import/export accounts

- cli: add passwordfile flag
- cli: change unlock flag only takes account
- cli: with unlock you are prompted for password or use passfile with password flag
- cli: unlockAccount used in normal client start (run) and accountExport
- cli: getPassword used in accountCreate and accountImport
- accounts: Manager.Import, Manager.Export
- crypto: SaveECDSA (to complement LoadECDSA) to save to file
- crypto: NewKeyFromECDSA added (used in accountImport and New = generated constructor)

accounts/account_manager.go

@@ -208,3 +208,23 @@ func zeroKey(k *ecdsa.PrivateKey) {
 		b[i] = 0
 	}
 }
+
+func (am *Manager) Export(path string, addr []byte, keyAuth string) error {
+	key, err := am.keyStore.GetKey(addr, keyAuth)
+	if err != nil {
+		return err
+	}
+	return crypto.SaveECDSA(path, key.PrivateKey)
+}
+
+func (am *Manager) Import(path string, keyAuth string) (Account, error) {
+	privateKeyECDSA, err := crypto.LoadECDSA(path)
+	if err != nil {
+		return Account{}, err
+	}
+	key := crypto.NewKeyFromECDSA(privateKeyECDSA)
+	if err = am.keyStore.StoreKey(key, keyAuth); err != nil {
+		return Account{}, err
+	}
+	return Account{Address: key.Address}, nil
+}