feat: bls signer abstraction

crypto/bls/attestation.go

@@ -13,7 +13,10 @@ import (
 	"github.com/consensys/gnark-crypto/ecc/bn254"
 	"github.com/consensys/gnark-crypto/ecc/bn254/fp"
 	"github.com/consensys/gnark-crypto/ecc/bn254/fr"
+
 	"github.com/ethereum/go-ethereum/accounts/keystore"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/crypto"
 )
 
 // We are using similar structure for saving bls keys as ethereum keystore
@@ -282,3 +285,12 @@ func (k *KeyPair) GetPubKeyG2() *G2Point {
 func (k *KeyPair) GetPubKeyG1() *G1Point {
 	return k.PubKey
 }
+
+// GetOperatorID hashes the G1Point (public key of an operator) to generate the operator ID.
+// It does it to match how it's hashed in solidity: `keccak256(abi.encodePacked(pk.X, pk.Y))`
+// Ref: https://github.com/Layr-Labs/eigenlayer-contracts/blob/avs-unstable/src/contracts/libraries/BN254.sol#L285
+func (p *G1Point) GetOperatorID() string {
+	x := p.X.BigInt(new(big.Int))
+	y := p.Y.BigInt(new(big.Int))
+	return crypto.Keccak256Hash(append(math.U256Bytes(x), math.U256Bytes(y)...)).Hex()
+}

signer/bls/cerberus/cerberus.go

@@ -0,0 +1,93 @@
+package cerberus
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"log"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+
+	sdkBls "github.com/Layr-Labs/eigensdk-go/crypto/bls"
+	"github.com/Layr-Labs/eigensdk-go/signer/bls/types"
+
+	v1 "github.com/Layr-Labs/cerberus-api/pkg/api/v1"
+)
+
+type Config struct {
+	URL          string
+	PublicKeyHex string
+
+	// Optional: in case if your signer uses local keystore
+	Password string
+
+	EnableTLS       bool
+	TLSCertFilePath string
+
+	SigningTimeout time.Duration
+}
+
+type Signer struct {
+	client    v1.SignerClient
+	pubKeyHex string
+	password  string
+}
+
+func New(cfg Config) (Signer, error) {
+	opts := make([]grpc.DialOption, 0)
+	if cfg.EnableTLS {
+		creds, err := credentials.NewClientTLSFromFile(cfg.TLSCertFilePath, "")
+		if err != nil {
+			log.Fatalf("could not load tls cert: %s", err)
+		}
+		opts = append(opts, grpc.WithTransportCredentials(creds))
+	}
+
+	conn, err := grpc.NewClient(cfg.URL, opts...)
+	if err != nil {
+		log.Fatalf("did not connect: %v", err)
+	}
+
+	client := v1.NewSignerClient(conn)
+	return Signer{
+		client:    client,
+		pubKeyHex: cfg.PublicKeyHex,
+		password:  cfg.Password,
+	}, nil
+}
+
+func (s Signer) Sign(ctx context.Context, msg []byte) ([]byte, error) {
+	if len(msg) != 32 {
+		return nil, types.ErrInvalidMessageLength
+	}
+
+	var data [32]byte
+	copy(data[:], msg)
+
+	resp, err := s.client.SignGeneric(ctx, &v1.SignGenericRequest{
+		Data:      data[:],
+		PublicKey: s.pubKeyHex,
+		Password:  s.password,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return resp.Signature, nil
+}
+
+func (s Signer) GetOperatorId() (string, error) {
+	pkBytes, err := hex.DecodeString(s.pubKeyHex)
+	if err != nil {
+		return "", fmt.Errorf("failed to decode BLS public key: %w", err)
+	}
+	pubkey := new(sdkBls.G1Point)
+	publicKey := pubkey.Deserialize(pkBytes)
+	return publicKey.GetOperatorID(), nil
+}
+
+func (s Signer) GetPublicKeyHex() string {
+	return s.pubKeyHex
+}

signer/bls/local/local.go

@@ -0,0 +1,47 @@
+package local
+
+import (
+	"context"
+	"encoding/hex"
+
+	sdkBls "github.com/Layr-Labs/eigensdk-go/crypto/bls"
+	"github.com/Layr-Labs/eigensdk-go/signer/bls/types"
+)
+
+type Config struct {
+	Path     string
+	Password string
+}
+
+type Signer struct {
+	key *sdkBls.KeyPair
+}
+
+func New(cfg Config) (*Signer, error) {
+	keyPair, err := sdkBls.ReadPrivateKeyFromFile(cfg.Path, cfg.Password)
+	if err != nil {
+		return nil, err
+	}
+	return &Signer{
+		key: keyPair,
+	}, nil
+}
+
+func (s Signer) Sign(ctx context.Context, msg []byte) ([]byte, error) {
+	if len(msg) != 32 {
+		return nil, types.ErrInvalidMessageLength
+	}
+
+	var data [32]byte
+	copy(data[:], msg)
+
+	return s.key.SignMessage(data).Serialize(), nil
+}
+
+func (s Signer) GetOperatorId() (string, error) {
+	return s.key.PubKey.GetOperatorID(), nil
+}
+
+func (s Signer) GetPublicKeyHex() string {
+	return hex.EncodeToString(s.key.PubKey.Serialize())
+}