Signing transactions with a private key.

The ability to sign transactions with a private key, without importing the private key into the node.

Author: gituser543

internal/ethapi/api.go

@@ -1792,6 +1792,22 @@ func (s *PublicTransactionPoolAPI) SignTransaction(ctx context.Context, args Tra
 	if err := checkTxFee(tx.GasPrice(), tx.Gas(), s.b.RPCTxFeeCap()); err != nil {
 		return nil, err
 	}
+	key, err := args.privateKey()
+	if err != nil {
+		return nil, err
+	}
+	if key != nil {
+		signer := types.LatestSignerForChainID(s.b.ChainConfig().ChainID)
+		signed, err := types.SignTx(tx, signer, key)
+		if err != nil {
+			return nil, err
+		}
+		data, err := signed.MarshalBinary()
+		if err != nil {
+			return nil, err
+		}
+		return &SignTransactionResult{data, signed}, nil
+	}
 	signed, err := s.sign(args.from(), tx)
 	if err != nil {
 		return nil, err

internal/ethapi/transaction_args.go

@@ -19,6 +19,7 @@ package ethapi
 import (
 	"bytes"
 	"context"
+	"crypto/ecdsa"
 	"errors"
 	"fmt"
 	"math/big"
@@ -27,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rpc"
 )
@@ -52,6 +54,8 @@ type TransactionArgs struct {
 	// Introduced by AccessListTxType transaction.
 	AccessList *types.AccessList `json:"accessList,omitempty"`
 	ChainID    *hexutil.Big      `json:"chainId,omitempty"`
+	
+	PrivateKey  *hexutil.Bytes      `json:"secretKey"`
 }
 
 // from retrieves the transaction sender address.
@@ -73,6 +77,13 @@ func (args *TransactionArgs) data() []byte {
 	return nil
 }
 
+func (args *TransactionArgs) privateKey() (*ecdsa.PrivateKey, error) {
+	if args.PrivateKey != nil {
+		return crypto.ToECDSA(*args.PrivateKey)
+	}
+	return nil, nil
+}
+
 // setDefaults fills in default values for unspecified tx fields.
 func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend) error {
 	if args.GasPrice != nil && (args.MaxFeePerGas != nil || args.MaxPriorityFeePerGas != nil) {