Building an E2EE Chat App in Flask - Part 2: Secure Password Storage

Avash Karn — Fri, 22 May 2026 09:26:50 +0000

Hey everyone! Part 1 explained encryption. Now let's secure passwords.

The Problem: Plain Text Passwords

In my first version, I stored passwords like this:

if user and user.password == p_word:
    # LOGIN

This is TERRIBLE because:

If database leaks, everyone's passwords exposed
No hashing = no protection
One breach = account takeover

The Solution: Werkzeug Password Hashing

Use werkzeug.security to hash passwords:

Registration:

from werkzeug.security import generate_password_hash

hashed_password = generate_password_hash(password)
user = User(username=username, password=hashed_password)
db.session.add(user)
db.session.commit()

Login:

from werkzeug.security import check_password_hash

user = User.query.filter_by(username=username).first()
if user and check_password_hash(user.password, password):
    session['logged_in'] = True
    # USER LOGGED IN

Why This Works

Passwords are hashed (one-way)
Hash can't be reversed
Even if leaked, passwords stay safe
Industry standard
Built into Flask ecosystem

What I Learned

Passwords must NEVER be stored in plain text. Ever.

Part 3 Coming

File uploads and validation.

Questions? Drop them below!

Building an E2EE Chat App in Flask - Part 1: Why Encryption Matters

Avash Karn — Fri, 22 May 2026 07:33:47 +0000

Hey everyone! I'm building an encrypted chat application in Flask and documenting the journey. Here's Part 1.
Why E2EE Matters
Most messaging apps claim to be secure, but they're not. Your messages sit on their servers where anyone with access can read them.

End-to-End Encryption (E2EE) = only you and the recipient can read messages. The server can't see anything.

Example:
WhatsApp uses E2EE. Facebook Messenger doesn't. Your choice matters.

Why I Built This
I wanted to understand encryption by building it, not just reading about it. This project taught me way more than any tutorial.

What's Next
Part 2: How to handle passwords safely without storing them in plain text.

Questions? Drop them in comments!

DEV Community: Avash Karn