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First functional version

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This commit is contained in:
Pedro Ferreira
2017-06-04 21:50:49 +02:00
commit 66a4149f12
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24
secret_handshake/__init__.py Normal file
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# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
from .network import SHSClient, SHSServer
__all__ = ('SHSClient', 'SHSServer')

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secret_handshake/boxstream.py Normal file
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import struct
from nacl.secret import SecretBox
from .util import bytes_to_long, long_to_bytes
NONCE_SIZE = 24
HEADER_LENGTH = 2 + 16 + 16
MAX_SEGMENT_SIZE = 4 * 1024
TERMINATION_HEADER = (b'\x00' * 18)
MAX_NONCE = (8 * NONCE_SIZE)
# TODO: Implement handling of messages > 4k
def inc_nonce(nonce):
num = bytes_to_long(nonce) + 1
if num > 2 ** MAX_NONCE:
num = 0
bnum = long_to_bytes(num)
bnum = b'\x00' * (NONCE_SIZE - len(bnum)) + bnum
return bnum
def get_stream_pair(reader, writer, **kwargs):
"""Return a tuple with `(unbox_stream, box_stream)` (reader/writer).
:return: (:class:`secret_handshake.boxstream.UnboxStream`,
:class:`secret_handshake.boxstream.BoxStream`) """
box_args = {
'key': kwargs['encrypt_key'],
'nonce': kwargs['encrypt_nonce'],
}
unbox_args = {
'key': kwargs['decrypt_key'],
'nonce': kwargs['decrypt_nonce'],
}
return UnboxStream(reader, **unbox_args), BoxStream(writer, **box_args)
class UnboxStream(object):
def __init__(self, reader, key, nonce):
self.reader = reader
self.key = key
self.nonce = nonce
self.closed = False
async def read(self):
data = await self.reader.read(HEADER_LENGTH)
if not data:
self.closed = True
return None
box = SecretBox(self.key)
header = box.decrypt(data, self.nonce)
if header == TERMINATION_HEADER:
self.closed = True
return None
length = struct.unpack('>H', header[:2])[0]
mac = header[2:]
data = await self.reader.read(length)
body = box.decrypt(mac + data, inc_nonce(self.nonce))
self.nonce = inc_nonce(inc_nonce(self.nonce))
return body
async def __aiter__(self):
while True:
data = await self.read()
if data is None:
return
yield data
class BoxStream(object):
def __init__(self, writer, key, nonce):
self.writer = writer
self.key = key
self.box = SecretBox(self.key)
self.nonce = nonce
def write(self, data):
# XXX: This nonce logic is almost for sure wrong
body = self.box.encrypt(data, inc_nonce(self.nonce))[24:]
header = struct.pack('>H', len(body) - 16) + body[:16]
hdrbox = self.box.encrypt(header, self.nonce)[24:]
self.writer.write(hdrbox)
self.nonce = inc_nonce(inc_nonce(self.nonce))
self.writer.write(body[16:])
def close(self):
self.writer.write(self.box.encrypt(b'\x00' * 18, self.nonce)[24:])

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secret_handshake/crypto.py Normal file
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# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import hashlib
import hmac
from base64 import b64decode
from nacl.bindings import crypto_scalarmult, crypto_box_afternm, crypto_box_open_afternm
from nacl.exceptions import CryptoError
from nacl.public import PrivateKey
from nacl.signing import VerifyKey
APPLICATION_KEY = b64decode('1KHLiKZvAvjbY1ziZEHMXawbCEIM6qwjCDm3VYRan/s=')
class SHSError(Exception):
"""A SHS exception."""
pass
class SHSCryptoBase(object):
def __init__(self, local_key, ephemeral_key=None, application_key=None):
self.local_key = local_key
self.application_key = application_key or APPLICATION_KEY
self._reset_keys(ephemeral_key or PrivateKey.generate())
def _reset_keys(self, ephemeral_key):
self.local_ephemeral_key = ephemeral_key
self.local_app_hmac = (hmac.new(self.application_key, bytes(ephemeral_key.public_key), digestmod='sha512')
.digest()[:32])
def generate_challenge(self):
"""Generate and return a challenge to be sent to the server."""
