🔑 Single Sign On (SSO): The Magic Token That Opens Every Door!

🎬 The Story Begins...

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Meet Fred, the IT team lead at a small company. Fred’s job? Keeping things secure. He’s like the guardian of the digital castle, making sure that only the right people get in.

One morning, while sipping his coffee, Fred notices something weird.

His team is drowning in passwords. Every tool they use—CRM, marketing platforms, project management—needs a different login. Keeping track of all that? A nightmare.

Then a question hits him:

"What if someone reuses passwords… or worse, steals a login?"

But fear not! There’s a solution. Time to pop open the hood on something called Single-Sign-On (SSO)—a tool that eliminates password chaos.

🔑 SSO: The Master Key That Does It All

Fred’s Dilemma

Imagine Fred’s office as a huge building with locked doors everywhere. Normally, each employee would need a different key for every single door. Annoying, right?

But what if, instead of juggling dozens of keys, there was one master key that opened every door you were allowed to enter?

That’s SSO (Single Sign-On).

The SSO Everyone Knows: Google SSO

When you see "Google Sign-in" or "Sign-in with Google", this is SSO. Precisely: it is Google's own implementation of SSO.

Google SSO is like a VIP security guard. When you log in with your Google account, it's like the guard checking your ID once and saying:

"Okay, you’re good! Here’s a special badge that works on all your doors—no need to stop and check again!"

And just like that, you’re in. But how does this actually work?

The Secret Behind the Magic Badge

Let’s examine Fred’s badge under a security microscope.

On this badge, Google writes:

• Fred’s name: “Fred, the IT Manager”
• Where he’s allowed to go: CRM, project tools, marketing platforms
• An expiration date: Because nothing lasts forever

The catch? This badge isn’t just printed—it’s digitally signed by Google. It’s like an official seal of approval that apps can trust. In a technical language, we call this a token.

Now, when Fred tries to access an app, it doesn’t ask for a password. Instead, it just scans the badge/token and says:

✔️ “Was this issued by Google? Yes.”

✔️ “Does Fred have permission? Yes.”

✔️ “Access granted.”

But wait… what stops someone from making a fake token?

🛡️ Why Can’t Hackers Fake It?

Imagine trying to fake a backstage pass to a VIP concert.

The pass might look real, but when security scans it… Busted.

Why? Because VIP passes are digitally signed, just like Fred’s SSO token.

• If a fake token isn’t signed by Google? Rejected.
• If an old token is expired? Nice try.

That’s why Google SSO is secure—only Google can issue these passes, and apps check their authenticity every single time.

⚙️ What Happens When You Log in with Google SSO?

Let’s go behind the scenes.

1️⃣ Fred tries to log into an app. The app says:

“Sorry, I don’t handle logins. Go ask Google.”

2️⃣ Google asks Fred for his credentials. He logs in (preferably with two-factor authentication).

3️⃣ Google gives Fred a token.

4️⃣ Fred presents the token to the app. The app scans it and says:

✔️ “Google confirms this is real.”

✔️ “Fred is allowed in.”

5️⃣ Fred gets access—without entering a password.

And the best part? Fred doesn’t have to log in again for every app: Google remembers Fred is signed-in and will only challenge his session if the context changes, such as a different browser, or a different IP / location.

🔍 Bonus: The Power of Permissions

Fred’s token can also come with special permissions.

Example: The marketing team wants to connect their app to Fred’s calendar.

The app asks Google:

"Hey, does Fred’s token allow me to see his calendar?"

Google checks… If Fred said yes, then boom—the app gets access.

If not? Denied.

This is where OAuth and permissions come into play. But for now, let’s focus on authentication!

🌍 SSO: It’s Bigger Than Google!

Fred’s starting to see the magic of SSO—but then another thought pops into his head.

"Wait… is Google the only one doing this?"

Not at all! SSO isn’t just a Google thing—it’s a universal concept. The idea behind it—one login to access multiple services—works across many platforms.

The Big Names in SSO

Just like there are different brands of cars, computers, and coffee, there are different SSO providers. Here are some of the biggest players:

• Microsoft Entra ID (formerly Azure AD) – A top choice for companies using Microsoft 365, Windows, and Azure Cloud.
• Okta & Auth0 – Cloud-native SSO providers known for their strong security and wide compatibility with other apps.
• AWS IAM Identity Center – Amazon’s SSO for managing access to AWS services and third-party apps.
• OneLogin – A flexible option for companies using a mix of tools from different vendors.
• You can even build your own! - Here’s an open source example of a simple implementation of an SSO central authorization server using 500 lines of Node.js: https://github.com/ankur-anand/simple-sso

🎉 What Did We Learn Today?

✅ SSO = One Login to Rule Them All

✅ Google SSO = Just a specific type of SSO everyone uses all the time

✅ Tokens = Secure Digital Badges

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Fred leans back in his chair, finally at peace knowing that his company is secure and his team isn’t drowning in passwords anymore.

Now, he can focus on real IT work… like figuring out why the printer only breaks on Mondays.

See you next time for more adventures! Stay secure.