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Move fe_frombytes into FieldElement.

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This commit is contained in:
Adam Wick
2019-05-20 21:17:53 -07:00
parent b42902e6ab
commit 8bca480e47
2 changed files with 62 additions and 70 deletions
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51
src/ed25519/point.rs
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@@ -39,7 +39,6 @@ impl Point {
/// statically timed, so don't use it if that's important to you.
pub fn from_bytes(s: &[u8]) -> Option<Point>
{
let mut h = Point::new();
let mut u = FieldElement::new();
let mut v = FieldElement::new();
let mut v3 = FieldElement::new();
@@ -47,32 +46,33 @@ impl Point {
let mut check = FieldElement::new();
let mut temp;
fe_frombytes(&mut h.y, s);
h.z.overwrite_with(&FieldElement::one());
fe_square(&mut u, &h.y);
let hy = FieldElement::from_bytes(s);
let hz = FieldElement::one();
fe_square(&mut u, &hy);
fe_mul(&mut v, &u, &D);
temp = u.clone();
fe_sub(&mut u, &temp, &h.z); /* u = y^2-1 */
fe_sub(&mut u, &temp, &hz); /* u = y^2-1 */
temp = v.clone();
fe_add(&mut v, &temp, &h.z); /* v = dy^2+1 */
fe_add(&mut v, &temp, &hz); /* v = dy^2+1 */
fe_square(&mut v3, &v);
temp = v3.clone();
fe_mul(&mut v3, &temp, &v); /* v3 = v^3 */
fe_square(&mut h.x, &v3);
temp = h.x.clone();
fe_mul(&mut h.x, &temp, &v);
temp = h.x.clone();
fe_mul(&mut h.x, &temp, &u); /* x = uv^7 */
let mut hx = FieldElement::zero();
fe_square(&mut hx, &v3);
temp = hx.clone();
fe_mul(&mut hx, &temp, &v);
temp = hx.clone();
fe_mul(&mut hx, &temp, &u); /* x = uv^7 */
temp = h.x.clone();
fe_pow22523(&mut h.x, &temp); /* x = (uv^7)^((q-5)/8) */
temp = h.x.clone();
fe_mul(&mut h.x, &temp, &v3);
temp = h.x.clone();
fe_mul(&mut h.x, &temp, &u); /* x = uv^3(uv^7)^((q-5)/8) */
temp = hx.clone();
fe_pow22523(&mut hx, &temp); /* x = (uv^7)^((q-5)/8) */
temp = hx.clone();
fe_mul(&mut hx, &temp, &v3);
temp = hx.clone();
fe_mul(&mut hx, &temp, &u); /* x = uv^3(uv^7)^((q-5)/8) */
fe_square(&mut vxx, &h.x);
fe_square(&mut vxx, &hx);
temp = vxx.clone();
fe_mul(&mut vxx, &temp, &v);
fe_sub(&mut check, &vxx, &u); /* vx^2-u */
@@ -81,17 +81,18 @@ impl Point {
if fe_isnonzero(&check) {
return None;
}
temp = h.x.clone();
fe_mul(&mut h.x, &temp, &SQRTM1);
temp = hx.clone();
fe_mul(&mut hx, &temp, &SQRTM1);
}
if fe_isnegative(&h.x) != ((s[31] >> 7) == 1) {
temp = h.x.clone();
fe_neg(&mut h.x, &temp);
if fe_isnegative(&hx) != ((s[31] >> 7) == 1) {
temp = hx.clone();
fe_neg(&mut hx, &temp);
}
fe_mul(&mut h.t, &h.x, &h.y);
return Some(h);
let mut ht = FieldElement::zero();
fe_mul(&mut ht, &hx, &hy);
return Some(Point{ x: hx, y: hy, z: hz, t: ht });
}
pub fn encode_to(&self, target: &mut [u8])