[payments] disperser server metering (#792)

api/proto/disperser/disperser.proto

@@ -101,22 +101,10 @@ message DisperseBlobRequest {
 }
 
 message DispersePaidBlobRequest {
-	// The data to be dispersed.
-	// The size of data must be <= 2MiB. Every 32 bytes of data chunk is interpreted as an integer in big endian format
-	// where the lower address has more significant bits. The integer must stay in the valid range to be interpreted
-	// as a field element on the bn254 curve. The valid range is 
-	// 0 <= x < 21888242871839275222246405745257275088548364400416034343698204186575808495617
-	// containing slightly less than 254 bits and more than 253 bits. If any one of the 32 bytes chunk is outside the range, 
-	// the whole request is deemed as invalid, and rejected. 
-	// NOTE: I want to include dataLength here, not the data itself.
+	// The data to be dispersed. Same requirements as DisperseBlobRequest.
 	bytes data = 1;
-	// The quorums to which the blob will be sent, in addition to the required quorums which are configured
-	// on the EigenDA smart contract. If required quorums are included here, an error will be returned.
-	// The disperser will ensure that the encoded blobs for each quorum are all processed
-	// within the same batch. The request doesn't need to include the payment split because the information is registered on-chain.
-	// In theory the quorum numbers should be the same as the ones in the DisperseBlobRequest, but I'm allowing freedom 
-	// for individual requests.
-	repeated uint32 custom_quorum_numbers = 2;
+	// The quorums to which the blob to be sent
+	repeated uint32 quorum_numbers = 2;
 
 	// Payment header contains AccountID, BinIndex, and CumulativePayment
 	common.PaymentHeader payment_header = 3;

core/auth.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 
+	commonpb "github.com/Layr-Labs/eigenda/api/grpc/common"
 	geth "github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -47,5 +48,9 @@ func VerifySignature(message []byte, accountAddr geth.Address, sig []byte) error
 	}
 
 	return nil
+}
 
+type PaymentSigner interface {
+	SignBlobPayment(header *commonpb.PaymentHeader) ([]byte, error)
+	GetAccountID() string
 }

core/auth/payment_signer.go

@@ -0,0 +1,98 @@
+package auth
+
+import (
+	"crypto/ecdsa"
+	"fmt"
+	"log"
+
+	commonpb "github.com/Layr-Labs/eigenda/api/grpc/common"
+	"github.com/Layr-Labs/eigenda/core"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+type PaymentSigner struct {
+	PrivateKey *ecdsa.PrivateKey
+}
+
+var _ core.PaymentSigner = &PaymentSigner{}
+
+func NewPaymentSigner(privateKeyHex string) *PaymentSigner {
+
+	privateKeyBytes := common.FromHex(privateKeyHex)
+	privateKey, err := crypto.ToECDSA(privateKeyBytes)
+	if err != nil {
+		log.Fatalf("Failed to parse private key: %v", err)
+	}
+
+	return &PaymentSigner{
+		PrivateKey: privateKey,
+	}
+}
+
+// SignBlobPayment signs the payment header and returns the signature
+func (s *PaymentSigner) SignBlobPayment(header *commonpb.PaymentHeader) ([]byte, error) {
+	header.AccountId = s.GetAccountID()
+	pm := core.ConvertPaymentHeader(header)
+	hash, err := pm.Hash()
+	if err != nil {
+		return nil, fmt.Errorf("failed to hash payment header: %v", err)
+	}
+
+	sig, err := crypto.Sign(hash[:], s.PrivateKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to sign hash: %v", err)
+	}
+
+	return sig, nil
+}
+
+type NoopPaymentSigner struct{}
+
+func NewNoopPaymentSigner() *NoopPaymentSigner {
+	return &NoopPaymentSigner{}
+}
+
+func (s *NoopPaymentSigner) SignBlobPayment(header *commonpb.PaymentHeader) ([]byte, error) {
+	return nil, fmt.Errorf("noop signer cannot sign blob payment header")
+}
+
+func (s *NoopPaymentSigner) GetAccountID() string {
+	return ""
+}
+
+// VerifyPaymentSignature verifies the signature against the payment metadata
+func VerifyPaymentSignature(paymentHeader *commonpb.PaymentHeader, paymentSignature []byte) bool {
+	pm := core.ConvertPaymentHeader(paymentHeader)
+	hash, err := pm.Hash()
+	if err != nil {
+		return false
+	}
+
+	recoveredPubKey, err := crypto.SigToPub(hash[:], paymentSignature)
+	if err != nil {
+		log.Printf("Failed to recover public key from signature: %v\n", err)
+		return false
+	}
+
+	recoveredAddress := crypto.PubkeyToAddress(*recoveredPubKey)
+	accountId := common.HexToAddress(paymentHeader.AccountId)
+	if recoveredAddress != accountId {
+		log.Printf("Signature address %s does not match account id %s\n", recoveredAddress.Hex(), accountId.Hex())
+		return false
+	}
+
+	return crypto.VerifySignature(
+		crypto.FromECDSAPub(recoveredPubKey),
+		hash[:],
+		paymentSignature[:len(paymentSignature)-1], // Remove recovery ID
+	)
+}
+
+// GetAccountID returns the Ethereum address of the signer
+func (s *PaymentSigner) GetAccountID() string {
+	publicKey := crypto.FromECDSAPub(&s.PrivateKey.PublicKey)
+	hash := crypto.Keccak256(publicKey[1:])
+
+	return common.BytesToAddress(hash[12:]).Hex()
+}

