auth.go

package core

import (
	"bytes"
	"errors"
	"fmt"

	geth "github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/crypto"
)

type BlobRequestAuthenticator interface {
	AuthenticateBlobRequest(header BlobAuthHeader) error
}

type BlobRequestSigner interface {
	SignBlobRequest(header BlobAuthHeader) ([]byte, error)
	GetAccountID() (string, error)
}

func VerifySignature(message []byte, accountAddr geth.Address, sig []byte) error {
	// Ensure the signature is 65 bytes (Recovery ID is the last byte)
	if len(sig) != 65 {
		return fmt.Errorf("signature length is unexpected: %d", len(sig))
	}

	publicKeyBytes, err := hexutil.Decode(accountAddr.Hex())
	if err != nil {
		return fmt.Errorf("failed to decode public key (%v): %v", accountAddr.Hex(), err)
	}

	// Decode public key
	pubKey, err := crypto.UnmarshalPubkey(publicKeyBytes)
	if err != nil {
		return fmt.Errorf("failed to decode public key (%v): %v", accountAddr.Hex(), err)
	}

	// Verify the signature
	sigPublicKeyECDSA, err := crypto.SigToPub(message, sig)
	if err != nil {
		return fmt.Errorf("failed to recover public key from signature: %v", err)
	}

	if !bytes.Equal(pubKey.X.Bytes(), sigPublicKeyECDSA.X.Bytes()) || !bytes.Equal(pubKey.Y.Bytes(), sigPublicKeyECDSA.Y.Bytes()) {
		return errors.New("signature doesn't match with provided public key")
	}

	return nil
}

type PaymentSigner interface {
	SignBlobPayment(header *PaymentMetadata) ([]byte, error)
	GetAccountID() string
}