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[FIXED] Fairly ridiculous implementation of ECDSA verification

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This commit is contained in:
Adam Wick
2019-02-11 12:10:59 -08:00
parent 94defc4e77
commit 9ce976bb6e
2 changed files with 49 additions and 39 deletions
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46
src/ecdsa/point.rs
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@@ -2,16 +2,22 @@ use cryptonum::signed::*;
use cryptonum::unsigned::*;
use ecdsa::curve::*;
pub trait ECCPoint {
pub trait ECCPoint : Sized {
type Curve: EllipticCurve;
type Scale;
fn default() -> Self;
fn double_scalar_mult(x1: &Self::Scale, p1: &Self, x2: &Self::Scale, p2: &Self) -> Self;
fn negate(&self) -> Self;
fn double(&self) -> Self;
fn add(&self, other: &Self) -> Self;
fn scale(&self, amt: &Self::Scale) -> Self;
fn double_scalar_mult(x1: &Self::Scale, p1: &Self, x2: &Self::Scale, p2: &Self) -> Self
{
// FIXME: Replace this with something not stupid.
let big1 = p1.scale(x1);
let big2 = p2.scale(x2);
big1.add(&big2)
}
}
pub struct Point<T: EllipticCurve>
@@ -47,42 +53,6 @@ macro_rules! point_impl
}
}
fn double_scalar_mult(x1: &$base, p1: &Self, x2: &$base, p2: &Self) -> Self
{
if x1.is_negative() {
return Point::<$curve>::double_scalar_mult(&x1.abs(), &p1.negate(), x2, p2);
}
if x2.is_negative() {
return Point::<$curve>::double_scalar_mult(x1, p2, &x2.abs(), &p2.negate());
}
let p0 = p1.add(p2);
let mut i = $curve::size() - 1;
// Find the point where we should start our loop
assert!(!x1.is_zero() || !x2.is_zero());
while x1.testbit(i) || x2.testbit(i) { i -= 1; }
// our base value is the addition of the input points
let mut acc = p1.add(&p2);
loop {
let q = acc.double();
match (x1.testbit(i), x2.testbit(i)) {
(true, true) => acc = p0.add(&q),
(true, false) => acc = p1.add(&q),
(false, true) => acc = p2.add(&q),
(false, false) => acc = q
}
if i == 0 {
return acc;
} else {
i -= 1;
}
}
}
fn negate(&self) -> Point<$curve>
{
let mut newy = $base::new(false, $curve::p());