return self.local_app_hmac + bytes(self.local_ephemeral_key.public_key)
def verify_challenge(self, data):
"""Verify the correctness of challenge sent from the client."""
assert len(data) == 64
sent_hmac, remote_ephemeral_key = data[:32], data[32:]
h = hmac.new(self.application_key, remote_ephemeral_key, digestmod='sha512')
self.remote_app_hmac = h.digest()[:32]
ok = self.remote_app_hmac == sent_hmac
if ok:
# this is (a * b)
self.shared_secret = crypto_scalarmult(bytes(self.local_ephemeral_key), remote_ephemeral_key)
self.remote_ephemeral_key = remote_ephemeral_key
# this is hash(a * b)
self.shared_hash = hashlib.sha256(self.shared_secret).digest()
return ok
def clean(self, new_ephemeral_key=None):
self._reset_keys(new_ephemeral_key or PrivateKey.generate())
self.shared_secret = None
self.shared_hash = None
self.remote_ephemeral_key = None
def get_box_keys(self):
shared_secret = hashlib.sha256(self.box_secret).digest()
return {
'shared_secret': shared_secret,
'encrypt_key': hashlib.sha256(shared_secret + bytes(self.remote_pub_key)).digest(),
'decrypt_key': hashlib.sha256(shared_secret + bytes(self.local_key.verify_key)).digest(),
'encrypt_nonce': self.remote_app_hmac[:24],
'decrypt_nonce': self.local_app_hmac[:24]
}
class SHSServerCrypto(SHSCryptoBase):
def verify_client_auth(self, data):
assert len(data) == 112
a_bob = crypto_scalarmult(bytes(self.local_key.to_curve25519_private_key()), self.remote_ephemeral_key)
box_secret = hashlib.sha256(self.application_key + self.shared_secret + a_bob).digest()
self.hello = crypto_box_open_afternm(data, b'\x00' * 24, box_secret)
signature, public_key = self.hello[:64], self.hello[64:]
signed = self.application_key + bytes(self.local_key.verify_key) + self.shared_hash
pkey = VerifyKey(public_key)
# will raise an exception if verification fails
pkey.verify(signed, signature)
self.remote_pub_key = pkey
b_alice = crypto_scalarmult(bytes(self.local_ephemeral_key),
bytes(self.remote_pub_key.to_curve25519_public_key()))
self.box_secret = hashlib.sha256(self.application_key + self.shared_secret + a_bob + b_alice).digest()[:32]
return True
def generate_accept(self):
okay = self.local_key.sign(self.application_key + self.hello + self.shared_hash).signature
d = crypto_box_afternm(okay, b'\x00' * 24, self.box_secret)
return d
def clean(self, new_ephemeral_key=None):
super(SHSServerCrypto, self).clean(new_ephemeral_key=new_ephemeral_key)
self.hello = None
self.local_lterm_shared = None
class SHSClientCrypto(SHSCryptoBase):
"""An object that encapsulates all the SHS client-side crypto.
:param local_key: the keypair used by the client (:class:`nacl.public.PrivateKey` object)
:param server_pub_key: the server's public key (``byte`` string)
:param ephemeral_key: a fresh local :class:`nacl.public.PrivateKey`
:param application_key: the unique application key (``byte`` string), defaults to SSB's
"""
def __init__(self, local_key, server_pub_key, ephemeral_key, application_key=None):
super(SHSClientCrypto, self).__init__(local_key, ephemeral_key, application_key)
self.remote_pub_key = VerifyKey(server_pub_key)
def verify_server_challenge(self, data):
"""Verify the correctness of challenge sent from the server."""
