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Use From methods, rather than function converters.

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This commit is contained in:
Adam Wick
2019-05-26 15:21:59 -07:00
parent 2f395721bc
commit 83cdd8ef4c
1 changed files with 80 additions and 91 deletions
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171
src/ed25519/point.rs
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@@ -14,16 +14,6 @@ pub struct Point {
}
impl Point {
pub fn new() -> Point
{
Point {
x: FieldElement::new(),
y: FieldElement::new(),
z: FieldElement::new(),
t: FieldElement::new()
}
}
fn zero() -> Point
{
Point {
@@ -134,15 +124,6 @@ pub struct Point2 {
}
impl Point2 {
pub fn new() -> Point2
{
Point2 {
x: FieldElement::new(),
y: FieldElement::new(),
z: FieldElement::new()
}
}
pub fn zero() -> Point2
{
Point2 {
@@ -168,11 +149,14 @@ impl Point2 {
}
}
fn ge_p3_to_p2(r: &mut Point2, p: &Point)
{
r.x.overwrite_with(&p.x);
r.y.overwrite_with(&p.y);
r.z.overwrite_with(&p.z);
impl<'a> From<&'a Point> for Point2 {
fn from(p: &Point) -> Point2 {
Point2 {
x: p.x.clone(),
y: p.y.clone(),
z: p.z.clone(),
}
}
}
#[derive(Debug,PartialEq)]
@@ -243,29 +227,42 @@ const D2: FieldElement = FieldElement {
15978800, -12551817, -6495438, 29715968, 9444199]
};
fn x25519_ge_p3_to_cached(r: &mut Cached, p: &Point)
impl<'a> From<&'a Point> for Cached
{
r.yplusx = &p.y + &p.x;
r.yminusx = &p.y - &p.x;
r.z.overwrite_with(&p.z);
r.t2d = &p.t * &D2;
fn from(p: &Point) -> Cached
{
Cached {
yplusx: &p.y + &p.x,
yminusx: &p.y - &p.x,
z: p.z.clone(),
t2d: &p.t * &D2,
}
}
}
/* r = p */
fn x25519_ge_p1p1_to_p2(r: &mut Point2, p: &PointP1P1)
impl<'a> From<&'a PointP1P1> for Point2
{
r.x = &p.x * &p.t;
r.y = &p.y * &p.z;
r.z = &p.z * &p.t;
fn from(p: &PointP1P1) -> Point2
{
Point2 {
x: &p.x * &p.t,
y: &p.y * &p.z,
z: &p.z * &p.t,
}
}
}
/* r = p */
fn x25519_ge_p1p1_to_p3(r: &mut Point, p: &PointP1P1)
impl<'a> From<&'a PointP1P1> for Point
{
r.x = &p.x * &p.t;
r.y = &p.y * &p.z;
r.z = &p.z * &p.t;
r.t = &p.x * &p.y;
fn from(p: &PointP1P1) -> Point
{
Point {
x: &p.x * &p.t,
y: &p.y * &p.z,
z: &p.z * &p.t,
t: &p.x * &p.y,
}
}
}
#[cfg(test)]
@@ -289,24 +286,20 @@ fn conversion() {
assert!(!nega && !negc && !negt && !nego && !negd && !negb);
let mut myc = Cached::new();
x25519_ge_p3_to_cached(&mut myc, &a);
let myc = Cached::from(&a);
assert_eq!(myc, c);
let mut myt = Point2::new();
ge_p3_to_p2(&mut myt, &a);
let myt = Point2::from(&a);
assert_eq!(myt, t);
let mut myo = PointP1P1::new();
ge_p3_dbl(&mut myo, &a);
assert_eq!(myo, o);
let mut myd = Point2::new();
x25519_ge_p1p1_to_p2(&mut myd, &o);
let myd = Point2::from(&o);
assert_eq!(myd, d);
let mut myb = Point::new();
x25519_ge_p1p1_to_p3(&mut myb, &o);
let myb = Point::from(&o);
assert_eq!(myb, b);
});
}
@@ -328,8 +321,7 @@ fn ge_p2_dbl(r: &mut PointP1P1, p: &Point2)
/* r = 2 * p */
fn ge_p3_dbl(r: &mut PointP1P1, p: &Point)
{
let mut q = Point2::new();
ge_p3_to_p2(&mut q, p);
let q = Point2::from(p);
ge_p2_dbl(r, &q);
}
@@ -515,46 +507,45 @@ impl Point {
{
let mut e: [i8; 64] = [0; 64];
for i in 0..32 {
e[2 * i + 0] = ((a[i] >> 0) & 15) as i8;
e[2 * i + 1] = ((a[i] >> 4) & 15) as i8;
e[2 * i + 0] = ((a[i] >> 0) & 15) as i8;
e[2 * i + 1] = ((a[i] >> 4) & 15) as i8;
}
/* each e[i] is between 0 and 15 */
/* e[63] is between 0 and 7 */
let mut carry = 0;
for i in 0..63 {
e[i] += carry;
carry = e[i] + 8;
carry >>= 4;
e[i] -= carry << 4;
e[i] += carry;
carry = e[i] + 8;
carry >>= 4;
