OXIESEC PANEL

Name	Size	Modified	Perms
📁 ..	-	12/11/2024 09:39:44 AM	rwxr-xr-x
📄 __init__.py	1.51 KB	04/05/2021 03:08:16 PM	rw-r--r--
📁 __pycache__	-	02/11/2025 08:19:48 AM	rwxr-xr-x
📄 _compat.py	4.24 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 asn1.py	1.74 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 cli.py	8.99 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 common.py	4.46 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 core.py	1.62 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 key.py	23.96 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 machine_size.py	2.3 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 parallel.py	2.27 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 pem.py	3.48 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 pkcs1.py	14.35 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 pkcs1_v2.py	3.38 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 prime.py	4.95 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 randnum.py	2.58 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 transform.py	6.44 KB	04/05/2021 03:08:16 PM	rw-r--r--
📄 util.py	2.99 KB	04/05/2021 03:08:16 PM	rw-r--r--

Editing: common.py

# -*- coding: utf-8 -*-
#
#  Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

from rsa._compat import zip

"""Common functionality shared by several modules."""

class NotRelativePrimeError(ValueError):
    def __init__(self, a, b, d, msg=None):
        super(NotRelativePrimeError, self).__init__(
            msg or "%d and %d are not relatively prime, divider=%i" % (a, b, d))
        self.a = a
        self.b = b
        self.d = d

def bit_size(num):
    """
    Number of bits needed to represent a integer excluding any prefix
    0 bits.

Usage::

>>> bit_size(1023)
        10
        >>> bit_size(1024)
        11
        >>> bit_size(1025)
        11

:param num:
        Integer value. If num is 0, returns 0. Only the absolute value of the
        number is considered. Therefore, signed integers will be abs(num)
        before the number's bit length is determined.
    :returns:
        Returns the number of bits in the integer.
    """

try:
        return num.bit_length()
    except AttributeError:
        raise TypeError('bit_size(num) only supports integers, not %r' % type(num))

def byte_size(number):
    """
    Returns the number of bytes required to hold a specific long number.

The number of bytes is rounded up.

Usage::

>>> byte_size(1 << 1023)
        128
        >>> byte_size((1 << 1024) - 1)
        128
        >>> byte_size(1 << 1024)
        129

:param number:
        An unsigned integer
    :returns:
        The number of bytes required to hold a specific long number.
    """
    if number == 0:
        return 1
    return ceil_div(bit_size(number), 8)

def ceil_div(num, div):
    """
    Returns the ceiling function of a division between `num` and `div`.

Usage::

>>> ceil_div(100, 7)
        15
        >>> ceil_div(100, 10)
        10
        >>> ceil_div(1, 4)
        1

:param num: Division's numerator, a number
    :param div: Division's divisor, a number

:return: Rounded up result of the division between the parameters.
    """
    quanta, mod = divmod(num, div)
    if mod:
        quanta += 1
    return quanta

def extended_gcd(a, b):
    """Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jb
    """
    # r = gcd(a,b) i = multiplicitive inverse of a mod b
    #      or      j = multiplicitive inverse of b mod a
    # Neg return values for i or j are made positive mod b or a respectively
    # Iterateive Version is faster and uses much less stack space
    x = 0
    y = 1
    lx = 1
    ly = 0
    oa = a  # Remember original a/b to remove
    ob = b  # negative values from return results
    while b != 0:
        q = a // b
        (a, b) = (b, a % b)
        (x, lx) = ((lx - (q * x)), x)
        (y, ly) = ((ly - (q * y)), y)
    if lx < 0:
        lx += ob  # If neg wrap modulo orignal b
    if ly < 0:
        ly += oa  # If neg wrap modulo orignal a
    return a, lx, ly  # Return only positive values

def inverse(x, n):
    """Returns the inverse of x % n under multiplication, a.k.a x^-1 (mod n)

>>> inverse(7, 4)
    3
    >>> (inverse(143, 4) * 143) % 4
    1
    """

(divider, inv, _) = extended_gcd(x, n)

if divider != 1:
        raise NotRelativePrimeError(x, n, divider)

return inv

def crt(a_values, modulo_values):
    """Chinese Remainder Theorem.

Calculates x such that x = a[i] (mod m[i]) for each i.

:param a_values: the a-values of the above equation
    :param modulo_values: the m-values of the above equation
    :returns: x such that x = a[i] (mod m[i]) for each i

>>> crt([2, 3], [3, 5])
    8

>>> crt([2, 3, 2], [3, 5, 7])
    23

>>> crt([2, 3, 0], [7, 11, 15])
    135
    """

m = 1
    x = 0

for modulo in modulo_values:
        m *= modulo

for (m_i, a_i) in zip(modulo_values, a_values):
        M_i = m // m_i
        inv = inverse(M_i, m_i)

x = (x + a_i * M_i * inv) % m

return x

if __name__ == '__main__':
    import doctest

doctest.testmod()