How can I convert a python urandom to a string?

Question

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'x8bzxaf$xb6x93qxefx94x99$x8cx1eOxebxedx03Oxc6L%xe70xf9xd8
xa4xacx01xe1xb5x0bM#x19xea+x81xdcxcbxed7Oxecxf5\}x029x122
x8bxbdxa9xcaxb2x88r+x88xf0xeaEx9c'

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.

Asked By: user1876508

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Source

Answer 1

You have random bytes; I’d be very surprised if that ever was decodable to a string.

If you have to have a unicode string, decode from Latin-1:

a.decode('latin1')

because it maps bytes one-on-one to corresponding Unicode code points.

Answered By: Martijn Pieters

Answer 2

You can use base-64 encoding. In this case:

a = os.urandom(64)
a.encode('base-64')

Also note that I’m using encode here rather than decode, as decode is trying to take it from whatever format you specify into unicode. So in your example, you’re treating the random bytes as if they form a valid utf-8 string, which is rarely going to be the case with random bytes.

Answered By: Rob Watts

Answer 3

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')

Answered By: user1876508

Answer 4

this easy way:

a = str(os.urandom(64))
print(F"the: {a}")
print(type(a))

Answered By: Ahmad Al ALloush

Answer 5

Are you sure that you need 64 bytes represented as string?

Maybe what you really need is N-bits token?
If so, use secrets. The secrets module provides functions for generating secure tokens, suitable for applications such as password resets, hard-to-guess URLs, and similar.

import secrets

>>> secrets.token_bytes(16)  
b'xebrx17D*txaexd4xe3Sxb6xe2xebP1x8b'

>>> secrets.token_hex(16)  
'f9bf78b9a18ce6d46a0cd2b0b86df9da'

>>> secrets.token_urlsafe(16)  
'Drmhze6EPcv0fN_81Bj-nA'

Or Maybe you need 64 chars length random string? import string

import secrets
alphabet = string.ascii_letters + string.digits
password = ''.join(secrets.choice(alphabet) for i in range(64))

Answered By: Alexander C

How can I convert a python urandom to a string?

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