mirror of
https://github.com/elseif/MikroTikPatch.git
synced 2025-01-23 05:25:00 +03:00
60 lines
1.9 KiB
Python
60 lines
1.9 KiB
Python
#
|
|
# toyecc - A small Elliptic Curve Cryptography Demonstration.
|
|
# Copyright (C) 2011-2022 Johannes Bauer
|
|
#
|
|
# This file is part of toyecc.
|
|
#
|
|
# toyecc is free software; you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation; this program is ONLY licensed under
|
|
# version 3 of the License, later versions are explicitly excluded.
|
|
#
|
|
# toyecc is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with toyecc; if not, write to the Free Software
|
|
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
#
|
|
# Johannes Bauer <JohannesBauer@gmx.de>
|
|
#
|
|
|
|
from .FieldElement import FieldElement
|
|
|
|
class CRT():
|
|
"""Implements the Chinese Remainder Theorem algorithm where a number of
|
|
modular congruences are given that all need to be satisfied."""
|
|
def __init__(self):
|
|
self._moduli = { }
|
|
|
|
def add(self, value, modulus):
|
|
"""Adds a value that shall be returned when the result is taken modulo
|
|
the given modulus."""
|
|
assert(modulus not in self._moduli)
|
|
assert(isinstance(value, int))
|
|
assert(isinstance(modulus, int))
|
|
self._moduli[modulus] = value
|
|
return self
|
|
|
|
def solve(self):
|
|
"""Solve the Chinese Remainder Theorem for the given values and
|
|
moduli."""
|
|
# Calculate product of all moduli
|
|
product = 1
|
|
for modulus in self._moduli.keys():
|
|
product *= modulus
|
|
|
|
# Then determine the solution
|
|
solution = 0
|
|
for modulus in self._moduli.keys():
|
|
if self._moduli[modulus] == 0:
|
|
continue
|
|
|
|
rem_product = product // modulus
|
|
one_value = int(FieldElement(rem_product, modulus).inverse())
|
|
solution += rem_product * one_value * self._moduli[modulus]
|
|
|
|
return solution % product
|