# TODO: use super.verify_challenge and add extra logic
return super(SHSClientCrypto, self).verify_challenge(data)
def generate_client_auth(self):
"""Generate box[K|a*b|a*B](H)"""
curve_pkey = self.remote_pub_key.to_curve25519_public_key()
# remote_lterm_shared is (a * B)
remote_lterm_shared = crypto_scalarmult(bytes(self.local_ephemeral_key), bytes(curve_pkey))
self.remote_lterm_shared = remote_lterm_shared
# this shall be hash(K | a * b | a * B)
box_secret = hashlib.sha256(self.application_key + self.shared_secret + remote_lterm_shared).digest()
# and message_to_box will correspond to H = sign(A)[K | Bp | hash(a * b)] | Ap
signed_message = self.local_key.sign(self.application_key + bytes(self.remote_pub_key) + self.shared_hash)
message_to_box = signed_message.signature + bytes(self.local_key.verify_key)
self.client_auth = message_to_box
nonce = b"\x00" * 24
# return box(K | a * b | a * B)[H]
return crypto_box_afternm(message_to_box, nonce, box_secret)
def verify_server_accept(self, data):
"""Verify that the server's accept message is sane"""
curve_lkey = self.local_key.to_curve25519_private_key()
# local_lterm_shared is (A * b)
local_lterm_shared = crypto_scalarmult(bytes(curve_lkey), self.remote_ephemeral_key)
self.local_lterm_shared = local_lterm_shared
# this is hash(K | a * b | a * B | A * b)
self.box_secret = hashlib.sha256(self.application_key + self.shared_secret + self.remote_lterm_shared +
local_lterm_shared).digest()
nonce = b"\x00" * 24
try:
# let's use the box secret to unbox our encrypted message
signature = crypto_box_open_afternm(data, nonce, self.box_secret)
except CryptoError:
raise SHSError('Error decrypting server acceptance message')
# we should have received sign(B)[K | H | hash(a * b)]
# let's see if that signature can verify the reconstructed data on our side
self.remote_pub_key.verify(self.application_key + self.client_auth + self.shared_hash, signature)
return True
def clean(self, new_ephemeral_key=None):
super(SHSClientCrypto, self).clean(new_ephemeral_key=new_ephemeral_key)
self.remote_lterm_shared = None
self.local_lterm_shared = None

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secret_handshake/network.py Normal file
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# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
from asyncio import open_connection, start_server
from .boxstream import get_stream_pair
from .crypto import SHSClientCrypto, SHSServerCrypto
class SHSClientException(Exception):
pass
class SHSSocket(object):
def __init__(self, loop):
self.loop = loop
def write(self, data):
self.write_stream.write(data)
async def read(self):
return await self.read_stream.read()
async def disconnect(self):
self.writer.close()
async def __aiter__(self):
async for msg in self.read_stream:
yield msg
class SHSServer(SHSSocket):
def __init__(self, host, port, server_kp, application_key=None, loop=None):
super(SHSServer, self).__init__(loop)
self.host = host
self.port = port
self.crypto = SHSServerCrypto(server_kp, application_key=application_key)
self._on_connect = None
async def _handshake(self, reader, writer):
data = await reader.read(64)
if not self.crypto.verify_challenge(data):
