If you’re building any application that involves user accounts, there’s one security rule you absolutely cannot break: never, ever store passwords in plaintext. A single database breach could expose every user’s password, leading to a catastrophic loss of trust and security. The correct way to handle passwords is to hash them. In this guide, we’ll walk through the best way to do this in Python using the bcrypt library.

So, what’s wrong with common hashing algorithms like MD5 or SHA-1? They were designed to be fast. That’s great for verifying file integrity, but terrible for passwords. A fast algorithm means an attacker can try billions of password combinations per second against your leaked hashes. We need something that is intentionally slow. Enter bcrypt.

Bcrypt is a password-hashing function designed by Niels Provos and David Mazières. It has several key features that make it the gold standard for password security:

• It’s Slow: By design, bcrypt is computationally expensive. This drastically slows down brute-force attacks.
• It Includes Salt: Bcrypt automatically generates and incorporates a “salt” (a random string) into each hash. This means that even if two users have the same password, their stored hashes will be completely different.
• It’s Adaptive: As computers get faster, you can increase the “cost factor” of bcrypt to make it even slower, keeping pace with hardware improvements.