feat: use metadata field on certificate

agglayer/types.go

@@ -83,6 +83,7 @@ type Certificate struct {
 	NewLocalExitRoot    [32]byte              `json:"new_local_exit_root"`
 	BridgeExits         []*BridgeExit         `json:"bridge_exits"`
 	ImportedBridgeExits []*ImportedBridgeExit `json:"imported_bridge_exits"`
+	Metadata            common.Hash           `json:"metadata"`
 }
 
 // Hash returns a hash that uniquely identifies the certificate
@@ -110,6 +111,20 @@ func (c *Certificate) Hash() common.Hash {
 	)
 }
 
+// HashToSign is the actual hash that needs to be signed by the aggsender
+// as expected by the agglayer
+func (c *Certificate) HashToSign() common.Hash {
+	globalIndexHashes := make([][]byte, len(c.ImportedBridgeExits))
+	for i, importedBridgeExit := range c.ImportedBridgeExits {
+		globalIndexHashes[i] = importedBridgeExit.GlobalIndex.Hash().Bytes()
+	}
+
+	return crypto.Keccak256Hash(
+		c.NewLocalExitRoot[:],
+		crypto.Keccak256Hash(globalIndexHashes...).Bytes(),
+	)
+}
+
 // SignedCertificate is the struct that contains the certificate and the signature of the signer
 type SignedCertificate struct {
 	*Certificate
@@ -138,7 +153,10 @@ type GlobalIndex struct {
 
 func (g *GlobalIndex) Hash() common.Hash {
 	return crypto.Keccak256Hash(
-		bridgesync.GenerateGlobalIndex(g.MainnetFlag, g.RollupIndex, g.LeafIndex).Bytes())
+		cdkcommon.AsLittleEndianSlice(
+			bridgesync.GenerateGlobalIndex(g.MainnetFlag, g.RollupIndex, g.LeafIndex),
+		),
+	)
 }
 
 // BridgeExit represents a token bridge exit
@@ -379,6 +397,7 @@ type CertificateHeader struct {
 	CertificateID    common.Hash       `json:"certificate_id"`
 	NewLocalExitRoot common.Hash       `json:"new_local_exit_root"`
 	Status           CertificateStatus `json:"status"`
+	Metadata         common.Hash       `json:"metadata"`
 }
 
 func (c CertificateHeader) String() string {

aggsender/aggsender.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"math/big"
 	"os"
 	"time"
 
@@ -153,7 +154,7 @@ func (a *AggSender) sendCertificate(ctx context.Context) error {
 
 	a.log.Infof("building certificate for block: %d to block: %d", fromBlock, toBlock)
 
-	certificate, err := a.buildCertificate(ctx, bridges, claims, lastSentCertificateInfo)
+	certificate, err := a.buildCertificate(ctx, bridges, claims, lastSentCertificateInfo, toBlock)
 	if err != nil {
 		return fmt.Errorf("error building certificate: %w", err)
 	}
@@ -209,7 +210,8 @@ func (a *AggSender) saveCertificateToFile(signedCertificate *agglayer.SignedCert
 func (a *AggSender) buildCertificate(ctx context.Context,
 	bridges []bridgesync.Bridge,
 	claims []bridgesync.Claim,
-	lastSentCertificateInfo aggsendertypes.CertificateInfo) (*agglayer.Certificate, error) {
+	lastSentCertificateInfo aggsendertypes.CertificateInfo,
+	toBlock uint64) (*agglayer.Certificate, error) {
 	if len(bridges) == 0 && len(claims) == 0 {
 		return nil, errNoBridgesAndClaims
 	}
@@ -245,6 +247,7 @@ func (a *AggSender) buildCertificate(ctx context.Context,
 		BridgeExits:         bridgeExits,
 		ImportedBridgeExits: importedBridgeExits,
 		Height:              height,
+		Metadata:            createCertificateMetadata(toBlock),
 	}, nil
 }
 
@@ -412,13 +415,19 @@ func (a *AggSender) getImportedBridgeExits(
 
 // signCertificate signs a certificate with the sequencer key
 func (a *AggSender) signCertificate(certificate *agglayer.Certificate) (*agglayer.SignedCertificate, error) {
-	hashToSign := certificate.Hash()
+	hashToSign := certificate.HashToSign()
 
 	sig, err := crypto.Sign(hashToSign.Bytes(), a.sequencerKey)
 	if err != nil {
 		return nil, err
 	}
 