raise SHSClientException('Client challenge is not valid')
writer.write(self.crypto.generate_challenge())
data = await reader.read(112)
if not self.crypto.verify_client_auth(data):
raise SHSClientException('Client auth is not valid')
writer.write(self.crypto.generate_accept())
async def handle_connection(self, reader, writer):
self.crypto.clean()
await self._handshake(reader, writer)
keys = self.crypto.get_box_keys()
self.crypto.clean()
self.read_stream, self.write_stream = get_stream_pair(reader, writer, **keys)
self.writer = writer
if self._on_connect:
await self._on_connect()
def listen(self):
self.loop.run_until_complete(start_server(self.handle_connection, self.host, self.port, loop=self.loop))
def on_connect(self, cb):
self._on_connect = cb
class SHSClient(SHSSocket):
def __init__(self, host, port, client_kp, server_pub_key, ephemeral_key=None, application_key=None, loop=None):
super(SHSClient, self).__init__(loop)
self.host = host
self.port = port
self.crypto = SHSClientCrypto(client_kp, server_pub_key, ephemeral_key=ephemeral_key,
application_key=application_key)
async def _handshake(self, reader, writer):
writer.write(self.crypto.generate_challenge())
data = await reader.read(64)
if not self.crypto.verify_server_challenge(data):
raise SHSClientException('Server challenge is not valid')
writer.write(self.crypto.generate_client_auth())
data = await reader.read(80)
if not self.crypto.verify_server_accept(data):
raise SHSClientException('Server accept is not valid')
def connect(self):
reader, writer = self.loop.run_until_complete(open_connection(self.host, self.port, loop=self.loop))
self.loop.run_until_complete(self._handshake(reader, writer))
keys = self.crypto.get_box_keys()
self.crypto.clean()
self.read_stream, self.write_stream = get_stream_pair(reader, writer, **keys)
self.writer = writer

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secret_handshake/test_boxstream.py Normal file
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# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import pytest
from io import BytesIO
from .test_crypto import (CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
from secret_handshake.boxstream import BoxStream, UnboxStream
MESSAGE_1 = (b'\xcev\xedE\x06l\x02\x13\xc8\x17V\xfa\x8bZ?\x88B%O\xb0L\x9f\x8e\x8c0y\x1dv\xc0\xc9\xf6\x9d\xc2\xdf\xdb'
b'\xee\x9d')
MESSAGE_2 = b"\x141\xd63\x13d\xd1\xecZ\x9b\xd0\xd4\x03\xcdR?'\xaa.\x89I\x92I\xf9guL\xaa\x06?\xea\xca/}\x88*\xb2"
MESSAGE_3 = (b'\xcbYY\xf1\x0f\xa5O\x13r\xa6"\x15\xc5\x9d\r.*\x0b\x92\x10m\xa6(\x0c\x0c\xc61\x80j\x81)\x800\xed\xda'
b'\xad\xa1')
MESSAGE_CLOSED = b'\xb1\x14hU\'\xb5M\xa6"\x03\x9duy\xa1\xd4evW,\xdcE\x18\xe4+ C4\xe8h\x96\xed\xc5\x94\x80'
class AsyncBuffer(BytesIO):
"""Just a BytesIO with an async read method."""
async def read(self, n=None):
return super(AsyncBuffer, self).read(n)
@pytest.mark.asyncio
async def test_boxstream():
buffer = AsyncBuffer()
box_stream = BoxStream(buffer, CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
box_stream.write(b'foo')
buffer.seek(0)
assert await buffer.read() == MESSAGE_1
pos = buffer.tell()
box_stream.write(b'foo')
buffer.seek(pos)
assert await buffer.read() == MESSAGE_2
pos = buffer.tell()
box_stream.write(b'bar')