e[i] -= carry << 4;
}
e[63] += carry;
/* each e[i] is between -8 and 8 */
let mut r = PointP1P1::new();
let mut s = Point2::new();
let mut t;
let mut h = Point::zero();
for i in &[1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,53,55,57,59,61,63] {
t = table_select(*i / 2, e[*i as usize]);
ge_madd(&mut r, &h, &t);
x25519_ge_p1p1_to_p3(&mut h, &r);
t = table_select(*i / 2, e[*i as usize]);
ge_madd(&mut r, &h, &t);
h = Point::from(&r);
}
ge_p3_dbl(&mut r, &h);
x25519_ge_p1p1_to_p2(&mut s, &r);
let mut s = Point2::from(&r);
ge_p2_dbl(&mut r, &s);
x25519_ge_p1p1_to_p2(&mut s, &r);
s = Point2::from(&r);
ge_p2_dbl(&mut r, &s);
x25519_ge_p1p1_to_p2(&mut s, &r);
s = Point2::from(&r);
ge_p2_dbl(&mut r, &s);
x25519_ge_p1p1_to_p3(&mut h, &r);
h = Point::from(&r);
for i in &[0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62] {
t = table_select(*i / 2, e[*i as usize]);
ge_madd(&mut r, &h, &t);
x25519_ge_p1p1_to_p3(&mut h, &r);
t = table_select(*i / 2, e[*i as usize]);
ge_madd(&mut r, &h, &t);
h = Point::from(&r);
}
h
@@ -639,37 +630,35 @@ pub fn ge_double_scalarmult_vartime(a: &[u8], A: &Point, b: &[u8]) -> Point2
let mut Ai: [Cached; 8] = [Cached::new(), Cached::new(), Cached::new(), Cached::new(),
Cached::new(), Cached::new(), Cached::new(), Cached::new()];
let mut t = PointP1P1::new();
let mut u = Point::new();
#[allow(non_snake_case)]
let mut A2 = Point::new();
slide(&mut aslide, &a);
slide(&mut bslide, &b);
x25519_ge_p3_to_cached(&mut Ai[0], &A);
Ai[0] = Cached::from(A);
ge_p3_dbl(&mut t, &A);
x25519_ge_p1p1_to_p3(&mut A2, &t);
let A2 = Point::from(&t);
x25519_ge_add(&mut t, &A2, &Ai[0]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[1], &u);
let mut u = Point::from(&t);
Ai[1] = Cached::from(&u);
x25519_ge_add(&mut t, &A2, &Ai[1]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[2], &u);
u = Point::from(&t);
Ai[2] = Cached::from(&u);
x25519_ge_add(&mut t, &A2, &Ai[2]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[3], &u);
u = Point::from(&t);
Ai[3] = Cached::from(&u);
x25519_ge_add(&mut t, &A2, &Ai[3]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[4], &u);
u = Point::from(&t);
Ai[4] = Cached::from(&u);
x25519_ge_add(&mut t, &A2, &Ai[4]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[5], &u);
u = Point::from(&t);
Ai[5] = Cached::from(&u);
x25519_ge_add(&mut t, &A2, &Ai[5]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[6], &u);
u = Point::from(&t);
Ai[6] = Cached::from(&u);
x25519_ge_add(&mut t, &A2, &Ai[6]);
x25519_ge_p1p1_to_p3(&mut u, &t);
x25519_ge_p3_to_cached(&mut Ai[7], &u);
u = Point::from(&t);
Ai[7] = Cached::from(&u);
let mut r = Point2::zero();
@@ -688,26 +677,26 @@ pub fn ge_double_scalarmult_vartime(a: &[u8], A: &Point, b: &[u8]) -> Point2
ge_p2_dbl(&mut t, &r);
if aslide[i as usize] > 0 {
x25519_ge_p1p1_to_p3(&mut u, &t);
u = Point::from(&t);
let idx = (aslide[i as usize] / 2) as usize;
x25519_ge_add(&mut t, &u, &Ai[idx]);
} else if aslide[i as usize] < 0 {
x25519_ge_p1p1_to_p3(&mut u, &t);
u = Point::from(&t);
let idx = ((-aslide[i as usize]) / 2) as usize;
x25519_ge_sub(&mut t, &u, &Ai[idx]);
}
if bslide[i as usize] > 0 {
x25519_ge_p1p1_to_p3(&mut u, &t);
u = Point::from(&t);
let idx = (bslide[i as usize] / 2) as usize;
ge_madd(&mut t, &u, &BI[idx]);
} else if bslide[i as usize] < 0 {
x25519_ge_p1p1_to_p3(&mut u, &t);
u = Point::from(&t);
let idx = ((-bslide[i as usize]) / 2) as usize;
ge_msub(&mut t, &u, &BI[idx]);
}
x25519_ge_p1p1_to_p2(&mut r, &t);
r = Point2::from(&t);
i -= 1;
}