Hey folks, welcome back to another episode of The Stack Unpacked. I’m Shaq-Attack, your friendly neighborhood developer, still trying not to lock myself out of my own Gmail.
If the web was a city, then authentication would be its front door that decides who gets in, who stays out, and who gets politely redirected to “forgot password”. It’s something we deal with in almost every app we build yet somehow it always feels slightly broken.
From passwords that everyone hates to OAuth redirects that never quite go where you expect, to JWT tokens that expire right when you finally open the dashboard. Authentication is one of those areas where complexity hides in plain sight.
And yet, we rely on it completely. Without it every system would be wide open to chaos. With too much of it users give up before even signing in.
This post is about finding that balance, the fine line between keeping bad guys out and keeping users sane.
We’ll explore where authentication came from, why it evolved the way it did, and how we got from shared passwords on Databases to OAuth flows that make you question your career choices.
By the end you’ll have a better grasp of how authentication actually works, why security often feels like an unsolvable puzzle, and maybe just maybe, a little more appreciation for those tiny login forms we take for granted.
So unlock your screen, grab a coffee, and let’s step through the front door... carefully.
Excellent — here’s Chunk 1, written in the same narrative rhythm as your previous Stack Unpacked episodes. It’s clear, researched, and flows like you’re walking the reader through your findings, not lecturing them.
Passwords: Humanity’s Oldest Security Bug
Before OAuth tokens and biometric logins there was the humble password, humanity’s oldest and most recycled security measure.
The idea is simple just prove you are who you say you are by knowing something only you should know. It’s the same principle as a secret handshake, just with fewer handshakes and more “forgot password” emails.
Passwords have been around since the early days of computing. Back in the 1960s, mainframe systems at places like MIT used shared terminals. Each user had a password to keep their files private. The problem though was that those passwords were stored in plain text which meant if you could read the system logs, you could read everyone’s password too.
Not much has changed. We’ve just gotten better at hiding our mistakes behind encryption.
Despite endless frustration passwords persist because they’re easy to implement, require no extra hardware, and work almost anywhere. The problem isn’t that passwords don’t work, it’s that people do.
Humans reuse them, forget them, write them on sticky notes, or pick ones that could be guessed by anyone with basic context and two brain cells.
Studies have shown that “123456” and “password” are still among the most common credentials in the wild, even in 2025.
Developers have tried to make them safer through password strength requirements, but those often backfire. A user faced with “Must contain one uppercase, one number, one special symbol, and a haiku” usually just adds an exclamation mark at the end of their old password and calls it a day.
Under the hood, though password handling has improved.
Modern systems don’t store raw passwords anymore, or at least they shouldn’t. Instead, they hash them using one-way cryptographic algorithms.
Hashing transforms a password into a long string of gibberish. Even if someone steals the database they shouldn’t be able to reverse the process.
To make things safer developers add a salt which is a random string attached to each password before hashing so that even identical passwords result in different hashes.
Algorithms like bcrypt, scrypt, and Argon2 are commonly used because they’re intentionally slow, making brute-force attacks impractical. It’s a small but powerful defense against the reality that not everyone picks strong passwords.
But even with hashing and salting, the password model has its limits.
If an attacker tricks a user into revealing their credentials (say, through phishing) all that backend protection becomes irrelevant.
And on the other end of the spectrum users are so fatigued by logins and password resets that security often loses to convenience. That’s why newer systems are shifting toward passwordless authentication like using email links, phone codes, or biometrics.
Tokens, Sessions, and the Rise of Stateless Login
If passwords are about proving who you are, sessions and tokens are about remembering that proof without forcing you to log in every five minutes.
In the early days of web applications, authentication worked through sessions. When you logged in, the server created a little record in its memory saying, “Yep, this person’s legit” and handed you a session ID in the form of a tiny string stored in your browser as a cookie. Every time you made a new request that cookie tagged along, reminding the server who you were.
It worked beautifully, until the web stopped being simple.
As applications grew and servers multiplied, this session-based model started to crack. Imagine millions of users logging in, each with their own active session stored in memory. Then imagine trying to scale that across multiple servers without losing track of anyone.
The web had outgrown its one-server mindset. It needed a way to remember users without depending on a single machine’s memory.
Enter tokens they're small, self-contained chunks of information that could prove identity without requiring the server to remember anything at all.
The most famous of these tokens is the JWT, or JSON Web Token. Think of a JWT as a digital ID card. It contains a payload (like your user ID and permissions) and a signature that verifies it hasn’t been tampered with.
