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fix inconsistency in variable naming

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Henry de Valence 2018-01-10 06:04:03 -08:00
parent 841c026c13
commit a0c93cb730
1 changed files with 9 additions and 12 deletions
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21
src/montgomery.rs
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@ -336,29 +336,26 @@ fn differential_add_and_double(P: &mut MontgomeryPoint, Q: &mut MontgomeryPoint,
let t13 = &APLUS2_OVER_FOUR * &t6; // (A + 2) U_P U_Q let t13 = &APLUS2_OVER_FOUR * &t6; // (A + 2) U_P U_Q
let t14 = &t4 * &t5; // ((U_P + W_P)(U_P - W_P))^2 = (U_P^2 - W_P^2)^2 // P'_U let t14 = &t4 * &t5; // ((U_P + W_P)(U_P - W_P))^2 = (U_P^2 - W_P^2)^2
let t15 = &t13 + &t5; // (U_P - W_P)^2 + (A + 2) U_P W_P let t15 = &t13 + &t5; // (U_P - W_P)^2 + (A + 2) U_P W_P
let t16 = &t6 * &t15; // 4 (U_P W_P) ((U_P - W_P)^2 + (A + 2) U_P W_P) // P'_W let t16 = &t6 * &t15; // 4 (U_P W_P) ((U_P - W_P)^2 + (A + 2) U_P W_P)
let t17 = &difference.U * &t12; // D_U * 4 (W_P U_Q - U_P W_Q)^2 // Q'_W let t17 = &difference.U * &t12; // U_D * 4 (W_P U_Q - U_P W_Q)^2
let t18 = &difference.W * &t11; // D_W * 4 (U_P U_Q - W_P W_Q)^2 // Q'_U let t18 = &difference.W * &t11; // W_D * 4 (U_P U_Q - W_P W_Q)^2
P.U = t14; // P'_U = (U_P + W_P)^2 (U_P - W_P)^2 P.U = t14; // U_{P'} = (U_P + W_P)^2 (U_P - W_P)^2
P.W = t16; // P'_W = (4 U_P W_P) ((U_P - W_P)^2 + ((A + 2)/4) 4 U_P W_P) P.W = t16; // W_{P'} = (4 U_P W_P) ((U_P - W_P)^2 + ((A + 2)/4) 4 U_P W_P)
Q.U = t18; // Q'_U = D_W * 4 (U_P U_Q - W_P W_Q)^2 Q.U = t18; // U_{Q'} = D_W * 4 (U_P U_Q - W_P W_Q)^2
Q.W = t17; Q.W = t17; // W_{Q'} = U_D * 4 (W_P U_Q - U_P W_Q)^2
} }
/// Multiply this `MontgomeryPoint` by a `Scalar`. /// Multiply this `MontgomeryPoint` by a `Scalar`.
///
/// The reader is refered to §5.3 of ["Montgomery Curves and Their Arithmetic"
/// by Craig Costello and Benjamin Smith](https://eprint.iacr.org/2017/212.pdf)
/// for an overview of side-channel-free Montgomery laddering algorithms.
impl<'a, 'b> Mul<&'b Scalar> for &'a MontgomeryPoint { impl<'a, 'b> Mul<&'b Scalar> for &'a MontgomeryPoint {
type Output = MontgomeryPoint; type Output = MontgomeryPoint;
fn mul(self, scalar: &'b Scalar) -> MontgomeryPoint { fn mul(self, scalar: &'b Scalar) -> MontgomeryPoint {
// Algorithm 8 of Costello-Smith 2017
let mut x0: MontgomeryPoint = MontgomeryPoint::identity(); let mut x0: MontgomeryPoint = MontgomeryPoint::identity();
let mut x1: MontgomeryPoint = *self; let mut x1: MontgomeryPoint = *self;