fixed poly

This commit is contained in:
Christoph J. Scherr 2023-06-08 15:01:31 +02:00
parent d494db5216
commit a4ac68528c
Signed by: PlexSheep
GPG Key ID: 25B4ACF7D88186CC
1 changed files with 92 additions and 49 deletions

View File

@ -1,8 +1,10 @@
#![allow(dead_code)] #![allow(dead_code)]
/// eliptic curve cryptography use std::{ops::{Mul, Neg}, fmt::Debug};
/// eliptic curve cryptograp.s
/// ///
/// This module implements structs and functionalities used for eliptic curve cryptography (ECC). /// This module implements structs and functionalities used for eliptic curve cryptograp.s (ECC).
/// Do not expect it to actually be secure, I made this for cryptography lectures. /// Do not expect it to actually be secure, I made this for cryptograp.s lectures.
/// ///
/// Author: Christoph J. Scherr <software@cscherr.de> /// Author: Christoph J. Scherr <software@cscherr.de>
/// License: MIT /// License: MIT
@ -10,19 +12,11 @@
use super::gallois::GalloisField; use super::gallois::GalloisField;
use num::Integer;
use pyo3::prelude::*; use pyo3::prelude::*;
/// This is a very special math point, it does not really exist but is useful.
pub const INFINITY_POINT: ElipticCurvePoint = ElipticCurvePoint {
x: 0,
y: 0,
is_infinity_point: true,
verbose: false
};
#[derive(Debug, Clone)] #[derive(Debug, Clone)]
#[allow(non_snake_case)] #[allow(non_snake_case)]
#[pyclass]
/// represent a specific eliptic curve /// represent a specific eliptic curve
/// ///
/// real curves not supported, only in Gallois Fields /// real curves not supported, only in Gallois Fields
@ -32,36 +26,56 @@ pub struct ElipticCurve {
b: i128, b: i128,
points: Vec<ElipticCurvePoint>, points: Vec<ElipticCurvePoint>,
verbose: bool, verbose: bool,
INFINITY_POINT: ElipticCurvePoint, INFINITY_POINT: Option<ElipticCurvePoint>
} }
impl ElipticCurve { impl ElipticCurve {
pub fn new(f: GalloisField, a: i128, b: i128, verbose: bool) -> Self { pub fn new(f: GalloisField, a: i128, b: i128, verbose: bool) -> Self {
let e = ElipticCurve { let mut e = ElipticCurve {
f, f,
a, a,
b, b,
points: Vec::new(), points: Vec::new(),
verbose, verbose,
INFINITY_POINT INFINITY_POINT: None
}; };
let infty = ElipticCurvePoint::new(0, 0, e.f);
e.INFINITY_POINT = Some(infty);
return e; return e;
} }
/// calculate a point for coordinates /// calculate a value for coordinates
pub fn poly(&self, x: i128, y: i128) -> i128 { pub fn poly<T>(&self, r: T, s: T) -> i128
return y.pow(2) - x.pow(3) - (self.a * x) - self.b; where
T: Integer,
T: Mul,
T: Debug,
T: num::cast::AsPrimitive<i128>,
T: Neg
{
dbg!(&r);
dbg!(&s);
let r: i128 = num::cast::AsPrimitive::as_(r);
let s: i128 = num::cast::AsPrimitive::as_(s);
let res = s.pow(2) - r.pow(3) - (self.a * r) - self.b;
let res1 = self.f.reduce(res);
if self.verbose {
println!("F({}, {}) = {}² - {}³ - {} * {} - {} = {res} = {res1}",
r, s, s, r, self.a, r, self.b
);
}
return res1 as i128;
} }
pub fn check_point(self, p: ElipticCurvePoint) -> bool { pub fn check_point(self, p: ElipticCurvePoint) -> bool {
let mut valid = true; let mut valid = true;
let r = self.f.reduce(self.poly(p.x, p.y)); let res = self.f.reduce(self.poly(p.r, p.s));
if self.verbose { if self.verbose {
