Use jacobi function in rust-tapyrus

chaintope · Aug 6, 2020 · 0aa16ad · 0aa16ad
1 parent ed1597b
commit 0aa16ad
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Showing 2 changed files with 8 additions and 57 deletions.
diff --git a/src/crypto/vss.rs b/src/crypto/vss.rs
@@ -11,7 +11,7 @@ use crate::signer_node::BidirectionalSharedSecretMap;
 use crate::signer_node::SharedSecretMap;
 use crate::signer_node::ToSharedSecretMap;
 use crate::signer_node::ToVerifiableSS;
-use crate::util::jacobi;
+
 use curv::arithmetic::traits::Converter;
 use curv::cryptographic_primitives::secret_sharing::feldman_vss::VerifiableSS;
 use curv::elliptic::curves::traits::ECScalar;
@@ -24,6 +24,7 @@ use std::io;
 use std::str::FromStr;
 use tapyrus::blockdata::block::Block;
 use tapyrus::consensus::encode::{self, *};
+use tapyrus::util::prime::jacobi;
 use tapyrus::{PrivateKey, PublicKey};
 
 // | name                 | size      | explaination                                                                                      |
@@ -139,12 +140,11 @@ impl Vss {
             block.header.signature_hash(),
         );
 
-        let p = BigInt::from_str_radix(
-            "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F",
-            16,
-        )
-        .unwrap();
-        let is_positive = jacobi(&shared_keys_for_positive.y.y_coor().unwrap(), &p) == 1;
+        let y = shared_keys_for_positive
+            .y
+            .y_coor()
+            .expect("can not get y_coor");
+        let is_positive = jacobi(&Converter::to_vec(&y)) == 1;
         let (shared_keys, local_sig) = if is_positive {
             (shared_keys_for_positive, local_sig_for_positive)
         } else {

diff --git a/src/util.rs b/src/util.rs
@@ -1,4 +1,4 @@
-use curv::{BigInt, GE};
+use curv::GE;
 use std::convert::TryFrom;
 use std::os::raw::c_int;
 use std::sync::atomic::AtomicUsize;
@@ -11,48 +11,6 @@ pub fn sum_point(points: &Vec<GE>) -> GE {
     tail.fold(head.clone(), |acc, x| acc + x)
 }
 
-pub fn jacobi(a: &BigInt, n: &BigInt) -> i8 {
-    assert!(*n >= BigInt::from(3));
-    assert!(a < n);
-
-    if a.is_zero() {
-        return 0;
-    }
-    if *a == BigInt::from(1) {
-        return 1;
-    }
-
-    let mut a1: BigInt = a.clone();
-    let mut e = 0;
-    while a1.is_multiple_of(&BigInt::from(2)) {
-        a1 = a1 >> 1;
-        e += 1;
-    }
-    let mut s: i8 = if e & 1 == 0
-        || n.modulus(&BigInt::from(8)) == BigInt::from(1)
-        || n.modulus(&BigInt::from(8)) == BigInt::from(7)
-    {
-        1
-    } else if n.modulus(&BigInt::from(8)) == BigInt::from(3)
-        || n.modulus(&BigInt::from(8)) == BigInt::from(5)
-    {
-        -1
-    } else {
-        0
-    };
-    if n.modulus(&BigInt::from(4)) == BigInt::from(3)
-        && a1.modulus(&BigInt::from(4)) == BigInt::from(3)
-    {
-        s = -s
-    }
-
-    if a1 == BigInt::from(1) {
-        s
-    } else {
-        s * jacobi(&(n % a1.clone()), &a1.clone())
-    }
-}
-
 const STOP_SIGNALS: [usize; 6] = [
     signal_hook::SIGABRT as usize,
     signal_hook::SIGHUP as usize,
@@ -117,13 +75,6 @@ mod tests {
         assert_eq!(sum, p6);
     }
 
-    #[test]
-    fn test_jacobi() {
-        assert_eq!(jacobi(&BigInt::from(158), &BigInt::from(235)), -1);
-        assert_eq!(jacobi(&BigInt::from(5), &BigInt::from(12)), -1);
-        assert_eq!(jacobi(&BigInt::from(16), &BigInt::from(60)), 1);
-    }
-
     #[test]
     fn test_signals() {
         let handler = set_stop_signal_handler().unwrap();