x = (Y2 - X2, Y2 + X2, Z2, T2) = (S2 S3 Z2 T2)
x = x * (121666, 121666, 2 * 121666, 2 * 121665);
// x = (121666*S2 121666*S3 2*121666*Z2 2*121665*T2)
@ -521,4 +522,23 @@ mod test {
let P = &constants::ED25519_BASEPOINT_TABLE * &Scalar::from(8475983829u64);
doubling_test_helper(P);
}
#[test]
fn basepoint_odd_lookup_table_verify() {
use constants;
let basepoint_odd_table = NafLookupTable8::<CachedPoint>::from(&constants::ED25519_BASEPOINT_POINT);
println!("basepoint_odd_lookup_table = {:?}", basepoint_odd_table);
let table_B = &BASEPOINT_ODD_LOOKUP_TABLE;
for (b_vec, base_vec) in table_B.0.iter().zip(basepoint_odd_table.0.iter()) {
let b_splits = b_vec.0.split();
let base_splits = base_vec.0.split();
assert_eq!(base_splits[0], b_splits[0]);
assert_eq!(base_splits[1], b_splits[1]);
assert_eq!(base_splits[2], b_splits[2]);
assert_eq!(base_splits[3], b_splits[3]);
}
}
}