# ----------------------------------------------------------------------------------
# Electrum plugin for the Digital Bitbox hardware wallet by Shift Devices AG
# digitalbitbox.com
#
try:
import electrum
from electrum.bitcoin import TYPE_ADDRESS, var_int, msg_magic, Hash, verify_message, pubkey_from_signature, point_to_ser, public_key_to_p2pkh, EncodeAES, DecodeAES, MyVerifyingKey
from electrum.i18n import _
from electrum.keystore import Hardware_KeyStore
from ..hw_wallet import HW_PluginBase
from electrum.util import print_error
import time
import hid
import json
import math
import struct
import hashlib
from ecdsa.ecdsa import generator_secp256k1
from ecdsa.util import sigencode_der
from ecdsa.curves import SECP256k1
DIGIBOX = True
except ImportError as e:
DIGIBOX = False
# ----------------------------------------------------------------------------------
# USB HID interface
#
class DigitalBitbox_Client():
def __init__(self, hidDevice):
self.dbb_hid = hidDevice
self.opened = True
self.password = None
self.isInitialized = False
self.setupRunning = False
self.usbReportSize = 64 # firmware > v2.0.0
def close(self):
if self.opened:
try:
self.dbb_hid.close()
except:
pass
self.opened = False
def timeout(self, cutoff):
pass
def label(self):
return " "
def is_pairable(self):
return True
def is_initialized(self):
return self.dbb_has_password()
def is_paired(self):
return self.password is not None
def get_xpub(self, bip32_path):
if self.check_device_dialog():
msg = '{"xpub":"' + bip32_path + '"}'
reply = self.hid_send_encrypt(msg)
return reply['xpub']
return None
def dbb_has_password(self):
reply = self.hid_send_plain('{"ping":""}')
if 'ping' not in reply:
raise Exception('Device communication error. Please unplug and replug your Digital Bitbox.')
if reply['ping'] == 'password':
return True
return False
def stretch_key(self, key):
import pbkdf2, hmac
return pbkdf2.PBKDF2(key, 'Digital Bitbox', iterations = 20480, macmodule = hmac, digestmodule = hashlib.sha512).read(64).encode('hex')
def backup_password_dialog(self):
msg = _("Enter the password used when the backup was created:")
while True:
password = self.handler.get_passphrase(msg, False)
if password is None:
return None
if len(password) < 4:
msg = _("Password must have at least 4 characters.\r\n\r\nEnter password:")
elif len(password) > 64:
msg = _("Password must have less than 64 characters.\r\n\r\nEnter password:")
else:
return str(password)
def password_dialog(self, msg):
while True:
password = self.handler.get_passphrase(msg, False)
if password is None:
return False
if len(password) < 4:
msg = _("Password must have at least 4 characters.\r\n\r\nEnter password:")
elif len(password) > 64:
msg = _("Password must have less than 64 characters.\r\n\r\nEnter password:")
else:
self.password = str(password)
return True
def check_device_dialog(self):
# Set password if fresh device
if self.password is None and not self.dbb_has_password():
if not self.setupRunning:
return False # A fresh device cannot connect to an existing wallet
msg = _("An uninitialized Digital Bitbox is detected. " \
"Enter a new password below.\r\n\r\n REMEMBER THE PASSWORD!\r\n\r\n" \
"You cannot access your coins or a backup without the password.\r\n" \
"A backup is saved automatically when generating a new wallet.")
