How can I convert a python urandom to a string?

user1876508 picture user1876508 · Jul 31, 2013 · Viewed 31k times · Source

If I call os.urandom(64), I am given 64 random bytes. With reference to Convert bytes to a Python string I tried

a = os.urandom(64)
a.decode()
a.decode("utf-8")

but got the traceback error stating that the bytes are not in utf-8.

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 0: invalid start byte

with the bytes

b'\x8bz\xaf$\xb6\x93q\xef\x94\x99$\x8c\x1eO\xeb\xed\x03O\xc6L%\xe70\xf9\xd8
\xa4\xac\x01\xe1\xb5\x0bM#\x19\xea+\x81\xdc\xcb\xed7O\xec\xf5\\}\x029\x122
\x8b\xbd\xa9\xca\xb2\x88\r+\x88\xf0\xeaE\x9c'

Is there a fullproof method to decode these bytes into some string representation? I am generating sudo random tokens to keep track of related documents across multiple database engines.

Answer

user1876508 picture user1876508 · Feb 21, 2014

The code below will work on both Python 2.7 and 3:

from base64 import b64encode
from os import urandom

random_bytes = urandom(64)
token = b64encode(random_bytes).decode('utf-8')