HTTP and HTTPS in HLD - Architecture Diagram

System Overview - HTTP and HTTPS

This system explains how HTTP and HTTPS protocols work to deliver web content securely and efficiently. HTTP is the basic protocol for web communication, while HTTPS adds encryption to protect data during transfer.

Key requirements include secure data transmission, fast response times, and compatibility with web browsers and servers.

Architecture Diagram

Internet

↓

Load Balancer

↓

Web Server

↓

Application Server

↓

Cache

↓

Database

Components

User

client

Sends HTTP or HTTPS requests using a web browser

Internet

network

Transports requests and responses between user and servers

Load Balancer

load_balancer

Distributes incoming requests evenly across web servers

Web Server

service

Handles HTTP/HTTPS requests, terminates TLS for HTTPS, and serves static content

Application Server

service

Processes business logic and dynamic content generation

Cache

cache

Stores frequently accessed data to reduce database load and improve response time

Database

database

Stores persistent application data

Request Flow - 10 Hops

User → Load Balancer

Load Balancer → Web Server

Web Server → Application Server

Application Server → Cache

Cache → Application Server

Application Server → Database

Database → Application Server

Application Server → Web Server

Web Server → Load Balancer

Load Balancer → User

Failure Scenario

Component Fails:Load Balancer

Impact:All incoming user requests fail to reach web servers, causing complete service outage

Mitigation:Use multiple load balancers with failover and health checks to ensure availability

Architecture Quiz - 3 Questions

Which component is responsible for encrypting and decrypting HTTPS traffic?

A Load Balancer

B Web Server

C Application Server

D Cache

Design Principle

This architecture demonstrates secure web communication by using HTTPS with TLS termination at the web server, combined with load balancing for scalability and caching to improve performance. It separates concerns clearly and ensures data protection during transmission.

Practice

1. What is the main difference between HTTP and HTTPS?

easy

A. HTTPS encrypts data while HTTP does not

B. HTTP encrypts data while HTTPS does not

C. HTTP is faster because it uses encryption

D. HTTPS does not use any encryption

Solution

1. Step 1: Understand HTTP basics

   HTTP transfers data without encryption, so data can be seen by others.

2. Step 2: Understand HTTPS encryption

   HTTPS adds encryption to protect data from being read by others during transfer.

3. Final Answer:

   HTTPS encrypts data while HTTP does not -> Option A

4. Quick Check:

   Encryption = HTTPS [OK]

Hint: HTTPS always means encrypted data transfer [OK]

Common Mistakes:

• Thinking HTTP encrypts data
• Believing HTTPS is slower because of encryption
• Confusing HTTP and HTTPS roles

2. Which URL prefix indicates a secure connection using HTTPS?

easy

A. http://

B. https://

C. ftp://

D. file://

Solution

1. Step 1: Identify URL prefixes

   URLs starting with http:// use HTTP, which is not secure.

2. Step 2: Recognize HTTPS prefix

   URLs starting with https:// use HTTPS, which is secure and encrypted.

3. Final Answer:

   https:// -> Option B

4. Quick Check:

   Secure URL prefix = https:// [OK]

Hint: Secure URLs start with https:// [OK]

Common Mistakes:

• Choosing http:// as secure
• Confusing ftp:// with HTTPS
• Not recognizing URL prefixes

3. Consider this simplified request flow for a website:

1. Client sends HTTP request
2. Server responds with redirect to HTTPS URL
3. Client sends HTTPS request
4. Server sends secure response

What is the main purpose of step 2 in this flow?

medium

A. To encrypt data before sending it

B. To send the website content unencrypted

C. To close the connection immediately

D. To tell the client to use a secure connection

Solution

1. Step 1: Analyze step 2 action

   Server sends a redirect response telling client to change URL to HTTPS.

2. Step 2: Understand redirect purpose

   This redirect forces client to use a secure encrypted connection for next request.

3. Final Answer:

   To tell the client to use a secure connection -> Option D

4. Quick Check:

   Redirect to HTTPS = secure connection [OK]

Hint: Redirects to HTTPS enforce secure connections [OK]

Common Mistakes:

• Thinking redirect encrypts data itself
• Believing redirect closes connection
• Confusing redirect with content delivery

4. A developer wrote this code snippet to check if a URL uses HTTPS:

if url.startswith('http://'):
    print('Secure connection')
else:
    print('Not secure')

What is the error in this code?

medium

A. It should check for 'https://' to confirm security

B. The print statements are reversed

C. The method 'startswith' does not exist

D. It should use 'http://' to confirm security

Solution

1. Step 1: Understand the check logic

   The code checks if URL starts with 'http://', then says 'Secure connection'.

2. Step 2: Identify correct prefix for security

   Only URLs starting with 'https://' are secure, so the check is wrong.

3. Final Answer:

   It should check for 'https://' to confirm security -> Option A

4. Quick Check:

   Check 'https://' for security [OK]

Hint: Check for 'https://' prefix to confirm security [OK]

Common Mistakes:

• Confusing 'http://' as secure
• Reversing print messages
• Using non-existent string methods

5. You are designing a web service that must protect user data and build trust. Which approach best ensures secure communication and user confidence?

hard

A. Use HTTP and encrypt data manually in the application layer

B. Use HTTP for faster data transfer and add a login page

C. Use HTTPS with a valid SSL certificate and redirect all HTTP requests to HTTPS

D. Use HTTPS only on the login page and HTTP elsewhere

Solution

1. Step 1: Identify security needs

   Protecting user data requires encryption for all communication, not just parts.

2. Step 2: Evaluate options for secure design

   Using HTTPS with a valid SSL certificate and redirecting HTTP to HTTPS ensures all data is encrypted and users see trust indicators.

3. Final Answer:

   Use HTTPS with a valid SSL certificate and redirect all HTTP requests to HTTPS -> Option C

4. Quick Check:

   Full HTTPS with redirect = best security [OK]

Hint: Always redirect HTTP to HTTPS with valid SSL for trust [OK]

Common Mistakes:

• Using HTTP for speed over security
• Encrypting only parts of communication
• Mixing HTTP and HTTPS causing confusion