5 changed files with 386 additions and 629 deletions
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+0 -11.github/workflows/clippy.yml
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+14 -9Cargo.toml
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+4 -2README.md
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+368 -346src/lib.rs
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+0 -261src/utils.rs
@ -1,11 +0,0 @@ |
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name: Clippy check |
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on: [push, pull_request] |
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jobs: |
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clippy_check: |
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runs-on: ubuntu-latest |
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steps: |
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- uses: actions/checkout@v1 |
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- run: rustup component add clippy |
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- uses: actions-rs/clippy-check@v1 |
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with: |
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token: ${{ secrets.GITHUB_TOKEN }} |
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@ -1,261 +0,0 @@ |
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// BabyJubJub elliptic curve implementation in Rust.
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// For LICENSE check https://github.com/arnaucube/babyjubjub-rs
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use num_bigint::{BigInt, ToBigInt};
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use num_traits::{One, Zero};
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pub fn modulus(a: &BigInt, m: &BigInt) -> BigInt {
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((a % m) + m) % m
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}
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pub fn modinv(a: &BigInt, q: &BigInt) -> Result<BigInt, String> {
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let big_zero: BigInt = Zero::zero();
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if a == &big_zero {
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return Err("no mod inv of Zero".to_string());
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}
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let mut mn = (q.clone(), a.clone());
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let mut xy: (BigInt, BigInt) = (Zero::zero(), One::one());
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while mn.1 != big_zero {
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xy = (xy.1.clone(), xy.0 - (mn.0.clone() / mn.1.clone()) * xy.1);
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mn = (mn.1.clone(), modulus(&mn.0, &mn.1));
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}
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while xy.0 < Zero::zero() {
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xy.0 = modulus(&xy.0, q);
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}
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Ok(xy.0)
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}
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/*
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pub fn modinv_v2(a0: &BigInt, m0: &BigInt) -> BigInt {
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if m0 == &One::one() {
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return One::one();
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}
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let (mut a, mut m, mut x0, mut inv): (BigInt, BigInt, BigInt, BigInt) =
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(a0.clone(), m0.clone(), Zero::zero(), One::one());
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while a > One::one() {
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inv = inv - (&a / m.clone()) * x0.clone();
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a = a % m.clone();
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std::mem::swap(&mut a, &mut m);
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std::mem::swap(&mut x0, &mut inv);
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}
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if inv < Zero::zero() {
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inv += m0.clone()
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}
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inv
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}
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pub fn modinv_v3(a: &BigInt, q: &BigInt) -> BigInt {
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let mut aa: BigInt = a.clone();
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let mut qq: BigInt = q.clone();
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if qq < Zero::zero() {
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qq = -qq;
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}
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if aa < Zero::zero() {
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aa = -aa;
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}
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let d = num::Integer::gcd(&aa, &qq);
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if d != One::one() {
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println!("ERR no mod_inv");
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}
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let res: BigInt;
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if d < Zero::zero() {
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res = d + qq;
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} else {
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res = d;
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}
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res
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}
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pub fn modinv_v4(x: &BigInt, q: &BigInt) -> BigInt {
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let (gcd, inverse, _) = extended_gcd(x.clone(), q.clone());
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let one: BigInt = One::one();
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if gcd == one {
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modulus(&inverse, q)
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} else {
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panic!("error: gcd!=one")
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}
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}
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pub fn extended_gcd(a: BigInt, b: BigInt) -> (BigInt, BigInt, BigInt) {
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let (mut s, mut old_s) = (BigInt::zero(), BigInt::one());
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let (mut t, mut old_t) = (BigInt::one(), BigInt::zero());
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let (mut r, mut old_r) = (b, a);
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while r != BigInt::zero() {
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let quotient = &old_r / &r;
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old_r -= "ient * &r;
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std::mem::swap(&mut old_r, &mut r);
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old_s -= "ient * &s;
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std::mem::swap(&mut old_s, &mut s);
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old_t -= quotient * &t;
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std::mem::swap(&mut old_t, &mut t);
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}
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let _quotients = (t, s); // == (a, b) / gcd
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(old_r, old_s, old_t)
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}
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*/
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pub fn concatenate_arrays<T: Clone>(x: &[T], y: &[T]) -> Vec<T> {
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x.iter().chain(y).cloned().collect()
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}
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#[allow(clippy::many_single_char_names)]
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pub fn modsqrt(a: &BigInt, q: &BigInt) -> Result<BigInt, String> {
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// Tonelli-Shanks Algorithm (https://en.wikipedia.org/wiki/Tonelli%E2%80%93Shanks_algorithm)
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//
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// This implementation is following the Go lang core implementation https://golang.org/src/math/big/int.go?s=23173:23210#L859
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// Also described in https://www.maa.org/sites/default/files/pdf/upload_library/22/Polya/07468342.di020786.02p0470a.pdf
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// -> section 6
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let zero: BigInt = Zero::zero();
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let one: BigInt = One::one();
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if legendre_symbol(a, q) != 1 || a == &zero || q == &2.to_bigint().unwrap() {
