# random.py
#
# Copyright (C) 2006-2018 wolfSSL Inc.
#
# This file is part of wolfSSL. (formerly known as CyaSSL)
#
# wolfSSL 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; either version 2 of the License, or
# (at your option) any later version.
#
# wolfSSL 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
# pylint: disable=no-member,no-name-in-module
from wolfcrypt._ffi import ffi as _ffi
from wolfcrypt._ffi import lib as _lib
from wolfcrypt.exceptions import WolfCryptError
[docs]class Random(object):
"""
A Cryptographically Secure Pseudo Random Number Generator - CSPRNG
"""
def __init__(self):
self.native_object = _ffi.new("WC_RNG *")
ret = _lib.wc_InitRng(self.native_object)
if ret < 0: # pragma: no cover
self.native_object = None
raise WolfCryptError("RNG init error (%d)" % ret)
def __del__(self):
if self.native_object:
try:
_lib.wc_FreeRng(self.native_object)
except AttributeError: # pragma: no cover
# Can occur during interpreter shutdown
pass
[docs] def byte(self):
"""
Generate and return a random byte.
"""
result = _ffi.new('byte[1]')
ret = _lib.wc_RNG_GenerateByte(self.native_object, result)
if ret < 0: # pragma: no cover
raise WolfCryptError("RNG generate byte error (%d)" % ret)
return _ffi.buffer(result, 1)[:]
[docs] def bytes(self, length):
"""
Generate and return a random sequence of length bytes.
"""
result = _ffi.new('byte[%d]' % length)
ret = _lib.wc_RNG_GenerateBlock(self.native_object, result, length)
if ret < 0: # pragma: no cover
raise WolfCryptError("RNG generate block error (%d)" % ret)
return _ffi.buffer(result, length)[:]