mirror of
https://github.com/markqvist/Reticulum.git
synced 2024-11-07 14:50:15 +00:00
100 lines
3.2 KiB
Python
100 lines
3.2 KiB
Python
# MIT License
|
|
#
|
|
# Copyright (c) 2022 Mark Qvist / unsigned.io
|
|
#
|
|
# 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 os
|
|
import time
|
|
|
|
from RNS.Cryptography import HMAC
|
|
from RNS.Cryptography import PKCS7
|
|
from RNS.Cryptography.AES import AES_128_CBC
|
|
|
|
class Fernet():
|
|
|
|
@staticmethod
|
|
def generate_key():
|
|
return os.urandom(32)
|
|
|
|
def __init__(self, key = None):
|
|
if key == None:
|
|
raise ValueError("Fernet key cannot be None")
|
|
|
|
if len(key) != 32:
|
|
raise ValueError("Fernet key must be 32 bytes, not "+str(len(key)))
|
|
|
|
self._signing_key = key[:16]
|
|
self._encryption_key = key[16:]
|
|
|
|
|
|
def verify_hmac(self, token):
|
|
if len(token) <= 32:
|
|
raise ValueError("Cannot verify HMAC on token of only "+str(len(token))+" bytes")
|
|
else:
|
|
received_hmac = token[-32:]
|
|
expected_hmac = HMAC.new(self._signing_key, token[:-32]).digest()
|
|
|
|
if received_hmac == expected_hmac:
|
|
return True
|
|
else:
|
|
return False
|
|
|
|
|
|
def encrypt(self, data = None):
|
|
iv = os.urandom(16)
|
|
current_time = int(time.time())
|
|
|
|
if not isinstance(data, bytes):
|
|
raise TypeError("Fernet token plaintext input must be bytes")
|
|
|
|
ciphertext = AES_128_CBC.encrypt(
|
|
plaintext = PKCS7.pad(data),
|
|
key = self._encryption_key,
|
|
iv = iv,
|
|
)
|
|
|
|
signed_parts = b"\x80"+current_time.to_bytes(length=8, byteorder="big")+iv+ciphertext
|
|
|
|
return signed_parts + HMAC.new(self._signing_key, signed_parts).digest()
|
|
|
|
|
|
def decrypt(self, token = None):
|
|
if not isinstance(token, bytes):
|
|
raise TypeError("Fernet token must be bytes")
|
|
|
|
if not self.verify_hmac(token):
|
|
raise ValueError("Fernet token HMAC was invalid")
|
|
|
|
iv = token[9:25]
|
|
ciphertext = token[25:-32]
|
|
|
|
try:
|
|
plaintext = PKCS7.unpad(
|
|
AES_128_CBC.decrypt(
|
|
ciphertext,
|
|
self._encryption_key,
|
|
iv,
|
|
)
|
|
)
|
|
|
|
return plaintext
|
|
|
|
except Exception as e:
|
|
raise ValueError("Could not decrypt Fernet token") |