The 6 Differences Between HTTP and HTTPS

HTTP (Hypertext Transfer Protocol) and HTTPS (Hypertext Transfer Protocol Secure) primarily differ in terms of security and data transmission. HTTPS is the secure version of HTTP, which encrypts data transmission using the SSL/TLS protocol, ensuring the security and integrity of data during transmission, thus preventing interception or tampering of data. In contrast, data transmitted via HTTP is unencrypted, making it more susceptible to interception by third parties. Additionally, HTTPS requires the use of certificates to verify the server's identity, thereby enhancing communication trust. Although their purposes are similar, there are several key differences between the two.

Introduction to HTTP (Hypertext Transfer Protocol)

What is HTTP?

HTTP (Hypertext Transfer Protocol) is an application layer protocol used to transfer hypertext from a server to a local browser. It is a request-response protocol that facilitates communication between a client user agent (typically a web browser) and a server serving as an information resource. It forms the basis of World Wide Web (WWW) data communication, primarily used for loading web pages. While HTTP follows a stateless protocol, it often maintains state within sessions using mechanisms such as cookies.

How Does HTTP Work?

The working mechanism of HTTP can be summarized in the following steps:

1. Client Request: When a user enters a URL or clicks a link in a browser, the browser sends an HTTP request to the server. An HTTP request typically consists of: a request line (including methods like GET, POST, the URL of the resource, and HTTP version), request headers (including client environment information such as accepted content types), and an optional request body (usually used for POST requests containing data to be sent to the server).
2. Server Response: Upon receiving the client's request, the server processes it and returns an HTTP response. The response typically includes: a status line (including HTTP version, status code, and status explanation), response headers (including server information, content types, etc.), and a response body (the actual content requested by the client, such as a webpage or other data).
3. Connection Establishment: Before sending a request, the client needs to establish a connection with the server. In HTTP/1.1 and earlier versions, each request/response pair typically required a new TCP connection, leading to additional latency. To improve performance, HTTP/1.1 introduced persistent connections ("keep-alive"), allowing multiple requests/responses to be sent/received over a single connection, while HTTP/2 further introduced multiplexing.
4. Rendering: Once the browser receives the server's response, it parses the response and renders the page based on the received HTML, CSS, and JavaScript content.

Limitations of HTTP

• Statelessness: HTTP is stateless by default, meaning the server doesn't retain any information about the client. To overcome this, mechanisms like cookies and sessions are used to maintain state.
• Security: HTTP lacks encryption, making data transmitted via it susceptible to interception, viewing, or modification by third parties. Hence, for secure data exchange, the more secure HTTPS (which uses SSL/TLS encryption over HTTP) is widely adopted.
• Performance: Traditional HTTP/1.x protocols perform poorly in high-latency environments due to their sequential and blocking nature (despite the use of persistent connections). HTTP/2 improves performance by introducing header compression, server push, and multiplexing of requests and responses.
• Unrestricted Data Size: HTTP has no limits on the size of data transmitted in a single request/response, which may lead to performance issues when transferring large amounts of data.
• Redundant Header Information: In HTTP/1.x, some header information is repeatedly sent in each request, leading to some degree of network bandwidth waste, although optimizations have been made in HTTP/2.

Over time, HTTP continues to evolve to address its limitations and meet the demands of modern web applications.

Introduction to HTTPS (Hypertext Transfer Protocol Secure)

What is HTTPS?

HTTPS, or Hypertext Transfer Protocol Secure, is a network protocol used for secure communication. The design purpose of this protocol is to ensure that data transmitted between a user and a website server cannot be intercepted or tampered with by third parties. In other words, it provides security for data transmission over HTTP by encrypting it.

Comparison of HTTPS and HTTP Working Mechanisms

• HTTP (Hypertext Transfer Protocol): It is a transmission protocol used to transfer hypertext from a server to a local browser. HTTP sends data in plaintext, meaning requests and responses are unencrypted, making it vulnerable to interception or other security threats.
• HTTPS: HTTPS incorporates the SSL/TLS protocol on top of HTTP to establish an encrypted communication channel between the client and server. In this channel, data is encrypted before transmission and decrypted upon arrival, enhancing data privacy and security.

The specific process is as follows: when a user attempts to access a website via HTTPS, the user's browser first initiates a "handshake" process with the website server. During this process, the server provides its SSL certificate, which contains the server's public key. After verifying the certificate's validity and confirming that it belongs to the genuine website through a series of checks, the browser generates a symmetric encryption key and encrypts it using the server's public key, sending it to the server. Upon receiving it, the server decrypts it using its private key to obtain the symmetric encryption key. Subsequently, both parties use this symmetric key for encrypted communication.

Security Features Enhanced by HTTPS

The security features enhanced by HTTPS primarily include:

• Encryption: With the SSL/TLS protocol, HTTPS encrypts all communication content between the client and server, including URLs, form data, cookies, etc., making it unreadable to eavesdroppers.
• Data Integrity: Prevents data from being tampered with by third parties during transmission, ensuring that the received data matches what was sent.
• Authentication: SSL certificates are used to verify the server's identity, ensuring that the user is not accessing a fraudulent website. These certificates are typically issued by trusted Certificate Authorities (CAs) and can mitigate man-in-the-middle attacks.

In summary, HTTPS plays a crucial role in ensuring privacy and security during website interactions. With increasing awareness of cybersecurity, more and more websites are adopting the HTTPS protocol.

6 Differences Between HTTP and HTTPS

This table clearly illustrates the differences between HTTP and HTTPS in terms of security, encryption method, port number, URL identification, certificate, and performance.

Conclusion

Due to security reasons, modern websites and online services tend to use HTTPS. Ensuring the security of user data has become one of the primary tasks on the internet, making HTTPS increasingly the standard protocol. Especially for websites handling sensitive information (such as credit card details, login credentials), HTTPS is essential. Most browsers also indicate whether the current website connection is secure (i.e., using HTTPS) by displaying a lock icon in the address bar.

Reference Links：

• HTTP/1.1 Specification - The official specification for HTTP/1.1 from the Internet Engineering Task Force (IETF).
• Hypertext Transfer Protocol – HTTP/2 - The official specification for HTTP/2 from IETF.
• TLS (Transport Layer Security) Protocol - The official specification for TLS 1.3, which is used in HTTPS, from IETF.

The 6 Differences Between HTTP and HTTPS

HTTPS is the secure version of HTTP, which encrypts data transmission using the SSL/TLS protocol, ensuring the security and integrity of data during transmission, thus preventing interception or tampering of data.

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