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-rw-r--r--freestyle_hid/_freestyle_encryption.py67
-rw-r--r--freestyle_hid/_session.py48
2 files changed, 75 insertions, 40 deletions
diff --git a/freestyle_hid/_freestyle_encryption.py b/freestyle_hid/_freestyle_encryption.py
index 0461cb8..a0268eb 100644
--- a/freestyle_hid/_freestyle_encryption.py
+++ b/freestyle_hid/_freestyle_encryption.py
@@ -6,7 +6,7 @@
class SpeckEncrypt:
def __init__(self, key):
# Perform key expansion and store the round keys
- self.key = key & ((2 ** 128) - 1)
+ self.key = key & ((2**128) - 1)
self.key_schedule = [self.key & 0xFFFFFFFF]
key_buf = [(self.key >> (x * 32)) & 0xFFFFFFFF for x in range(1, 4)]
for x in range(26):
@@ -58,13 +58,19 @@ class SpeckEncrypt:
def encrypt(self, iv, plain):
plain = bytearray(plain)
input_length = len(plain)
- plain.extend(bytes(b'\x00' * (8 - (input_length % 8))))
- iv = int.from_bytes(iv.to_bytes(8, byteorder='big'), byteorder='little', signed=False)
+ plain.extend(bytes(b"\x00" * (8 - (input_length % 8))))
+ iv = int.from_bytes(
+ iv.to_bytes(8, byteorder="big"), byteorder="little", signed=False
+ )
output = bytearray()
for i in range(len(plain) // 8):
k = self.encrypt_block(iv)
- res = k ^ int.from_bytes(plain[i*8:i*8+8], byteorder='little', signed=False)
- output.extend(int.to_bytes(res, 8, byteorder='little', signed=False))
+ slice_start = i * 8
+ slice_end = slice_start + 8
+ res = k ^ int.from_bytes(
+ plain[slice_start:slice_end], byteorder="little", signed=False
+ )
+ output.extend(int.to_bytes(res, 8, byteorder="little", signed=False))
iv += 1
encrypted = output[:input_length]
return bytes(encrypted)
@@ -72,24 +78,30 @@ class SpeckEncrypt:
def decrypt(self, iv, encrypted):
return self.encrypt(iv, encrypted)
-class SpeckCMAC:
+class SpeckCMAC:
def __init__(self, key):
self.cipher = SpeckEncrypt(key)
k0 = self.cipher.encrypt_block(0)
- k0 = int.from_bytes(k0.to_bytes(8, byteorder='big'), byteorder='little', signed=False)
+ k0 = int.from_bytes(
+ k0.to_bytes(8, byteorder="big"), byteorder="little", signed=False
+ )
- k1 = (k0 << 1) & 0XFFFFFFFFFFFFFFFF
- if (k0 >> 63 != 0):
+ k1 = (k0 << 1) & 0xFFFFFFFFFFFFFFFF
+ if k0 >> 63 != 0:
k1 ^= 0x1B
- k2 = (k1 << 1) & 0XFFFFFFFFFFFFFFFF
- if (k1 >> 63 != 0):
+ k2 = (k1 << 1) & 0xFFFFFFFFFFFFFFFF
+ if k1 >> 63 != 0:
k2 ^= 0x1B
- k1 = int.from_bytes(k1.to_bytes(8, byteorder='big'), byteorder='little', signed=False)
- k2 = int.from_bytes(k2.to_bytes(8, byteorder='big'), byteorder='little', signed=False)
+ k1 = int.from_bytes(
+ k1.to_bytes(8, byteorder="big"), byteorder="little", signed=False
+ )
+ k2 = int.from_bytes(
+ k2.to_bytes(8, byteorder="big"), byteorder="little", signed=False
+ )
self.k1 = k1
self.k2 = k2
@@ -98,22 +110,33 @@ class SpeckCMAC:
i = 0
data_len = len(data)
- while (i < data_len):
+ while i < data_len:
data_left = data_len - i
- if (data_left == 8):
- block = int.from_bytes(data[i:i+8], 'little') ^ self.k1
- elif (data_left < 8):
- block = int.from_bytes(data[i:i+data_left] + b'\x80' + b'\x00'*(7-data_left), 'little') ^ self.k2
+ slice_start = i
+ slice_end = slice_start + 8
+ if data_left == 8:
+ block = int.from_bytes(data[slice_start:slice_end], "little") ^ self.k1
+ elif data_left < 8:
+ slice_end = i + data_left
+ block = (
+ int.from_bytes(
+ data[slice_start:slice_end]
+ + b"\x80"
+ + b"\x00" * (7 - data_left),
+ "little",
+ )
+ ^ self.k2
+ )
else:
- block = int.from_bytes(data[i:i+8], 'little')
+ block = int.from_bytes(data[slice_start:slice_end], "little")
c = self.cipher.encrypt_block(c ^ block)
i += 8
return c
def derive(self, label, context):
- data = label + b'\x00' + context + b'\x80\x00'
- d1 = self.sign(b'\x01' + data)
- d2 = self.sign(b'\x02' + data) << 64
+ data = label + b"\x00" + context + b"\x80\x00"
+ d1 = self.sign(b"\x01" + data)
+ d2 = self.sign(b"\x02" + data) << 64
return d1 | d2
diff --git a/freestyle_hid/_session.py b/freestyle_hid/_session.py
index 581f3fe..cdfca42 100644
--- a/freestyle_hid/_session.py
+++ b/freestyle_hid/_session.py
@@ -11,15 +11,15 @@ from typing import AnyStr, Callable, Iterator, Optional, Sequence, Tuple