buffer.seek(pos)
assert await buffer.read() == MESSAGE_3
pos = buffer.tell()
box_stream.close()
buffer.seek(pos)
assert await buffer.read() == MESSAGE_CLOSED
@pytest.mark.asyncio
async def test_unboxstream():
buffer = AsyncBuffer(MESSAGE_1 + MESSAGE_2 + MESSAGE_3 + MESSAGE_CLOSED)
buffer.seek(0)
unbox_stream = UnboxStream(buffer, CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
assert not unbox_stream.closed
assert [msg async for msg in unbox_stream] == [b'foo', b'foo', b'bar']
assert unbox_stream.closed

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secret_handshake/test_crypto.py Normal file
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# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import hashlib
import pytest
from nacl.public import PrivateKey
from nacl.signing import SigningKey
from secret_handshake.crypto import SHSClientCrypto, SHSServerCrypto
APP_KEY = hashlib.sha256(b'app_key').digest()
SERVER_KEY_SEED = b'\xcaw\x01\xc2cQ\xfd\x94\x9f\x14\x84\x0c0<l\xd8\xe4\xf5>\x12\\\x96\xcd\x9b\x0c\x02z&\x96!\xe0\xa2'
CLIENT_KEY_SEED = b'\xbf\x02<\xd3e\x9d\xac-\xd1\x9e-{\xe5q\x90\x03\x11\xba\x8cSQ\xa0\xc3p~\x89\xe6\xeeb\xaa\x1c\x17'
SERVER_EPH_KEY_SEED = b"ed\x1c\x01\x03s\x04\xdc\x8e`\xd6Z\xd0u;\xcbX\x91\xd8ZO\xf8\xf0\xd6'\xd5\xb1Yy\x13yH"
CLIENT_EPH_KEY_SEED = b'u8\xd0\xe3\x85d_Pz\x0c\xf5\xfd\x15\xce2p#\xb0\xf0\x9f\xe6!\xe1\xcb\xf6\x93\t\xebr{1\x8b'
@pytest.fixture()
def server():
server_key = SigningKey(SERVER_KEY_SEED)
server_eph_key = PrivateKey(SERVER_EPH_KEY_SEED)
return SHSServerCrypto(server_key, server_eph_key, application_key=APP_KEY)
@pytest.fixture()
def client():
client_key = SigningKey(CLIENT_KEY_SEED)
server_key = SigningKey(SERVER_KEY_SEED)
client_eph_key = PrivateKey(CLIENT_EPH_KEY_SEED)
return SHSClientCrypto(client_key, bytes(server_key.verify_key), client_eph_key, application_key=APP_KEY)
CLIENT_CHALLENGE = (b'd\xe8\xccD\xec\xb9E\xbb\xaa\xa7\x7f\xe38\x15\x16\xef\xca\xd22u\x1d\xfe<\xe7j'
b'\xd7\xf0uc\xf0r\xf3\x7f\t\x18\xec\x8c\xf7\xff\x8e\xa9\xc83\x13\x18R\x16\x1d'
b'\xe5\xc6K\xae\x94\xdbVt\x84\xdc\x1c@+D\x1c%')
CLIENT_AUTH = (b'\xf2\xaf?z\x15\x10\xd0\xf0\xdf\xe3\x91\xfe\x14\x1c}z\xab\xeey\xf5\xef\xfc\xa1EdV\xf2T\x95s[!$z'
b'\xeb\x8f\x1b\x96JP\x17^\x92\xc8\x9e\xb4*5`\xf2\x8fI.\x93\xb9\x14:\xca@\x06\xff\xd1\xf1J\xc8t\xc4'
b'\xd8\xc3$[\xc5\x94je\x83\x00%\x99\x10\x16\xb1\xa2\xb2\xb7\xbf\xc9\x88\x14\xb9\xbb^\tzq\xa4\xef\xc5'
b'\xf5\x1f7#\xed\x92X\xb2\xe3\xe5\x8b[t3')
SERVER_CHALLENGE = (b'S\\\x06\x8d\xe5\xeb&*\xb8\x0bp\xb3Z\x8e\\\x85\x14\xaa\x1c\x8di\x9d\x7f\xa9\xeawl\xb9}\x85\xc3ik'
b'\x0c ($E\xb4\x8ax\xc4)t<\xd7\x8b\xd6\x07\xb7\xecw\x84\r\xe1-Iz`\xeb\x04\x89\xd6{')
SERVER_ACCEPT = (b'\xb4\xd0\xea\xfb\xfb\xf6s\xcc\x10\xc4\x99\x95"\x13 y\xa6\xea.G\xeed\x8d=t9\x88|\x94\xd1\xbcK\xd47'
b'\xd8\xbcG1h\xac\xd0\xeb*\x1f\x8d\xae\x0b\x91G\xa1\xe6\x96b\xf2\xda90u\xeb_\xab\xdb\xcb%d7}\xb5\xce'
b'(k\x15\xe3L\x9d)\xd5\xa1|:')
INTER_SHARED_SECRET = (b'vf\xd82\xaeU\xda]\x08\x9eZ\xd6\x06\xcc\xd3\x99\xfd\xce\xc5\x16e8n\x9a\x04\x04\x84\xc5\x1a'
b'\x8f\xf2M')
BOX_SECRET = b'\x03\xfe\xe3\x8c u\xbcl^\x17eD\x96\xa3\xa6\x880f\x11\x7f\x85\xf2:\xa3[`\x06[#l\xbcr'
SHARED_SECRET = b'UV\xad*\x8e\xce\x88\xf2\x87l\x13iZ\x12\xd7\xa6\xd1\x9c-\x9d\x07\xf5\xa96\x03w\x11\xe5\x96$m\x1d'