if self.password_dialog(msg):
reply = self.hid_send_plain('{"password":"' + self.password + '"}')
else:
return False
# Get password from user if not yet set
msg = _("Enter your Digital Bitbox password:")
while self.password is None:
if not self.password_dialog(msg):
return False
reply = self.hid_send_encrypt('{"led":"blink"}')
if 'error' in reply:
self.password = None
if reply['error']['code'] == 109:
msg = _("Incorrect password entered.\r\n\r\n" \
+ reply['error']['message'] + "\r\n\r\n" \
"Enter your Digital Bitbox password:")
else:
# Should never occur
msg = _("Unexpected error occurred.\r\n\r\n" \
+ reply['error']['message'] + "\r\n\r\n" \
"Enter your Digital Bitbox password:")
# Initialize device if not yet initialized
if not self.setupRunning:
self.isInitialized = True # Wallet exists. Electrum code later checks if the device matches the wallet
elif not self.isInitialized:
reply = self.hid_send_encrypt('{"device":"info"}')
if reply['device']['id'] <> "":
self.recover_or_erase_dialog() # Already seeded
else:
self.seed_device_dialog() # Seed if not initialized
return self.isInitialized
def recover_or_erase_dialog(self):
msg = _("The Digital Bitbox is already seeded. Choose an option:\n")
choices = [
(_("Create a wallet using the current seed")),
(_("Load a wallet from the micro SD card (the current seed is overwritten)")),
(_("Erase the Digital Bitbox"))
]
try:
reply = self.handler.win.query_choice(msg, choices)
except Exception:
return # Back button pushed
if reply == 2:
self.dbb_erase()
elif reply == 1:
if not self.dbb_load_backup():
return
else:
pass # Use existing seed
self.isInitialized = True
def seed_device_dialog(self):
msg = _("Choose how to initialize your Digital Bitbox:\n")
choices = [
(_("Generate a new random wallet")),
(_("Load a wallet from the micro SD card"))
]
try:
reply = self.handler.win.query_choice(msg, choices)
except Exception:
return # Back button pushed
if reply == 0:
self.dbb_generate_wallet()
else:
if not self.dbb_load_backup(show_msg=False):
return
self.isInitialized = True
def dbb_generate_wallet(self):
key = self.stretch_key(self.password)
filename = "Electrum-" + time.strftime("%Y-%m-%d-%H-%M-%S") + ".pdf"
msg = '{"seed":{"source": "create", "key": "%s", "filename": "%s", "entropy": "%s"}}' % (key, filename, 'Digital Bitbox Electrum Plugin')
reply = self.hid_send_encrypt(msg)
if 'error' in reply:
raise Exception(reply['error']['message'])
def dbb_erase(self):
self.handler.show_message(_("Are you sure you want to erase the Digital Bitbox?\r\n\r\n" \
"To continue, touch the Digital Bitbox's light for 3 seconds.\r\n\r\n" \
"To cancel, briefly touch the light or wait for the timeout."))
hid_reply = self.hid_send_encrypt('{"reset":"__ERASE__"}')
self.handler.clear_dialog()
if 'error' in hid_reply:
raise Exception(hid_reply['error']['message'])
else:
self.password = None
raise Exception('Device erased')
def dbb_load_backup(self, show_msg=True):
backups = self.hid_send_encrypt('{"backup":"list"}')
if 'error' in backups:
raise Exception(backups['error']['message'])
try:
f = self.handler.win.query_choice(_("Choose a backup file:"), backups['backup'])
except Exception:
return False # Back button pushed
key = self.backup_password_dialog()
if key is None:
raise Exception('Canceled by user')
key = self.stretch_key(key)
if show_msg:
self.handler.show_message(_("Loading backup...\r\n\r\n" \
"To continue, touch the Digital Bitbox's light for 3 seconds.\r\n\r\n" \
"To cancel, briefly touch the light or wait for the timeout."))
msg = '{"seed":{"source": "backup", "key": "%s", "filename": "%s"}}' % (key, backups['backup'][f])
hid_reply = self.hid_send_encrypt(msg)
self.handler.clear_dialog()
if 'error' in hid_reply:
raise Exception(hid_reply['error']['message'])
return True
def hid_send_frame(self, data):
HWW_CID = 0xFF000000
HWW_CMD = 0x80 + 0x40 + 0x01
data = bytearray(data)
data_len = len(data)
seq = 0;
idx = 0;
write = []
while idx < data_len:
if idx == 0:
# INIT frame
write = data[idx : idx + min(data_len, self.usbReportSize - 7)]
self.dbb_hid.write('\0' + struct.pack(">IBH", HWW_CID, HWW_CMD, data_len & 0xFFFF) + write + '\xEE' * (self.usbReportSize - 7 - len(write)))
else:
# CONT frame
write = data[idx : idx + min(data_len, self.usbReportSize - 5)]
self.dbb_hid.write('\0' + struct.pack(">IB", HWW_CID, seq) + write + '\xEE' * (self.usbReportSize - 5 - len(write)))
seq += 1
idx += len(write)
def hid_read_frame(self):
# INIT response
read = self.dbb_hid.read(self.usbReportSize)
cid = ((read[0] * 256 + read[1]) * 256 + read[2]) * 256 + read[3]
cmd = read[4]
data_len = read[5] * 256 + read[6]
data = read[7:]
idx = len(read) - 7;
while idx < data_len:
# CONT response
read = self.dbb_hid.read(self.usbReportSize)
data += read[5:]
idx += len(read) - 5
return data
def hid_send_plain(self, msg):
reply = ""
try:
serial_number = self.dbb_hid.get_serial_number_string()
if "v2.0." in serial_number or "v1." in serial_number:
hidBufSize = 4096
self.dbb_hid.write('\0' + bytearray(msg) + '\0' * (hidBufSize - len(msg)))
r = []
while len(r) < hidBufSize:
