Python | os.getrandom() method

OS module in Python provides functions for interacting with the operating system. OS comes under Python’s standard utility modules. This module provides a portable way of using operating system dependent functionality.

os.getrandom() method is used to generate a string of size random bytes suitable for cryptographic use or we can say this method generates a string containing random characters. It can also be used to seed user-space random number generators. It can return less bytes than requested.

Syntax: os.getrandom(size, flag)

Parameter:
size: It is the size of string random bytes
flag: It is a bit mask that can contain zero or more flags ORed together. Flags are os.GRND_RANDOM and GRND_NONBLOCK.

Return Value: This method returns a string which represents random bytes suitable for cryptographic use.

Flags –

os.GRND_NONBLOCK: If this flag is set then getrandom() does not block but instead immediately raises BlockingIOError if no random bytes are available to read.

os.GRND_RANDOM: If this bit is set then random bytes are drawn from the /dev/random pool.

Example #1 :

# Python program to explain os.getrandom() method

# importing os module
import os

# Declaring size
size = 5

# Using os.getrandom() method
# Using os.GRND_NONBLOCK flag
result = os.getrandom(size, os.GRND_NONBLOCK)

# Print the random bytes string
# Output will be different everytime
print(result)

Output:

b'5\n\xe0\x98\x15'

Example #2 :

# Python program to explain os.getrandom() method

# importing os module
import os

# Declaring size
size = 5

# Using os.getrandom() method
# Using os.GRND_RANDOM flag
result = os.getrandom(size, os.GRND_RANDOM)

# Print the random bytes string
# Output will be different everytime
print(result)

Output:

b'\xce\xc8\xf3\x95%'