`secrets`

The Python secrets module provides a straightforward and secure way to generate cryptographically strong random numbers suitable for managing sensitive data, such as passwords, account credentials, security tokens, and related secrets.

Here’s a quick example:

>>> import secrets
>>> # Generate a secure random number
>>> secrets.randbelow(10)
4

Key Features

Generates cryptographically secure random numbers
Provides functions to generate secure tokens
Offers functions to compare secrets in a way that reduces the risk of timing attacks

Frequently Used Classes and Functions

Object	Type	Description
`secrets.token_bytes()`	Function	Generates a random byte string
`secrets.token_hex()`	Function	Generates a random text string, in hexadecimal
`secrets.token_urlsafe()`	Function	Generates a random URL-safe text string
`secrets.choice()`	Function	Returns a randomly chosen element from a non-empty sequence
`secrets.randbelow()`	Function	Returns a random int in the range [0, n)
`secrets.randbits()`	Function	Returns a non-negative int with k random bits
`secrets.compare_digest()`	Function	Compares two strings in constant time to reduce the risk of timing attacks
`secrets.SystemRandom`	Class	Generates random numbers using the highest-quality sources provided by the operating system
`secrets.DEFAULT_ENTROPY`	Constant	Default number of bytes of randomness used by the module’s `token_*` functions when `nbytes` is omitted or `None`

Examples

Generate a random byte string:

>>> secrets.token_bytes(16)
b'1Y\x80\x10rG \xa9J\xd0\x9c\x9f\x13\xd3\x98\xb1'

Generate a random text string in hexadecimal:

>>> secrets.token_hex(16)
'2befb22f1581dd4ede4821e6252d1359'

Generate a random URL-safe text string:

>>> secrets.token_urlsafe(16)
'JOQrXog1v_aK6QgZp9Lxrg'

Common Use Cases

Generating secure tokens for session management
Creating cryptographically secure passwords
Comparing sensitive data in a secure manner

Real-World Example

Suppose you’re building a web application and need to generate secure tokens for user sessions. Here’s how you can use the secrets module to create a token:

>>> import secrets
>>> token = secrets.token_urlsafe(32)
>>> print(f"Your session token is: {token}")
Your session token is: eMWcxNGqfiucn-SjezajTtOEX7M5D81n3rRL6r06yxM

In this example, the secrets module generates a secure, random URL-safe token suitable for managing user sessions.

Tutorial

Generating Random Data in Python (Guide)

You'll cover a handful of different options for generating random data in Python, and then build up to a comparison of each in terms of its level of security, versatility, purpose, and speed.

intermediate data-science python

For additional information on related topics, take a look at the following resources: