trezor-agent/libagent/device/fake_device.py
2018-01-05 20:53:42 +02:00

75 lines
2.5 KiB
Python

"""Fake device - ONLY FOR TESTS!!! (NEVER USE WITH REAL DATA)."""
import hashlib
import logging
import ecdsa
from . import interface
from .. import formats
log = logging.getLogger(__name__)
def _verify_support(identity):
"""Make sure the device supports given configuration."""
if identity.curve_name not in {formats.CURVE_NIST256}:
raise NotImplementedError(
'Unsupported elliptic curve: {}'.format(identity.curve_name))
class FakeDevice(interface.Device):
"""Connection to TREZOR device."""
@classmethod
def package_name(cls):
"""Python package name."""
return 'fake-device-agent'
def connect(self):
"""Return "dummy" connection."""
log.critical('NEVER USE THIS CODE FOR REAL-LIFE USE-CASES!!!')
log.critical('ONLY FOR DEBUGGING AND TESTING!!!')
# The code below uses HARD-CODED secret key - and should be used ONLY
# for GnuPG integration tests (e.g. when no real device is available).
# pylint: disable=attribute-defined-outside-init
self.secexp = 1
self.sk = ecdsa.SigningKey.from_secret_exponent(
secexp=self.secexp, curve=ecdsa.curves.NIST256p, hashfunc=hashlib.sha256)
self.vk = self.sk.get_verifying_key()
return self
def close(self):
"""Close connection."""
self.conn = None
def pubkey(self, identity, ecdh=False):
"""Return public key."""
_verify_support(identity)
data = self.vk.to_string()
x, y = data[:32], data[32:]
prefix = bytearray([2 + (bytearray(y)[0] & 1)])
return bytes(prefix) + x
def sign(self, identity, blob):
"""Sign given blob and return the signature (as bytes)."""
if identity.identity_dict['proto'] in {'ssh'}:
digest = hashlib.sha256(blob).digest()
else:
digest = blob
return self.sk.sign_digest_deterministic(digest=digest,
hashfunc=hashlib.sha256)
def ecdh(self, identity, pubkey):
"""Get shared session key using Elliptic Curve Diffie-Hellman."""
assert pubkey[:1] == b'\x04'
peer = ecdsa.VerifyingKey.from_string(
pubkey[1:],
curve=ecdsa.curves.NIST256p,
hashfunc=hashlib.sha256)
shared = ecdsa.VerifyingKey.from_public_point(
point=(peer.pubkey.point * self.secexp),
curve=ecdsa.curves.NIST256p,
hashfunc=hashlib.sha256)
return shared.to_string()