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return Err("not a mod p square".to_string());
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} else if q % 4.to_bigint().unwrap() == 3.to_bigint().unwrap() {
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let r = a.modpow(&((q + one) / 4), q);
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return Ok(r);
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}
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let mut s = q - &one;
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let mut e: BigInt = Zero::zero();
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while &s % 2 == zero {
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s >>= 1;
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e += &one;
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}
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let mut n: BigInt = 2.to_bigint().unwrap();
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while legendre_symbol(&n, q) != -1 {
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n = &n + &one;
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}
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let mut y = a.modpow(&((&s + &one) >> 1), q);
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let mut b = a.modpow(&s, q);
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let mut g = n.modpow(&s, q);
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let mut r = e;
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loop {
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let mut t = b.clone();
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let mut m: BigInt = Zero::zero();
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while t != one {
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t = modulus(&(&t * &t), q);
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m += &one;
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}
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if m == zero {
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return Ok(y);
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}
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t = g.modpow(&(2.to_bigint().unwrap().modpow(&(&r - &m - 1), q)), q);
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g = g.modpow(&(2.to_bigint().unwrap().modpow(&(r - &m), q)), q);
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y = modulus(&(y * t), q);
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b = modulus(&(b * &g), q);
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r = m.clone();
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}
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}
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#[allow(dead_code)]
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#[allow(clippy::many_single_char_names)]
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pub fn modsqrt_v2(a: &BigInt, q: &BigInt) -> Result<BigInt, String> {
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// Tonelli-Shanks Algorithm (https://en.wikipedia.org/wiki/Tonelli%E2%80%93Shanks_algorithm)
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//
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// This implementation is following this Python implementation by Dusk https://github.com/dusk-network/dusk-zerocaf/blob/master/tools/tonelli.py
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let zero: BigInt = Zero::zero();
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let one: BigInt = One::one();
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if legendre_symbol(a, q) != 1 || a == &zero || q == &2.to_bigint().unwrap() {
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return Err("not a mod p square".to_string());
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} else if q % 4.to_bigint().unwrap() == 3.to_bigint().unwrap() {
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let r = a.modpow(&((q + one) / 4), q);
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return Ok(r);
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}
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let mut p = q - &one;
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let mut s: BigInt = Zero::zero();
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while &p % 2.to_bigint().unwrap() == zero {
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s += &one;
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p >>= 1;
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}
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let mut z: BigInt = One::one();
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while legendre_symbol(&z, q) != -1 {
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z = &z + &one;
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}
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let mut c = z.modpow(&p, q);
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let mut x = a.modpow(&((&p + &one) >> 1), q);
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let mut t = a.modpow(&p, q);
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let mut m = s;
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while t != one {
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let mut i: BigInt = One::one();
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let mut e: BigInt = 2.to_bigint().unwrap();
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while i < m {
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if t.modpow(&e, q) == one {
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break;
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}
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e *= 2.to_bigint().unwrap();
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i += &one;
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}
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let b = c.modpow(&(2.to_bigint().unwrap().modpow(&(&m - &i - 1), q)), q);
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x = modulus(&(x * &b), q);
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t = modulus(&(t * &b * &b), q);
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c = modulus(&(&b * &b), q);
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m = i.clone();
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}
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Ok(x)
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}
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pub fn legendre_symbol(a: &BigInt, q: &BigInt) -> i32 {
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// returns 1 if has a square root modulo q
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let one: BigInt = One::one();
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let ls: BigInt = a.modpow(&((q - &one) >> 1), q);
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if ls == q - one {
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return -1;
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}
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1
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_mod_inverse() {
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let a = BigInt::parse_bytes(b"123456789123456789123456789123456789123456789", 10).unwrap();
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let b = BigInt::parse_bytes(b"12345678", 10).unwrap();
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assert_eq!(
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modinv(&a, &b).unwrap(),
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BigInt::parse_bytes(b"641883", 10).unwrap()
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);
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}
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#[test]
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fn test_sqrtmod() {
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let a = BigInt::parse_bytes(
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b"6536923810004159332831702809452452174451353762940761092345538667656658715568",
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10,
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)
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.unwrap();
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let q = BigInt::parse_bytes(
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b"7237005577332262213973186563042994240857116359379907606001950938285454250989",
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10,
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)
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.unwrap();
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assert_eq!(
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(modsqrt(&a, &q).unwrap()).to_string(),
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"5464794816676661649783249706827271879994893912039750480019443499440603127256"
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);
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assert_eq!(
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(modsqrt_v2(&a, &q).unwrap()).to_string(),
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"5464794816676661649783249706827271879994893912039750480019443499440603127256"
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);
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}
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}
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