r = r + self.dbb_hid.read(hidBufSize)
else:
self.hid_send_frame(msg)
r = self.hid_read_frame()
r = str(bytearray(r)).rstrip(' \t\r\n\0')
r = r.replace("\0", '')
reply = json.loads(r)
except Exception as e:
print_error('Exception caught ' + str(e))
return reply
def hid_send_encrypt(self, msg):
reply = ""
try:
secret = Hash(self.password)
msg = EncodeAES(secret, msg)
reply = self.hid_send_plain(msg)
if 'ciphertext' in reply:
reply = DecodeAES(secret, ''.join(reply["ciphertext"]))
reply = json.loads(reply)
if 'error' in reply:
self.password = None
except Exception as e:
print_error('Exception caught ' + str(e))
return reply
# ----------------------------------------------------------------------------------
#
#
class DigitalBitbox_KeyStore(Hardware_KeyStore):
hw_type = 'digitalbitbox'
device = 'DigitalBitbox'
def __init__(self, d):
Hardware_KeyStore.__init__(self, d)
self.force_watching_only = False
self.maxInputs = 14 # maximum inputs per single sign command
def get_derivation(self):
return str(self.derivation)
def give_error(self, message, clear_client = False):
if clear_client:
self.client = None
raise Exception(message)
def decrypt_message(self, pubkey, message, password):
raise RuntimeError(_('Encryption and decryption are currently not supported for %s') % self.device)
def sign_message(self, sequence, message, password):
sig = None
try:
inputPath = self.get_derivation() + "/%d/%d" % sequence
inputHash = Hash(msg_magic(message)).encode('hex')
hasharray = []
hasharray.append({'hash': inputHash, 'keypath': inputPath})
hasharray = json.dumps(hasharray)
msg = '{"sign":{"meta":"sign message", "data":%s}}' % (hasharray)
dbb_client = self.plugin.get_client(self)
if not dbb_client.is_paired():
raise Exception("Could not sign message.")
reply = dbb_client.hid_send_encrypt(msg)
self.handler.show_message(_("Signing message ...\r\n\r\n" \
"To continue, touch the Digital Bitbox's blinking light for 3 seconds.\r\n\r\n" \
"To cancel, briefly touch the blinking light or wait for the timeout."))
reply = dbb_client.hid_send_encrypt(msg) # Send twice, first returns an echo for smart verification (not implemented)
self.handler.clear_dialog()
if 'error' in reply:
raise Exception(reply['error']['message'])
if 'sign' not in reply:
raise Exception("Could not sign message.")
if 'recid' in reply['sign'][0]:
# firmware > v2.1.1
sig = chr(27 + int(reply['sign'][0]['recid'], 16) + 4) + reply['sign'][0]['sig'].decode('hex')
h = Hash(msg_magic(message))
pk, compressed = pubkey_from_signature(sig, h)
pk = point_to_ser(pk.pubkey.point, compressed)
addr = public_key_to_p2pkh(pk)
if verify_message(addr, sig, message) is False:
raise Exception("Could not sign message")
elif 'pubkey' in reply['sign'][0]:
# firmware <= v2.1.1
for i in range(4):
sig = chr(27 + i + 4) + reply['sign'][0]['sig'].decode('hex')
try:
addr = public_key_to_p2pkh(reply['sign'][0]['pubkey'].decode('hex'))
if verify_message(addr, sig, message):
break
except Exception:
continue
else:
raise Exception("Could not sign message")
except BaseException as e:
self.give_error(e)
return sig
def sign_transaction(self, tx, password):
if tx.is_complete():
return
try:
p2shTransaction = False
derivations = self.get_tx_derivations(tx)
inputhasharray = []
hasharray = []
pubkeyarray = []
# Build hasharray from inputs
for i, txin in enumerate(tx.inputs()):
if txin['type'] == 'coinbase':
self.give_error("Coinbase not supported") # should never happen
if txin['type'] in ['p2sh']:
p2shTransaction = True
for x_pubkey in txin['x_pubkeys']:
if x_pubkey in derivations:
index = derivations.get(x_pubkey)
inputPath = "%s/%d/%d" % (self.get_derivation(), index[0], index[1])
inputHash = Hash(tx.serialize_preimage(i).decode('hex'))
hasharray_i = {'hash': inputHash.encode('hex'), 'keypath': inputPath}
hasharray.append(hasharray_i)
inputhasharray.append(inputHash)
break
else:
self.give_error("No matching x_key for sign_transaction") # should never happen
# Sanity check
if p2shTransaction:
for txinput in tx.inputs():
if txinput['type'] != 'p2sh':
self.give_error("P2SH / regular input mixed in same transaction not supported") # should never happen
# Build pubkeyarray from outputs (unused because echo for smart verification not implemented)
if not p2shTransaction:
for _type, address, amount in tx.outputs():
assert _type == TYPE_ADDRESS
info = tx.output_info.get(address)
if info is not None:
index, xpubs, m = info
changePath = self.get_derivation() + "/%d/%d" % index
changePubkey = self.derive_pubkey(index[0], index[1])
pubkeyarray_i = {'pubkey': changePubkey, 'keypath': changePath}
pubkeyarray.append(pubkeyarray_i)
# Build sign command
dbb_signatures = []
steps = math.ceil(1.0 * len(hasharray) / self.maxInputs)
for step in range(int(steps)):
hashes = hasharray[step * self.maxInputs : (step + 1) * self.maxInputs]
msg = '{"sign": {"meta":"%s", "data":%s, "checkpub":%s} }' % \
(Hash(tx.serialize()).encode('hex'), json.dumps(hashes), json.dumps(pubkeyarray))
dbb_client = self.plugin.get_client(self)
if not dbb_client.is_paired():
raise Exception("Could not sign transaction.")