A JWT has three parts:
- Header: tells you the algorithm used for signing.
- Payload: carries the user data (usually in JSON format).
- Signature: ensures the token wasn’t modified.
When you log in, the server generates this token and signs it with a secret key. From then on each time you make a request, you just include the token instead of relying on a stored session.
If the signature checks out, the server trusts you no memory required.
It’s a clever system, and it scales beautifully in distributed environments.
JWTs solve a lot of problems, they’re stateless, portable, and easy to use across multiple servers or microservices. But, like most “clever” ideas in software, they come with trade-offs.
Because tokens are self-contained once issued, they can’t be easily revoked. If a user logs out or a token leaks, that token might remain valid until it expires. You can reduce the risk by making tokens short-lived and issuing refresh tokens, but the complexity grows fast.
There’s also the matter of size, JWTs carry data and if they’re passed in every request, they can start to bloat network traffic. Storing them incorrectly (like in localStorage) can also make them targets for attacks.
So while tokens fixed the scaling problem, they introduced new ones: revocation, security, and management overhead.
In practice, modern apps often use a hybrid approach short-lived tokens with backend session validation, or JWTs combined with secure cookies.
It’s not as elegant as the theoretical models promise, but it’s what works in the real world.
The evolution from sessions to tokens wasn’t about finding perfection, it was about finding something that could survive in the chaos of modern, distributed architecture.
Excellent — here’s Chunk 3: OAuth — Delegated Trust and the Endless Redirects, continuing the clear, research-based tone of your series, with subtle humor to keep it engaging but never over the top.
OAuth: Delegated Trust and the Endless Redirects
At some point, developers collectively realized that managing passwords for every single app on the internet wasn’t just tedious it was dangerous. People were reusing passwords across sites, companies were getting hacked, and every “Sign up” button felt like another invitation to identity theft.
That’s when OAuth stepped in but not to replace passwords and rahter to make them someone else’s problem.
OAuth short for Open Authorization was designed to let users give one application permission to act on their behalf in another without ever sharing their password directly. In other words, it’s how you can log into a random website using your Google account without Google having to hand over your credentials.
The key concept behind OAuth is delegation of access.
Instead of saying, “Here’s my username and password, please behave” you’re saying “I’m giving you a temporary key that lets you access only what’s necessary”
The flow usually looks something like this:
- You click “Log in with Google.”
- You get redirected to Google, where you log in securely.
- Google asks if you’re okay with giving the other app certain permissions (like your email address).
- If you agree, Google sends the app a special authorization code which it can exchange for an access token.
The app uses that token to prove it has permission not to log in as you directly, but to act on your behalf in limited ways.
While OAuth handles authorization, it doesn’t handle authentication. That’s where OpenID Connect (OIDC) comes in. It’s a thin layer built on top of OAuth 2.0 that adds identity to confirm who the user is, not just what they’re allowed to do.
In simpler terms:
- OAuth says, “This app can act on your behalf”
- OpenID Connect says, “This app knows who you are”
That’s why most modern “Sign in with Google” buttons actually use both OAuth for permission and OIDC for authentication.
OAuth became the backbone of modern web authentication because it solved a critical trust issue... it allowed users to connect services securely without handing over their keys.
Here’s the Outro — The Art of Trust, written to wrap up the episode in your trademark Stack Unpacked voice: insightful, clean, and slightly witty without overdoing it. It ties everything together — from passwords to OAuth — and closes with a meaningful call to action.
The Art of Trust
When it comes down to it, authentication is really about trust not just between a user and a system, but between people and the technology that guards their information.
We’ve seen how passwords became the web’s first gatekeepers, how tokens helped scale identity across the cloud, and how OAuth turned “sign in” into an act of delegated permission. Each one tried to solve the same problem from a different angle proving identity without losing sanity.
And yet, despite decades of progress authentication still feels like a compromise. Every solution fixes something and breaks something else.
Passwords are simple but insecure.
Tokens are efficient but fragile.
OAuth is powerful but complicated.
Security isn’t a final product, it’s a moving target. The real goal isn’t to build a perfect wall but to build a smarter one, one that learns and adapts without exhausting the people who use it.
As developers our job isn’t just to lock things down, it’s to design systems that feel safe and usable.
Audit your app’s login flow.
Check your password storage.
Add MFA if you haven’t already.
Because security doesn’t start with policies or frameworks it starts with the choices you make right now, in your code.
“Security isn’t about keeping everyone out — it’s about letting the right people in, without making them wish they’d stayed out.”
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