bls: support gen pub key

Signed-off-by: Ignacio Hagopian <jsign.uy@gmail.com>

bls/bls.go

@@ -5,6 +5,7 @@ import (
 
 	curve12381 "github.com/drand/kyber-bls12381"
 	"github.com/drand/kyber/sign/bls" // nolint:staticcheck
+	"github.com/filecoin-project/go-address"
 )
 
 // Sign creates a BLS signature of a message using a private key.
@@ -40,3 +41,25 @@ func Verify(pubkey, msg, sig []byte) bool {
 
 	return true
 }
+
+// GetPubKey returns the public key from the private key.
+func GetPubKey(pk []byte) (address.Address, error) {
+	var pkrev [32]byte
+	for i := 0; i < 32; i++ {
+		pkrev[i] = pk[32-i-1]
+	}
+	scalar := curve12381.NewKyberScalar().SetBytes(pkrev[:])
+	pubPoint := curve12381.NewGroupG1().Point()
+	pubPoint.Mul(scalar, nil)
+
+	buf, err := pubPoint.MarshalBinary()
+	if err != nil {
+		return address.Address{}, fmt.Errorf("marshaling pub: %s", err)
+	}
+	addr, err := address.NewBLSAddress(buf)
+	if err != nil {
+		return address.Undef, fmt.Errorf("generating public key: %s", err)
+	}
+
+	return addr, nil
+}

wallet/wallet.go

@@ -72,8 +72,7 @@ func PublicKey(lotusExportedPK string) (address.Address, error) {
 	case types.KTSecp256k1:
 		return secp256k1.GetPubKey(ki.PrivateKey)
 	default:
-		// TODO: support BLS.
-		return address.Undef, fmt.Errorf("signature type not supported")
+		return bls.GetPubKey(ki.PrivateKey)
 	}
 }
 

wallet/wallet_test.go

@@ -61,7 +61,7 @@ func TestSecp256k1(t *testing.T) {
 	t.Run("gen-pubkey", func(t *testing.T) {
 		addr, err := PublicKey(privateKeyHex)
 		require.NoError(t, err)
-		require.Equal(t, "f1fib3pv7jua2ockdugtz7viz3cyy6lkhh7rfx3sa", addr.String())
+		require.Equal(t, publicAddr, addr.String())
 	})
 }
 
@@ -88,6 +88,12 @@ func TestBLSSign(t *testing.T) {
 		require.Equal(t, hexSignature, genHexSignature)
 	})
 
+	t.Run("gen-pubkey", func(t *testing.T) {
+		addr, err := PublicKey(privateKeyHex)
+		require.NoError(t, err)
+		require.Equal(t, publicAddr, addr.String())
+	})
+
 	t.Run("verify", func(t *testing.T) {
 		t.Parallel()