reply = dbb_client.hid_send_encrypt(msg)
if 'error' in reply:
raise Exception(reply['error']['message'])
if 'echo' not in reply:
raise Exception("Could not sign transaction.")
if steps > 1:
self.handler.show_message(_("Signing large transaction. Please be patient ...\r\n\r\n" \
"To continue, touch the Digital Bitbox's blinking light for 3 seconds. " \
"(Touch " + str(step + 1) + " of " + str(int(steps)) + ")\r\n\r\n" \
"To cancel, briefly touch the blinking light or wait for the timeout.\r\n\r\n"))
else:
self.handler.show_message(_("Signing transaction ...\r\n\r\n" \
"To continue, touch the Digital Bitbox's blinking light for 3 seconds.\r\n\r\n" \
"To cancel, briefly touch the blinking light or wait for the timeout."))
reply = dbb_client.hid_send_encrypt(msg) # Send twice, first returns an echo for smart verification (not implemented)
self.handler.clear_dialog()
if 'error' in reply:
raise Exception(reply['error']['message'])
if 'sign' not in reply:
raise Exception("Could not sign transaction.")
dbb_signatures.extend(reply['sign'])
# Fill signatures
if len(dbb_signatures) <> len(tx.inputs()):
raise Exception("Incorrect number of transactions signed.") # Should never occur
for i, txin in enumerate(tx.inputs()):
num = txin['num_sig']
for pubkey in txin['pubkeys']:
signatures = filter(None, txin['signatures'])
if len(signatures) == num:
break # txin is complete
ii = txin['pubkeys'].index(pubkey)
signed = dbb_signatures[i]
if 'recid' in signed:
# firmware > v2.1.1
recid = int(signed['recid'], 16)
s = signed['sig'].decode('hex')
h = inputhasharray[i]
pk = MyVerifyingKey.from_signature(s, recid, h, curve = SECP256k1)
pk = point_to_ser(pk.pubkey.point, True).encode('hex')
elif 'pubkey' in signed:
# firmware <= v2.1.1
pk = signed['pubkey']
if pk != pubkey:
continue
sig_r = int(signed['sig'][:64], 16)
sig_s = int(signed['sig'][64:], 16)
sig = sigencode_der(sig_r, sig_s, generator_secp256k1.order())
txin['signatures'][ii] = sig.encode('hex') + '01'
tx._inputs[i] = txin
except BaseException as e:
self.give_error(e, True)
else:
print_error("Transaction is_complete", tx.is_complete())
tx.raw = tx.serialize()
class DigitalBitboxPlugin(HW_PluginBase):
libraries_available = DIGIBOX
keystore_class = DigitalBitbox_KeyStore
client = None
DEVICE_IDS = [
(0x03eb, 0x2402) # Digital Bitbox
]
def __init__(self, parent, config, name):
HW_PluginBase.__init__(self, parent, config, name)
if self.libraries_available:
self.device_manager().register_devices(self.DEVICE_IDS)
def get_dbb_device(self, device):
dev = hid.device()
dev.open_path(device.path)
return dev
def create_client(self, device, handler):
if device.interface_number == 0 or device.usage_page == 0xffff:
self.handler = handler
client = self.get_dbb_device(device)
if client <> None:
client = DigitalBitbox_Client(client)
return client
else:
return None
def setup_device(self, device_info, wizard):
devmgr = self.device_manager()
device_id = device_info.device.id_
client = devmgr.client_by_id(device_id)
client.handler = self.create_handler(wizard)
client.setupRunning = True
client.get_xpub("m/44'/0'")
def get_xpub(self, device_id, derivation, wizard):
devmgr = self.device_manager()
client = devmgr.client_by_id(device_id)
client.handler = self.create_handler(wizard)
client.check_device_dialog()
xpub = client.get_xpub(derivation)
return xpub
def get_client(self, keystore, force_pair=True):
devmgr = self.device_manager()
handler = keystore.handler
with devmgr.hid_lock:
client = devmgr.client_for_keystore(self, handler, keystore, force_pair)
if client <> None:
client.check_device_dialog()
return client