add random point functions

Cargo.lock

@@ -86,6 +86,7 @@ dependencies = [
  "autocfg",
  "num-integer",
  "num-traits",
+ "rand",
 ]
 
 [[package]]

Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 bitvec = "1"
 hex = "0.4.3"
 nom = "7.1.1"
-num-bigint = "0.4.3"
+num-bigint = { version = "0.4.3", features = ["rand"] }
 num-traits = "0.2"
 once_cell = "1.18.0"
 rand = "0.8.5"

README.md

@@ -13,6 +13,8 @@ To build a zk library from scratch keeping the implementation as easily understa
 - Ed25519 public key generation, signing and signature verification on Curve25519 curve
 - Bulletproofs (inner product argument range proof)
 - Pinnocio (equation parser, R1CS, QAP)
+- Miller's Algorithm
+- Weil Pairing on BLS12-381
 
 ## What's NOT implemented so far
 - Big number

src/building_block/curves/bls12_381/g1_point.rs

@@ -11,7 +11,11 @@ use crate::{
     zero::Zero,
   },
 };
-use num_bigint::BigUint;
+use num_bigint::{
+  BigUint,
+  RandBigInt,
+};
+use num_traits::Zero as NumTraitsZero;
 use std::{
   fmt,
   ops::{Add, Mul, Neg},
@@ -87,6 +91,12 @@ impl G1Point {
       &ns[80..96],
     )
   }
+
+  pub fn get_random_point() -> AffinePoint {
+    let mut rng = rand::thread_rng();
+    let n = rng.gen_biguint_range(&NumTraitsZero::zero(), &CURVE_GROUP.order);
+    G1Point::g() * &CURVE_GROUP.elem(&n)
+  }
 }
 
 impl RationalPoint for G1Point {

src/building_block/curves/bls12_381/g2_point.rs

@@ -13,7 +13,11 @@ use crate::{
     zero::Zero,
   },
 };
-use num_bigint::BigUint;
+use num_bigint::{
+  BigUint,
+  RandBigInt,
+};
+use num_traits::Zero as NumTraitsZero;
 use std::{
   ops::{Add, Mul, Neg},
   sync::Arc,
@@ -62,6 +66,12 @@ impl G2Point {
       G2Point::Rational { x, y } => G2Point::new(&x, &y.inv()),
     }
   }
+
+  pub fn get_random_point() -> AffinePoint {
+    let mut rng = rand::thread_rng();
+    let n = rng.gen_biguint_range(&NumTraitsZero::zero(), &CURVE_GROUP.order);
+    G2Point::g() * &CURVE_GROUP.elem(&n)
+  }
 }
 
 macro_rules! impl_neg {

src/building_block/curves/bls12_381/weil_pairing.rs

@@ -81,31 +81,53 @@ impl WeilPairing {
 mod tests {
   use super::*;
 
-  #[test]
-  fn do_it() {
-    let wp = WeilPairing::new();
-
-    let p = G1Point::g();
-    let p2 = &p + &p;
-    let q = G2Point::g();
+  fn test_pairing(wp: &WeilPairing, p: &G1Point, q: &G2Point) -> bool {
+    let p2 = p + p;
 
     // test e(p + p2, q) = e(p, q) e(p2, q)
 
-    println!("Calculating e(p + p2, q)...");
-    let lhs = wp.calculate(&(&p + &p2), &q);
+    // println!("Calculating e(p + p2, q)...");
+    let lhs = wp.calculate(&(p + &p2), q);
 
-    println!("Calculating e(p, q)...");
-    let rhs1 = wp.calculate(&p, &q);
+    // println!("Calculating e(p, q)...");
+    let rhs1 = wp.calculate(p, q);
 
-    println!("Calculating e(p2, q)...");
-    let rhs2 = wp.calculate(&p2, &q);
+    // println!("Calculating e(p2, q)...");
+    let rhs2 = wp.calculate(&p2, q);
 
     let rhs = rhs1 * rhs2;
 
-    println!("lhs = {:?}", &lhs);
-    println!("rhs = {:?}", &rhs);
+    // println!("lhs = {:?}", &lhs);
+    // println!("rhs = {:?}", &rhs);
 
-    assert!(lhs == rhs);
+    lhs == rhs
+  }
+
+  #[test]
+  fn test_pairing_with_generators() {
+    let wp = WeilPairing::new();
+    let p = G1Point::g();
+    let q = G2Point::g();
+    let res = test_pairing(&wp, &p, &q);
+    assert!(res);
+  }
+
+  //#[test]
+  fn test_pairing_with_random_points() {
+    let mut errors = 0;
+
+    for i in 0..1000 {
+      println!("iteration {}", i);
+      let wp = WeilPairing::new();
+      let p = G1Point::get_random_point();
+      let q = G2Point::get_random_point();
+      let res = test_pairing(&wp, &p, &q);
+      if res == false {
+        println!("----> iteration {} failed!", i);
+        errors += 1;
+      }
+    }
+    println!("{} tests failed!", errors);
   }
 }