println!("F({}, {}) = {}² - {}³ - {} * {} - {} = {r}", println!("F({}, {}) = {}² - {}³ - {} * {} - {} = {res}",
p.x, p.y, p.y, p.x, self.a, p.x, self.b p.r, p.s, p.s, p.r, self.a, p.r, self.b
) )
} }
valid &= r == 0; valid &= res == 0;
return valid; return valid;
} }
} }
@ -72,15 +86,15 @@ fn test_check_point() {
let ec = ElipticCurve::new(f, 1, 679, true); let ec = ElipticCurve::new(f, 1, 679, true);
// real points // real points
let p = vec![ let p = vec![
ElipticCurvePoint::new(298, 531), ElipticCurvePoint::new(298, 531, f),
ElipticCurvePoint::new(600, 127), ElipticCurvePoint::new(600, 127, f),
ElipticCurvePoint::new(846, 176), ElipticCurvePoint::new(846, 176, f),
]; ];
// random values, not part of the ec. // random values, not part of the e, fc.
let np = vec![ let np = vec![
ElipticCurvePoint::new(198, 331), ElipticCurvePoint::new(198, 331, f),
ElipticCurvePoint::new(100, 927), ElipticCurvePoint::new(100, 927, f),
ElipticCurvePoint::new(446, 876), ElipticCurvePoint::new(446, 876, f),
]; ];
for i in p { for i in p {
dbg!(&i); dbg!(&i);
@ -94,43 +108,72 @@ fn test_check_point() {
#[derive(Debug, Clone, Copy)] #[derive(Debug, Clone, Copy)]
#[pyclass]
/// represent a specific eliptic curves point /// represent a specific eliptic curves point
pub struct ElipticCurvePoint { pub struct ElipticCurvePoint {
x: i128, r: i128,
y: i128, s: i128,
is_infinity_point: bool, is_infinity_point: bool,
verbose: bool field: GalloisField
} }
impl ElipticCurvePoint { impl ElipticCurvePoint {
pub fn new(x: i128, y: i128) -> Self { pub fn new(r: i128, s: i128, field: GalloisField) -> ElipticCurvePoint {
ElipticCurvePoint { ElipticCurvePoint {
x, r,
y, s,
is_infinity_point: false, is_infinity_point: false,
verbose: false field
} }
} }
pub fn get_infinity_point() -> Self {
return INFINITY_POINT;
}
/// add two points /// add two points
pub fn add(a: Self, b: Self) -> Self { pub fn add(self, point: Self) -> Result<Self, String> {
// TODO if self.field.cha != point.field.cha {
panic!("TODO"); return Err(String::from("Points are not on the same field"));
}
if self.field.prime_base {
// case 1 both infty
if self.is_infinity_point && point.is_infinity_point {
return Ok(point);
}
// case 2 one is infty
else if self.is_infinity_point && !point.is_infinity_point {
return Ok(point);
}
else if !self.is_infinity_point && point.is_infinity_point {
return Ok(self);
}
// case 3 r_1 != r_2
else if self.r != point.r {
panic!("TODO");
}
// case 4 r_1 = r_2; s_1 = -s_2
else if self.r == point.r && self.s == point.neg().s {
return Ok(Self::new(0, 0, self.field));
}
// how do we get here?
// this should never occur
else {
panic!("we dont know what to do in this case?")
}
}
else {
return Err(String::from("Only prime fields are supported currently"));
}
} }
/// get negative of a point /// get negative of a point
pub fn neg(p: Self) -> Self { pub fn neg(self) -> Self {
// TODO return ElipticCurvePoint::new(
panic!("TODO"); self.r,
self.field.reduce(-(self.s as i128)) as i128,
self.field
);
} }
/// multiply a point by an integer /// multip.s a point by an integer
pub fn mul(n: u128, a: Self) -> Self { pub fn mul(self, n: u128) -> Self {
// TODO // TODO
panic!("TODO"); panic!("TODO");
} }