feat(bls): add signing functions (#817)

src/crypto/bls.spec.ts

@@ -30,13 +30,26 @@ describe('bls', () => {
     expect(bls.signatureToBytes(sig)).toEqual(hexToBuffer(sigStr));
   });
 
+  it('generates signature correctly', async () => {
+    const sk = bls.secretKeyFromBytes(skStr);
+    expect(bls.sign(msg, sk)).toEqual(hexToBuffer(sigStr));
+  });
+
   it('verifies signature correctly', async () => {
     const pk = bls.publicKeyFromBytes(pkStr);
     const sig = bls.signatureFromBytes(hexToBuffer(sigStr));
 
     expect(bls.verify(pk, sig, msg)).toEqual(true);
   });
 
+  it('generates proof of possession correctly', async () => {
+    const sk = bls.secretKeyFromBytes(skStr);
+    const pk = bls.publicKeyFromBytes(pkStr);
+    const pkBytes = bls.publicKeyToBytes(pk);
+
+    expect(bls.signProofOfPossession(pkBytes, sk)).toEqual(hexToBuffer(popStr));
+  });
+
   it('verifies proof of possession correctly', async () => {
     const pk = bls.publicKeyFromBytes(pkStr);
     const pop = bls.signatureFromBytes(hexToBuffer(popStr));

src/crypto/bls.ts

@@ -56,3 +56,22 @@ export function verifyProofOfPossession(
     DST: proofOfPossessionDST,
   });
 }
+
+export function sign(msg: Uint8Array | string, sk: SecretKey): Uint8Array {
+  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+  // @ts-expect-error Will error until a version of @noble/curves is released with https://github.com/paulmillr/noble-curves/pull/117
+  return bls12_381.sign(msg, sk, {
+    DST: signatureDST,
+  });
+}
+
+export function signProofOfPossession(
+  msg: Uint8Array | string,
+  sk: SecretKey,
+): Uint8Array {
+  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+  // @ts-expect-error Will error until a version of @noble/curves is released with https://github.com/paulmillr/noble-curves/pull/117
+  return bls12_381.sign(msg, sk, {
+    DST: proofOfPossessionDST,
+  });
+}