+	a.log.Infof("Signed certificate. sequencer address: %s. New local exit root: %s Hash signed: %s",
+		crypto.PubkeyToAddress(a.sequencerKey.PublicKey).String(),
+		common.BytesToHash(certificate.NewLocalExitRoot[:]).String(),
+		hashToSign.String(),
+	)
+
 	r, s, isOddParity, err := extractSignatureData(sig)
 	if err != nil {
 		return nil, err
@@ -500,3 +509,8 @@ func extractSignatureData(signature []byte) (r, s common.Hash, isOddParity bool,
 
 	return
 }
+
+// createCertificateMetadata creates a certificate metadata from given input
+func createCertificateMetadata(toBlock uint64) common.Hash {
+	return common.BigToHash(new(big.Int).SetUint64(toBlock))
+}

aggsender/aggsender_test.go

@@ -493,6 +493,7 @@ func TestBuildCertificate(t *testing.T) {
 		bridges                 []bridgesync.Bridge
 		claims                  []bridgesync.Claim
 		lastSentCertificateInfo aggsendertypes.CertificateInfo
+		toBlock                 uint64
 		mockFn                  func()
 		expectedCert            *agglayer.Certificate
 		expectedError           bool
@@ -532,10 +533,12 @@ func TestBuildCertificate(t *testing.T) {
 				NewLocalExitRoot: common.HexToHash("0x123"),
 				Height:           1,
 			},
+			toBlock: 10,
 			expectedCert: &agglayer.Certificate{
 				NetworkID:         1,
 				PrevLocalExitRoot: common.HexToHash("0x123"),
 				NewLocalExitRoot:  common.HexToHash("0x789"),
+				Metadata:          createCertificateMetadata(10),
 				BridgeExits: []*agglayer.BridgeExit{
 					{
 						LeafType: agglayer.LeafTypeAsset,
@@ -686,7 +689,7 @@ func TestBuildCertificate(t *testing.T) {
 				l1infoTreeSyncer: mockL1InfoTreeSyncer,
 				log:              log.WithFields("test", "unittest"),
 			}
-			cert, err := aggSender.buildCertificate(context.Background(), tt.bridges, tt.claims, tt.lastSentCertificateInfo)
+			cert, err := aggSender.buildCertificate(context.Background(), tt.bridges, tt.claims, tt.lastSentCertificateInfo, tt.toBlock)
 
 			if tt.expectedError {
 				require.Error(t, err)

common/common.go

@@ -109,3 +109,19 @@ func NewKeyFromKeystore(cfg types.KeystoreFileConfig) (*ecdsa.PrivateKey, error)
 	}
 	return key.PrivateKey, nil
 }
+
+// AsLittleEndianSlice converts a big.Int to a 32-byte little-endian representation.
+func AsLittleEndianSlice(n *big.Int) []byte {
+	// Get the absolute value in big-endian byte slice
+	beBytes := n.Bytes()
+
+	// Initialize a 32-byte array for the result
+	leBytes := make([]byte, 32)
+
+	// Fill the array in reverse order to convert to little-endian
+	for i := 0; i < len(beBytes) && i < 32; i++ {
+		leBytes[i] = beBytes[len(beBytes)-1-i]
+	}
+
+	return leBytes
+}

common/common_test.go

@@ -0,0 +1,59 @@
+package common
+
+import (
+	"math/big"
+	"testing"
+)
+
+func TestAsLittleEndianSlice(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name     string
+		input    *big.Int
+		expected []byte
+	}{
+		{
+			name:     "Zero value",
+			input:    big.NewInt(0),
+			expected: make([]byte, 32),
+		},
+		{
+			name:     "Positive value",
+			input:    big.NewInt(123456789),
+			expected: append([]byte{21, 205, 91, 7}, make([]byte, 28)...),
+		},
+		{
+			name:     "Negative value",
+			input:    big.NewInt(-123456789),
+			expected: append([]byte{21, 205, 91, 7}, make([]byte, 28)...),
+		},
+		{
+			name: "Large positive value",
+			input: new(big.Int).SetBytes([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}),
+			expected: []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+				0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			result := AsLittleEndianSlice(tt.input)
+			if len(result) != 32 {
+				t.Errorf("expected length 32, got %d", len(result))
+			}
+			for i := range result {
+				if result[i] != tt.expected[i] {
+					t.Errorf("expected byte at index %d to be %x, got %x", i, tt.expected[i], result[i])
+				}
+			}
+		})
+	}
+}