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XY is a misleading variable name, use T instead

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Henry de Valence 2017-02-19 23:51:03 -08:00
parent ec82e7a4f4
commit 0992237233
1 changed files with 5 additions and 5 deletions
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10
src/decaf.rs
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@ -104,7 +104,7 @@ impl DecafPoint {
let mut X = self.0.X;
let mut Y = self.0.Y;
let mut XY = self.0.T;
let mut T = self.0.T;
// If y nonzero and xy nonnegative, continue.
// Otherwise, add Q_6 = (i,0) = constants::EIGHT_TORSION[6]
@ -113,14 +113,14 @@ impl DecafPoint {
// XXX it should be possible to avoid this inversion, but
// let's make sure the code is correct first
let xy = &XY * &self.0.Z.invert();
let xy = &T * &self.0.Z.invert();
let is_neg_mask = 1u8 & !(Y.is_nonzero() & xy.is_nonnegative_decaf());
let iX = &X * &constants::SQRT_M1;
let iY = &Y * &constants::SQRT_M1;
X.conditional_assign(&iY, is_neg_mask);
Y.conditional_assign(&iX, is_neg_mask);
let minus_XY = -&XY;
XY.conditional_assign(&minus_XY, is_neg_mask);
let minus_T = -&T;
T.conditional_assign(&minus_T, is_neg_mask);
// Step 1: Compute r = 1/sqrt((a-d)(Z+Y)(Z-Y))
let Z_plus_Y = &self.0.Z + &Y;
@ -142,7 +142,7 @@ impl DecafPoint {
// Step 4: Compute s = |u(r(aZX - dYT)+Y)/a|
let minus_ZX = -&(&self.0.Z * &X);
let dYT = &constants::d * &(&Y * &XY);
let dYT = &constants::d * &(&Y * &T);
let mut s = &u * &(&(&r * &(&minus_ZX - &dYT)) + &Y);
s.negate();
CompressedDecaf(s.abs_decaf().to_bytes())