core/auth/payment_signer_test.go

@@ -0,0 +1,76 @@
+package auth_test
+
+import (
+	"encoding/hex"
+	"testing"
+
+	commonpb "github.com/Layr-Labs/eigenda/api/grpc/common"
+	"github.com/Layr-Labs/eigenda/core/auth"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPaymentSigner(t *testing.T) {
+	privateKey, err := crypto.GenerateKey()
+	require.NoError(t, err)
+
+	privateKeyHex := hex.EncodeToString(crypto.FromECDSA(privateKey))
+	signer := auth.NewPaymentSigner(privateKeyHex)
+
+	t.Run("SignBlobPayment", func(t *testing.T) {
+		header := &commonpb.PaymentHeader{
+			BinIndex:          1,
+			CumulativePayment: []byte{0x01, 0x02, 0x03},
+			AccountId:         "",
+		}
+
+		signature, err := signer.SignBlobPayment(header)
+		require.NoError(t, err)
+		assert.NotEmpty(t, signature)
+
+		// Verify the signature
+		isValid := auth.VerifyPaymentSignature(header, signature)
+		assert.True(t, isValid)
+	})
+
+	t.Run("VerifyPaymentSignature_InvalidSignature", func(t *testing.T) {
+		header := &commonpb.PaymentHeader{
+			BinIndex:          1,
+			CumulativePayment: []byte{0x01, 0x02, 0x03},
+			AccountId:         "",
+		}
+
+		// Create an invalid signature
+		invalidSignature := make([]byte, 65)
+		isValid := auth.VerifyPaymentSignature(header, invalidSignature)
+		assert.False(t, isValid)
+	})
+
+	t.Run("VerifyPaymentSignature_ModifiedHeader", func(t *testing.T) {
+		header := &commonpb.PaymentHeader{
+			BinIndex:          1,
+			CumulativePayment: []byte{0x01, 0x02, 0x03},
+			AccountId:         "",
+		}
+
+		signature, err := signer.SignBlobPayment(header)
+		require.NoError(t, err)
+
+		// Modify the header after signing
+		header.BinIndex = 2
+
+		isValid := auth.VerifyPaymentSignature(header, signature)
+		assert.False(t, isValid)
+	})
+}
+
+func TestNoopPaymentSigner(t *testing.T) {
+	signer := auth.NewNoopPaymentSigner()
+
+	t.Run("SignBlobRequest", func(t *testing.T) {
+		_, err := signer.SignBlobPayment(nil)
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "noop signer cannot sign blob payment header")
+	})
+}

core/data.go

@@ -7,6 +7,7 @@ import (
 	"math/big"
 	"strconv"
 
+	commonpb "github.com/Layr-Labs/eigenda/api/grpc/common"
 	"github.com/Layr-Labs/eigenda/common"
 	"github.com/Layr-Labs/eigenda/encoding"
 	"github.com/aws/aws-sdk-go-v2/service/dynamodb/types"
@@ -562,6 +563,15 @@ func (pm *PaymentMetadata) UnmarshalDynamoDBAttributeValue(av types.AttributeVal
 	return nil
 }
 
+// ConvertPaymentHeader converts a protobuf payment header to a PaymentMetadata
+func ConvertPaymentHeader(header *commonpb.PaymentHeader) *PaymentMetadata {
+	return &PaymentMetadata{
+		AccountID:         header.AccountId,
+		BinIndex:          header.BinIndex,
+		CumulativePayment: new(big.Int).SetBytes(header.CumulativePayment),
+	}
+}
+
 // OperatorInfo contains information about an operator which is stored on the blockchain state,
 // corresponding to a particular quorum
 type ActiveReservation struct {

core/eth/reader.go

@@ -599,3 +599,23 @@ func (t *Reader) GetOnDemandPaymentByAccount(ctx context.Context, blockNumber ui
 	// contract is not implemented yet
 	return core.OnDemandPayment{}, nil
 }
+
+func (t *Reader) GetGlobalSymbolsPerSecond(ctx context.Context) (uint64, error) {
+	// contract is not implemented yet
+	return 0, nil
+}
+
+func (t *Reader) GetMinNumSymbols(ctx context.Context) (uint32, error) {
+	// contract is not implemented yet
+	return 0, nil
+}
+
+func (t *Reader) GetPricePerSymbol(ctx context.Context) (uint32, error) {
+	// contract is not implemented yet
+	return 0, nil
+}
+
+func (t *Reader) GetReservationWindow(ctx context.Context) (uint32, error) {
+	// contract is not implemented yet
+	return 0, nil
+}