def random_bytes(byte_count):
rng = SystemRandom()
return bytes(rng.choices(range(256), k=byte_count))
class RandomOracle(object):
QRNG_API_URL = 'https://qrng.anu.edu.au/API/jsonI.php'
def __init__(self, seed=None, use_qrn=False, qrn_n_preload=1024):
# Random() can be seeded for reproducability but should not be used in
# real world applications.
self._random = SystemRandom() if seed is None else Random(seed)
# Storage for oracles
self._mapping = {}
# ANU QRNG api
self._qrn_data = []
self._qrn_n_preload = qrn_n_preload
self._use_qrn = use_qrn
if use_qrn:
print('rng source: ANU QRNG api')
self._qrn_preload()
elif seed is None:
print('rng source: secrets.SystemRandom')
else:
print('rng source: random.Random')
"""
Use the ANU QRNG api to fetch an array of quantum random numbers.
See: https://qrng.anu.edu.au/
"""
def _qrn_preload(self):
print(f'buffering {self._qrn_n_preload} quantum random numbers..')
try:
data = requests.get(self.QRNG_API_URL, {
'length': self._qrn_n_preload,
'type': 'hex16',
'size': 32
}).json()
self._qrn_data = data['data']
except:
print('Error fetching data from ANU QRNG api')
exit(1)
"""
Return n quantum random numbers
"""
def _qrn(self, n=3):
# If there's a buffer underflow preload some numbers from the api
if len(self._qrn_data) < n:
self._qrn_preload()
return [int(self._qrn_data.pop(), 16) for x in range(n)]
"""
Apply a quadratic function with random parameters to input i
"""
def _qf(self, i):
x, y, z = list(self._qrn()) if self._use_qrn else list(
self._random.choices(range(0, sys.maxsize), k=3))
return ((x * i)**2) + (y * i) + z
"""
Generate an oracle for input i, store it and truncate the output to the
desired number of digits.
"""
def rand(self, i, digits=64):
data = self._mapping.get(i, {})
p = [data.get('out', '')]
c = len(p)
while c < digits:
s = str(self._qf(i))
c += len(s)
p.append(s)
o = ''.join(p)
self._mapping[i] = {"in": i, "out": o[:digits], "digits": digits}
return self._mapping[i]
