Day 20 in 40 Days of Kubernetes: Understanding HTTP and HTTPS
Introduction
Before managing TLS certificates in Kubernetes, it's essential to understand how HTTP, HTTPS, SSL, and TLS work. This knowledge is fundamental for ensuring secure communication over the internet.
In today's interconnected world, securing communication over the internet is crucial for protecting sensitive information. Whether you're browsing your favorite social media site or making an online purchase, the protocols that manage data transfer between your browser and the web server play a vital role in safeguarding your data. In this blog, we'll explore HTTP and HTTPS, explain their differences, discuss why HTTPS is preferred for secure communication, and delve into the roles of SSL (Secure Sockets Layer) and TLS (Transport Layer Security) in the process.
How HTTP Works
HTTP (Hypertext Transfer Protocol) is the fundamental protocol used for transmitting data across the web. It operates as a request-response protocol in the client-server model.
Basic Steps of HTTP:
Client Request: When a user enters a URL in the browser, the browser sends an HTTP request to the server hosting the website.
Server Response: The server processes the request and sends back the requested resources (such as HTML, CSS, JavaScript, images) to the client's browser.
Rendering: The browser receives the response and renders the web page for the user to view.
Example of HTTP:
Suppose you want to visit "example.com". Here’s what happens:
You type the URL in your browser and press Enter.
The browser sends an HTTP request to the server where "example.com" is hosted.
The server processes this request and responds with the website’s resources.
Your browser then displays the website.
Problem with HTTP:
HTTP transmits data in plain text, which makes it vulnerable to interception and tampering by malicious actors. Sensitive information like passwords, credit card numbers, and personal data can be easily compromised during transmission over HTTP.
Transition to HTTPS
To address the security issues inherent in HTTP, HTTPS (Hypertext Transfer Protocol Secure) was introduced. HTTPS uses encryption to protect data during transmission, ensuring that it cannot be easily intercepted or tampered with.
How HTTPS Works:
HTTPS builds on HTTP by adding a layer of security through SSL/TLS protocols.
Step-by-Step Process of HTTPS:
TCP Handshake: Before any secure communication, a TCP handshake establishes a reliable connection.
SSL/TLS Handshake: This handshake involves several steps to establish a secure connection using asymmetric and symmetric encryption.
SSL/TLS Handshake Process:
Client Hello: The client sends a message to the server, indicating supported SSL/TLS versions and cipher suites.
Server Hello: The server responds, choosing the SSL/TLS version and cipher suite to be used.
Server Certificate: The server sends its SSL/TLS certificate containing its public key.
Certificate Validation: The client validates the server's certificate with the CA (Certificate Authority).
Client Key Exchange: The client generates a session key (symmetric key), encrypts it with the server's public key, and sends it to the server.
Change Cipher Spec: Both the client and server send a message to switch to encrypted communication using the session key.
Finished: Both parties send a message indicating the handshake is complete, encrypted with the session key.
SSL/TLS Certification
SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are cryptographic protocols designed to provide secure communication over a computer network.
SSL: The original protocol, now deprecated due to security vulnerabilities.
TLS: An improved version of SSL, offering enhanced security.
Key Concepts in SSL/TLS:
Asymmetric Encryption: Utilizes a pair of keys (public and private). The public key encrypts data, while the private key decrypts it. This method ensures secure key exchange.
Symmetric Encryption: Uses a single key for both encryption and decryption. This method is efficient for data transmission.
Example of HTTPS in Action:
User Request: A user enters "examplebank.com" in their browser.
TCP Handshake: The client and server establish a TCP connection.
Client Hello: The client initiates the SSL/TLS handshake.
Server Hello: The server responds and sends its certificate.
Certificate Validation: The client validates the server's certificate with the CA (Certificate Authority).
Client Key Exchange:
The server generates both a public key and a private key.
The server sends its public key to the client.
The client generates a session key (symmetric key) and encrypts it with the server's public key.
The client sends this encrypted session key to the server.
Session Key Creation:
The server receives the encrypted session key and decrypts it using its private key.
Now, both the client and server have the session key.
Change Cipher Spec: Both the client and server switch to encrypted communication using the session key.
Secure Data Transfer: The client and server communicate securely using symmetric encryption with the session key.
This process ensures that the user's data is securely transmitted, maintaining confidentiality, integrity, and authentication.
Conclusion
In summary, while HTTP is suitable for basic web communication, its lack of security makes it inadequate for transmitting sensitive information. HTTPS, enhanced by SSL/TLS protocols, provides the necessary encryption to ensure data security. Understanding the mechanics of HTTP and HTTPS, along with the encryption processes involved, is crucial for appreciating the importance of secure web communication.