def __init__(self, seed=None, keysize=32, cipher=AES):
'''Constructor
seed = seed (will auto-generate if not specified)
keysize = keysize of underlying block cipher (default = 32 bytes)
cipher = Class for block cipher (default: AES)
'''
self.__drbg = CTRDRBG(cipher, keysize)
if (seed is None) or (len(seed) == 0):
seed = Random.__generate_seed(1024)
microseconds = round(time() * 1000000)
nonce = microseconds.to_bytes(12, byteorder='big')
personalization = b'MJR CTR-DRBG'
self.__drbg._Instantiate(seed, nonce, personalization)
# To detect a later fork
self.__pid = getpid()
class Random(object):
'''The interface for random byte generator'''
def __init__(self, seed=None, keysize=32, cipher=AES):
'''Constructor
seed = seed (will auto-generate if not specified)
keysize = keysize of underlying block cipher (default = 32 bytes)
cipher = Class for block cipher (default: AES)
'''
self.__drbg = CTRDRBG(cipher, keysize)
if (seed is None) or (len(seed) == 0):
seed = Random.__generate_seed(1024)
microseconds = round(time() * 1000000)
nonce = microseconds.to_bytes(12, byteorder='big')
personalization = b'MJR CTR-DRBG'
self.__drbg._Instantiate(seed, nonce, personalization)
# To detect a later fork
self.__pid = getpid()
@staticmethod
def __generate_seed(numbytes):
'''Generates a default seed
Uses urandom because otherwise @tqbf will
complain'''
return urandom(numbytes)
def get_bytes(self, numbytes):
if (self.__pid != getpid()):
# fork() happened -- reseed
self.__drbg._Reseed(self.__generate_seed(1024), None)
self.__pid = getpid()
try:
rand = self.__drbg._Generate(numbytes, None)
except AssertionError:
# resseed required
self.__drbg._Reseed(self.__generate_seed(1024), None)
rand = self.__drbg._Generate(numbytes, None)
return rand