CLIENT_ENCRYPT_KEY = (b'\xec\x1f,\x82\x9f\xedA\xc0\xda\x87[\xf9u\xbf\xac\x9cI\xa5T\xd1\x91\xff\xa8.\xd0 \xfbU\xc7\x14'
b')\xc7')
CLIENT_DECRYPT_KEY = b'\xf9e\xa0As\xb2=\xb7P~\xf3\xf9(\xfd\x7f\xfe\xb7TZhn\xd7\x8c=\xea.o\x9e\x8c9)\x10'
CLIENT_ENCRYPT_NONCE = b'S\\\x06\x8d\xe5\xeb&*\xb8\x0bp\xb3Z\x8e\\\x85\x14\xaa\x1c\x8di\x9d\x7f\xa9'
CLIENT_DECRYPT_NONCE = b'd\xe8\xccD\xec\xb9E\xbb\xaa\xa7\x7f\xe38\x15\x16\xef\xca\xd22u\x1d\xfe<\xe7'
def test_handshake(client, server):
client_challenge = client.generate_challenge()
assert client_challenge == CLIENT_CHALLENGE
assert server.verify_challenge(client_challenge)
server_challenge = server.generate_challenge()
assert server_challenge == SERVER_CHALLENGE
assert client.verify_server_challenge(server_challenge)
assert client.shared_secret == INTER_SHARED_SECRET
client_auth = client.generate_client_auth()
assert client_auth == CLIENT_AUTH
assert server.verify_client_auth(client_auth)
assert server.shared_secret == client.shared_secret
server_accept = server.generate_accept()
assert server_accept == SERVER_ACCEPT
assert client.verify_server_accept(server_accept)
assert client.box_secret == BOX_SECRET
assert client.box_secret == server.box_secret
client_keys = client.get_box_keys()
server_keys = server.get_box_keys()
assert client_keys['shared_secret'] == SHARED_SECRET
assert client_keys['encrypt_key'] == CLIENT_ENCRYPT_KEY
assert client_keys['decrypt_key'] == CLIENT_DECRYPT_KEY
assert client_keys['encrypt_nonce'] == CLIENT_ENCRYPT_NONCE
assert client_keys['decrypt_nonce'] == CLIENT_DECRYPT_NONCE
assert client_keys['shared_secret'] == server_keys['shared_secret']
assert client_keys['encrypt_key'] == server_keys['decrypt_key']
assert client_keys['encrypt_nonce'] == server_keys['decrypt_nonce']

53
secret_handshake/util.py Normal file
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import struct
# Stolen from PyCypto (Public Domain)
def b(s):
return s.encode("latin-1") # utf-8 would cause some side-effects we don't want
def long_to_bytes(n, blocksize=0):
"""long_to_bytes(n:long, blocksize:int) : string
Convert a long integer to a byte string.
If optional blocksize is given and greater than zero, pad the front of the
byte string with binary zeros so that the length is a multiple of
blocksize.
"""
# after much testing, this algorithm was deemed to be the fastest
s = b('')
pack = struct.pack
while n > 0:
s = pack('>I', n & 0xffffffff) + s
n = n >> 32
# strip off leading zeros
for i in range(len(s)):
if s[i] != b('\000')[0]:
break
else:
# only happens when n == 0
s = b('\000')
i = 0
s = s[i:]
# add back some pad bytes. this could be done more efficiently w.r.t. the
# de-padding being done above, but sigh...
if blocksize > 0 and len(s) % blocksize:
s = (blocksize - len(s) % blocksize) * b('\000') + s
return s
def bytes_to_long(s):
"""bytes_to_long(string) : long
Convert a byte string to a long integer.
This is (essentially) the inverse of long_to_bytes().
"""
acc = 0
unpack = struct.unpack
length = len(s)
if length % 4:
extra = (4 - length % 4)
s = b('\000') * extra + s
length = length + extra
for i in range(0, length, 4):
acc = (acc << 32) + unpack('>I', s[i:i+4])[0]
return acc