be able to use BLS keys as ECIES keys

MystenLabs · Oct 2, 2023 · 5b44157 · 5b44157
1 parent 6315731
commit 5b44157
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Showing 3 changed files with 30 additions and 1 deletion.
diff --git a/fastcrypto-tbls/src/ecies.rs b/fastcrypto-tbls/src/ecies.rs
@@ -58,6 +58,10 @@ where
         Self(G::ScalarType::rand(rng))
     }
 
+    pub fn from(sc: G::ScalarType) -> Self {
+        Self(sc)
+    }
+
     pub fn decrypt(&self, enc: &Encryption<G>) -> Vec<u8> {
         enc.decrypt(&self.0)
     }
@@ -112,6 +116,12 @@ where
     }
 }
 
+impl<G: GroupElement> From<G> for PublicKey<G> {
+    fn from(p: G) -> Self {
+        Self(p)
+    }
+}
+
 impl<G: GroupElement + Serialize> Encryption<G> {
     fn deterministic_encrypt(msg: &[u8], r_g: &G, r_x_g: &G) -> Self {
         let hkdf_result = Self::hkdf(r_x_g);

diff --git a/fastcrypto-tbls/src/tests/ecies_tests.rs b/fastcrypto-tbls/src/tests/ecies_tests.rs
@@ -3,7 +3,11 @@
 
 use crate::ecies::*;
 use crate::random_oracle::RandomOracle;
+use fastcrypto::bls12381::min_sig::BLS12381KeyPair;
+use fastcrypto::groups::bls12381::{G2Element, Scalar};
 use fastcrypto::groups::ristretto255::RistrettoPoint;
+use fastcrypto::groups::GroupElement;
+use fastcrypto::traits::KeyPair;
 use rand::thread_rng;
 
 const MSG: &[u8; 4] = b"test";
@@ -42,3 +46,18 @@ fn test_recovery_package() {
         .decrypt_with_recovery_package(&pkg, &ro, &encryption)
         .is_err());
 }
+
+#[test]
+fn test_blskeypair_to_group() {
+    let pair = BLS12381KeyPair::generate(&mut thread_rng());
+    let (pk, sk) = (pair.public().clone(), pair.private());
+    let pk: G2Element = bcs::from_bytes(pk.as_ref()).expect("should work");
+    let ecies_pk = PublicKey::<G2Element>::from(pk);
+    let sk: Scalar = bcs::from_bytes(sk.as_ref()).expect("should work");
+    let ecies_sk = PrivateKey::<G2Element>::from(sk);
+    assert_eq!(
+        ecies_pk,
+        PublicKey::<G2Element>::from_private_key(&ecies_sk)
+    );
+    assert_eq!(*ecies_pk.as_element(), G2Element::generator() * sk);
+}
diff --git a/fastcrypto/src/groups/bls12381.rs b/fastcrypto/src/groups/bls12381.rs
@@ -652,7 +652,7 @@ impl ScalarType for Scalar {
 impl FiatShamirChallenge for Scalar {
     fn fiat_shamir_reduction_to_group_element(uniform_buffer: &[u8]) -> Self {
         const INPUT_LENGTH: usize = SCALAR_LENGTH - 10; // Safe for our prime field
-        assert!(INPUT_LENGTH >= uniform_buffer.len());
+        assert!(INPUT_LENGTH <= uniform_buffer.len());
         let mut bytes = [0u8; INPUT_LENGTH];
         bytes.copy_from_slice(&uniform_buffer[..INPUT_LENGTH]);
         let mut ret = blst_fr::default();