Check playlist
### OAuth 2.0 explained with examples
**Core Insights & Summary:**
* **Purpose of OAuth 2.0:** It is an authorization protocol designed to allow third-party applications to access protected resources on behalf of a user without requiring their password [00:00:00].
* **Access Tokens:** The system relies on "Access Tokens," which are short-lived credentials that act like a key. These tokens specify exactly what the application can access and for how long [00:01:51].
* **Roles in the Ecosystem:** The flow involves the Resource Owner (user), the Client (the app), the Authorization Server (e.g., Google/Facebook), and the Resource Server (the API holding the data) [00:03:57].
* **Security via JWT:** OAuth 2.0 often uses JSON Web Tokens (JWT) because they are self-contained, compact, and easily verified by resource servers [00:04:42].
**Real-Time Example:**
* When you want to play a new mobile game and it asks you to "Login with Google," you are using OAuth 2.0. You login to Google directly; Google then gives the game an **Access Token**. The game uses that token to get your username or profile picture from Google’s servers without ever seeing your actual Google password [00:01:31].
**Analytical Takeaway:**
* OAuth 2.0 is the modern standard for delegated access. It significantly improves security by limiting the "blast radius"—if a third-party app is compromised, only the specific access token is leaked, not the user's master password [00:03:43].
### What is SAML? A Comprehensive Guide with Examples
**Core Insights & Summary:**
* **Nature of SAML:** Security Assertion Markup Language (SAML) is an XML-based open standard used for exchanging authentication and authorization data [00:00:00].
* **Single Sign-On (SSO):** SAML's primary strength is enabling SSO, allowing a user to log in once and gain access to multiple different applications [00:01:12].
* **Identity vs. Service Provider:** The "Identity Provider" (IDP) authenticates the user, while the "Service Provider" (SP) relies on the IDP's "SAML Assertion" (a signed XML document) to grant access [00:01:41].
* **Security through Signatures:** SAML assertions are digitally signed, ensuring that the identity information cannot be tampered with while in transit between providers [00:05:03].
**Real-Time Example:**
* In a corporate setting, an employee logs into their company’s portal (IDP). Because of SAML, they can then click on **Salesforce, Slack, or Workday** and be logged in instantly. The company portal sends a signed XML document to Salesforce saying, "This is John, and he is a verified manager," and Salesforce trusts it immediately [00:06:57].
**Analytical Takeaway:**
* SAML remains the "gold standard" for enterprise and high-security sectors like healthcare and government. Unlike OAuth (which is better for app-to-app data sharing), SAML provides a robust, highly-trusted framework for identity federation across entire organizations [00:09:19].
3. What Happens When You Login? (IAM Secrets)
**Core Insights & Summary**
Identity and Access Management (IAM) is the framework that ensures the right people have the right access to resources.
It answers two questions: **"Who are you?"** (Authentication/AuthN) and **"What can you do?"** (Authorization/AuthZ) [00:00:06].
The process involves an Identity Provider (IdP) like Okta or Google that verifies credentials and issues a secure token
(SAML or OIDC) to the Service Provider (SP) [00:01:44].
**Real-Time Example**
When you use **"Sign in with Google"** to access GitHub, Google acts as the IdP [00:01:16]. GitHub trusts
Google’s assertion that you are who you say you are, allowing you to log in without GitHub ever seeing your
Google password [00:01:29].
**Analytical Takeaway**
IAM enables **Federation**, allowing a single identity to be used across multiple independent systems [00:03:21].
Centralizing this via an IdP reduces "password sprawl" and simplifies offboarding: disabling a user in the central IdP
revokes their access across all federated apps instantly [00:03:51].
4. JSON Web Tokens (JWTs) Explained
**Core Insights & Summary**
JWT is an open standard for securely transmitting information as a JSON object [00:00:00]. Unlike stateful
session tokens stored in a server database, JWTs are **stateless**; the token itself contains all the
necessary user data (claims) [00:01:59]. A JWT consists of three parts: **Header** (algorithm info),
**Payload** (user data/claims), and **Signature** (verification) [00:04:40].
**Real-Time Example**
Imagine a **concert wristband** [00:02:11]. The security guard doesn't need to check a master list every time
you move between sections; they just look at your wristband to see your "claims" (e.g., VIP access) and verify
the "signature" (the band's unique tamper-evident seal).
**Analytical Takeaway**
The most common misconception is that JWTs hide data. They are **encoded and signed, not encrypted** [00:11:01].
Anyone can decode a JWT and read the payload (e.g., at jwt.io) [00:09:34]. The security lies in the
**Signature**—if a malicious user changes their role from "user" to "admin," the signature becomes
invalid because it no longer matches the payload [00:10:41].
5. HTTPS, SSL, & TLS Handshake
**Core Insights & Summary**
HTTPS is HTTP running over the **TLS (Transport Layer Security)** protocol [00:06:26]. It solves the
**Man-in-the-Middle (MITM)** attack by encrypting data between the client and server [00:01:13]. The process
uses **Asymmetric Encryption** (Public/Private keys) to securely exchange a **Symmetric Key**, which
is then used for the actual data transfer because it is much faster [00:04:18].
**Real-Time Example**
The **TLS Handshake**: The client says "Hello," the server responds with its **SSL Certificate** [00:07:38].
The client verifies this certificate with a trusted **Certificate Authority (CA)** (like DigiCert) to ensure
the server isn't an impostor [00:10:18]. Once verified, they agree on a secret "Session Key" [00:09:01].
**Analytical Takeaway**
Trust is the foundation of HTTPS. We trust the server because a **Certificate Authority** has digitally
signed the server's public key [00:11:01]. If a browser doesn't recognize the CA, it flags the site
as "Not Secure" [00:12:10].
6. What is mTLS? (Mutual TLS)
**Core Insights & Summary**
In standard TLS, only the server proves its identity to the client [00:01:13]. In **Mutual TLS (mTLS)**,
the client must *also* present a certificate to the server [00:00:00]. This creates a "Zero Trust" environment
where neither side is trusted until their certificate is verified [00:04:42].
**Real-Time Example**
In a **Microservices architecture**, Service A (Billing) needs to talk to Service B (Database) [00:03:28].
Using mTLS ensures that Service B *only* accepts requests from Service A (and other authorized services),
preventing an internal attacker from spoofing a service to steal data [00:03:36].
**Analytical Takeaway**
mTLS is the gold standard for **Service-to-Service communication**. While it adds complexity due to
certificate management (every service needs its own cert), it effectively eliminates unauthorized internal
traffic and protects against compromised credentials [00:05:16].
7. SCIM: The Identity Protocol
**Core Insights & Summary**
**SCIM (System for Cross-domain Identity Management)** is a protocol for automating user provisioning [00:00:14].
While SAML/OIDC handles *how you log in*, SCIM handles *how your account is created/updated* in the
first place [00:01:36]. It uses a standard REST API to sync user data between an IdP and various apps [00:01:45].
**Real-Time Example**
When an HR system marks an employee as "Hired," the IdP (e.g., Okta) uses SCIM to automatically
create their accounts in **Slack, Gmail, and Salesforce** [00:01:15]. When they leave, SCIM
instantly deactivates those accounts everywhere [00:08:09].
**Analytical Takeaway**
Large organizations often build a **Centralized Identity Sync Service** [00:03:29]. Instead of every
internal app implementing a complex SCIM listener, they talk to one central hub that manages the
"Source of Truth" and pushes updates to downstream systems via Kafka or Webhooks [00:05:14].
