Whats the difference between os.urandom() and random?

Question

On the random module python page (Link Here) there is this warning:

Warning: The pseudo-random generators of this module should not b

Answer 1

So whats the difference between os.urandom() and random?

Random itself is predicable. That means that given the same seed the sequence of numbers generated by random is the same. Take a look at this question for a better explanation. This question also illustrates than random isn't really random.

This is generally the case for most programming languages - the generation of random numbers is not truly random. You can use these numbers when cryptographic security is not a concern or if you want the same pattern of numbers to be generated.

Is one closer to a true random than the other?

Not sure how to answer this question because truly random numbers cannot be generated. Take a look at this article or this question for more information.

Since random generates a repeatable pattern I would say that os.urandom() is certainly more "random"

Would the secure random be overkill in non-cryptographic instances?

I wrote the following functions and there doesn't appear to be a huge time difference. However, if you don't need cryptographically secure numbers it doesn't really make sense to use os.urandom(). Again it comes down to the use case, do you want a repeatable pattern, how "random" do you want your numbers, etc?

import time
import os
import random


def generate_random_numbers(x): 
  start = time.time()
  random_numbers = []
  for _ in range(x):
    random_numbers.append(random.randrange(1,10,1))
  end = time.time()
  print(end - start)


def generate_secure_randoms(x):
  start = time.time()
  random_numbers = []
  for _ in range(x):
    random_numbers.append(os.urandom(1))
  end = time.time()
  print(end - start)


generate_random_numbers(10000)
generate_secure_randoms(10000)

Results:

0.016040563583374023
0.013456106185913086

Are there any other random modules in python?

Python 3.6 introduces the new secrets module