from __future__ import absolute_import
"""
M2Crypto wrapper for OpenSSL BN (BIGNUM) API.
Copyright (c) 2005 Open Source Applications Foundation. All rights reserved.
"""
from M2Crypto import m2
from typing import Optional # noqa
[docs]
def rand(bits, top=-1, bottom=0):
# type: (int, int, int) -> Optional[int]
"""
Generate cryptographically strong random number.
:param bits: Length of random number in bits.
:param top: If -1, the most significant bit can be 0. If 0, the most
significant bit is 1, and if 1, the two most significant
bits will be 1.
:param bottom: If bottom is true, the number will be odd.
"""
return m2.bn_rand(bits, top, bottom)
[docs]
def rand_range(range):
# type: (int) -> int
"""
Generate a random number in a range.
:param range: Upper limit for range.
:return: A random number in the range [0, range)
"""
return m2.bn_rand_range(range)
[docs]
def randfname(length):
# type: (int) -> str
"""
Return a random filename, which is simply a string where all
the characters are from the set [a-zA-Z0-9].
:param length: Length of filename to return.
:return: random filename string
"""
import warnings
warnings.warn(
"Don't use BN.randfname(), use tempfile methods instead.",
DeprecationWarning, stacklevel=2)
letters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890'
lettersLen = len(letters)
fname = [] # type: list
for x in range(length):
fname += [letters[m2.bn_rand_range(lettersLen)]]
return ''.join(fname)