1 files changed, 159 insertions, 0 deletions
diff --git a/cmd/ethkey/message.go b/cmd/ethkey/message.go
new file mode 100644
index 000000000..531a931c8
--- /dev/null
+++ b/cmd/ethkey/message.go
@@ -0,0 +1,159 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"io/ioutil"
+
+	"github.com/ethereum/go-ethereum/accounts/keystore"
+	"github.com/ethereum/go-ethereum/cmd/utils"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"gopkg.in/urfave/cli.v1"
+)
+
+type outputSign struct {
+	Signature string
+}
+
+var msgfileFlag = cli.StringFlag{
+	Name:  "msgfile",
+	Usage: "file containing the message to sign/verify",
+}
+
+var commandSignMessage = cli.Command{
+	Name:      "signmessage",
+	Usage:     "sign a message",
+	ArgsUsage: "<keyfile> <message>",
+	Description: `
+Sign the message with a keyfile.
+
+To sign a message contained in a file, use the --msgfile flag.
+`,
+	Flags: []cli.Flag{
+		passphraseFlag,
+		jsonFlag,
+		msgfileFlag,
+	},
+	Action: func(ctx *cli.Context) error {
+		message := getMessage(ctx, 1)
+
+		// Load the keyfile.
+		keyfilepath := ctx.Args().First()
+		keyjson, err := ioutil.ReadFile(keyfilepath)
+		if err != nil {
+			utils.Fatalf("Failed to read the keyfile at '%s': %v", keyfilepath, err)
+		}
+
+		// Decrypt key with passphrase.
+		passphrase := getPassPhrase(ctx, false)
+		key, err := keystore.DecryptKey(keyjson, passphrase)
+		if err != nil {
+			utils.Fatalf("Error decrypting key: %v", err)
+		}
+
+		signature, err := crypto.Sign(signHash(message), key.PrivateKey)
+		if err != nil {
+			utils.Fatalf("Failed to sign message: %v", err)
+		}
+		out := outputSign{Signature: hex.EncodeToString(signature)}
+		if ctx.Bool(jsonFlag.Name) {
+			mustPrintJSON(out)
+		} else {
+			fmt.Println("Signature:", out.Signature)
+		}
+		return nil
+	},
+}
+
+type outputVerify struct {
+	Success            bool
+	RecoveredAddress   string
+	RecoveredPublicKey string
+}
+
+var commandVerifyMessage = cli.Command{
+	Name:      "verifymessage",
+	Usage:     "verify the signature of a signed message",
+	ArgsUsage: "<address> <signature> <message>",
+	Description: `
+Verify the signature of the message.
+It is possible to refer to a file containing the message.`,
+	Flags: []cli.Flag{
+		jsonFlag,
+		msgfileFlag,
+	},
+	Action: func(ctx *cli.Context) error {
+		addressStr := ctx.Args().First()
+		signatureHex := ctx.Args().Get(1)
+		message := getMessage(ctx, 2)
+
+		if !common.IsHexAddress(addressStr) {
+			utils.Fatalf("Invalid address: %s", addressStr)
+		}
+		address := common.HexToAddress(addressStr)
+		signature, err := hex.DecodeString(signatureHex)
+		if err != nil {
+			utils.Fatalf("Signature encoding is not hexadecimal: %v", err)
+		}
+
+		recoveredPubkey, err := crypto.SigToPub(signHash(message), signature)
+		if err != nil || recoveredPubkey == nil {
+			utils.Fatalf("Signature verification failed: %v", err)
+		}
+		recoveredPubkeyBytes := crypto.FromECDSAPub(recoveredPubkey)
+		recoveredAddress := crypto.PubkeyToAddress(*recoveredPubkey)
+		success := address == recoveredAddress
+
+		out := outputVerify{
+			Success:            success,
+			RecoveredPublicKey: hex.EncodeToString(recoveredPubkeyBytes),
+			RecoveredAddress:   recoveredAddress.Hex(),
+		}
+		if ctx.Bool(jsonFlag.Name) {
+			mustPrintJSON(out)
+		} else {
+			if out.Success {
+				fmt.Println("Signature verification successful!")
+			} else {
+				fmt.Println("Signature verification failed!")
+			}
+			fmt.Println("Recovered public key:", out.RecoveredPublicKey)
+			fmt.Println("Recovered address:", out.RecoveredAddress)
+		}
+		return nil
+	},
+}
+
+func getMessage(ctx *cli.Context, msgarg int) []byte {
+	if file := ctx.String("msgfile"); file != "" {
+		if len(ctx.Args()) > msgarg {
+			utils.Fatalf("Can't use --msgfile and message argument at the same time.")
+		}
+		msg, err := ioutil.ReadFile(file)
+		if err != nil {
+			utils.Fatalf("Can't read message file: %v", err)
+		}
+		return msg
+	} else if len(ctx.Args()) == msgarg+1 {
+		return []byte(ctx.Args().Get(msgarg))
+	}
+	utils.Fatalf("Invalid number of arguments: want %d, got %d", msgarg+1, len(ctx.Args()))
+	return nil
+}