import construct
from ._exceptions import ChecksumError, CommandError
+from ._freestyle_encryption import SpeckCMAC, SpeckEncrypt
from ._hidwrapper import HidWrapper
-from ._freestyle_encryption import SpeckEncrypt, SpeckCMAC
ABBOTT_VENDOR_ID = 0x1A61
-_AUTH_ENC_MASTER_KEY = 0xdeadbeef
-_AUTH_MAC_MASTER_KEY = 0xdeadbeef
-_SESS_ENC_MASTER_KEY = 0xdeadbeef
-_SESS_MAC_MASTER_KEY = 0xdeadbeef
+_AUTH_ENC_MASTER_KEY = 0xDEADBEEF
+_AUTH_MAC_MASTER_KEY = 0xDEADBEEF
+_SESS_ENC_MASTER_KEY = 0xDEADBEEF
+_SESS_MAC_MASTER_KEY = 0xDEADBEEF
_INIT_COMMAND = 0x01
_INIT_RESPONSE = 0x71
@@ -142,30 +142,36 @@ class Session:
assert response[0] == _ENCRYPTION_SETUP_RESPONSE
assert response[1][0] == 0x16
reader_rand = response[1][1:9]
- iv = int.from_bytes(response[1][9:16], 'big', signed=False)
+ iv = int.from_bytes(response[1][9:16], "big", signed=False)
driver_rand = random.randbytes(8)
resp_enc = auth_enc.encrypt(iv, reader_rand + driver_rand)
resp_mac = auth_mac.sign(b"\x14\x1a\x17" + resp_enc + b"\x01")
- resp_mac = int.to_bytes(resp_mac, 8, byteorder='little', signed=False)
- self.send_command(_ENCRYPTION_SETUP_COMMAND, b"\x17" + resp_enc + b"\x01" + resp_mac)
+ resp_mac = int.to_bytes(resp_mac, 8, byteorder="little", signed=False)
+ self.send_command(
+ _ENCRYPTION_SETUP_COMMAND, b"\x17" + resp_enc + b"\x01" + resp_mac
+ )
response = self.read_response()
assert response[0] == _ENCRYPTION_SETUP_RESPONSE
assert response[1][0] == 0x18
mac = auth_mac.sign(b"\x33\x22" + response[1][:24])
- mac = int.to_bytes(mac, 8, byteorder='little', signed=False)
+ mac = int.to_bytes(mac, 8, byteorder="little", signed=False)
assert mac == response[1][24:32]
- iv = int.from_bytes(response[1][17:24], 'big', signed=False)
+ iv = int.from_bytes(response[1][17:24], "big", signed=False)
resp_dec = auth_enc.decrypt(iv, response[1][1:17])
assert resp_dec[:8] == driver_rand
assert resp_dec[8:] == reader_rand
crypt = SpeckCMAC(_SESS_ENC_MASTER_KEY)
- ses_enc_key = crypt.derive("SessnEnc".encode(), serial + reader_rand + driver_rand)
+ ses_enc_key = crypt.derive(
+ "SessnEnc".encode(), serial + reader_rand + driver_rand
+ )
crypt = SpeckCMAC(_SESS_MAC_MASTER_KEY)
- ses_mac_key = crypt.derive("SessnMAC".encode(), serial + reader_rand + driver_rand)
+ ses_mac_key = crypt.derive(
+ "SessnMAC".encode(), serial + reader_rand + driver_rand
+ )
self.crypt_enc = SpeckEncrypt(ses_enc_key)
self.crypt_mac = SpeckCMAC(ses_mac_key)
- #print("HANDSHAKE SUCCESSFUL!")
+ # print("HANDSHAKE SUCCESSFUL!")
def connect(self):
if self._encrypted_protocol:
@@ -186,15 +192,15 @@ class Session:
# Not giving a f**k about the IV counter for now
output[57:61] = bytes(4)
mac = self.crypt_mac.sign(output[1:61])
- output[61:65] = int.to_bytes(mac, 8, byteorder='little', signed=False)[4:]
+ output[61:65] = int.to_bytes(mac, 8, byteorder="little", signed=False)[4:]
return bytes(output)
def decrypt_message(self, packet: bytes):
output = bytearray(packet)
mac = self.crypt_mac.sign(packet[:60])
- mac = int.to_bytes(mac, 8, byteorder='little', signed=False)[4:]
+ mac = int.to_bytes(mac, 8, byteorder="little", signed=False)[4:]
assert mac == packet[60:64]
- iv = int.from_bytes(packet[56:60], 'big', signed=False) << 8
+ iv = int.from_bytes(packet[56:60], "big", signed=False) << 8
output[1:56] = self.crypt_enc.decrypt(iv, packet[1:56])
return bytes(output)
@@ -210,7 +216,10 @@ class Session:
{"message_type": message_type, "command": command}
)
- if self._encrypted_protocol and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES:
+ if (
+ self._encrypted_protocol
+ and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES
+ ):
usb_packet = self.encrypt_message(usb_packet)
logging.debug(f"Sending packet: {usb_packet!r}")
@@ -225,7 +234,10 @@ class Session:
assert usb_packet
message_type = usb_packet[0]
- if self._encrypted_protocol and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES:
+ if (
+ self._encrypted_protocol
+ and message_type not in _ALWAYS_UNENCRYPTED_MESSAGES
+ ):
usb_packet = self.decrypt_message(usb_packet)
message_length = usb_packet[1]