Authentication Best Practices

What this best practices guide is

A practical guide to authentication for developers who build their own sign-in or need to review one. It covers password rules and storage, the login flow and brute force protection, multi-factor authentication, passkeys, session handling, and account recovery, following NIST SP 800-63B-4 and the OWASP cheat sheets.

It has 6 chapters and 25 practices, each with why it matters, what to do and what to avoid. For developers who build sign-in and accounts.

Chapter by chapter

1. Password rules and storage (4 practices)

What passwords to accept, what to reject, and how to store them so a database leak does not hand out working credentials.

2. The login flow and brute force protection (4 practices)

How the sign-in endpoint should respond, how to slow down guessing without locking real users out, and what to record.

3. Multi-factor authentication (5 practices)

Which second factors to offer, how to stop attackers getting around them, and how recovery and factor changes should work.

4. Passkeys and WebAuthn (3 practices)

Passkeys replace passwords with a key pair bound to your site. The browser does the hard cryptography, but your server still has checks to get right.

5. Sessions and cookies (5 practices)

After sign-in, the session token is the credential. These practices keep it unguessable, out of reach of scripts, and short-lived.

6. Account recovery and sensitive actions (4 practices)

Password reset and account changes are second ways into every account. They need the same care as the login itself.

How it works on Sefism

The guide reads like a short course: a syllabus, then one chapter per page in a focused reader, with a quiz at the end of each chapter for members. The opening chapters are open to everyone. Adding it to your account uses credits, opens every chapter and keeps your progress.

Every claim is checked against the sources listed on the page (8 cited).