This topic describes the benefits and usage notes of Hypertext Transfer Protocol Secure (HTTPS) secure acceleration and how it works. HTTPS secure acceleration encrypts HTTPS connections between clients and Alibaba Cloud Content Delivery Network (CDN) nodes. It ensures data security during transmission.

What is HTTPS?

Hypertext Transfer Protocol (HTTP) transmits data in plaintext and does not encrypt data in any form. As an extension of HTTP, HTTPS is an HTTP channel designed to ensure data security. In HTTPS, the communication protocol is encrypted by using Transport Layer Security (TLS) or Secure Sockets Layer (SSL). HTTPS supports authenticated and encrypted connections. Therefore, it is widely used to transmit sensitive data, such as transactions, over the Internet.

According to a report released by Electronic Frontier Foundation (EFF) in 2017, more than 50% of web traffic worldwide is transmitted over HTTPS.

How it works

After you enable HTTPS in the Alibaba Cloud CDN console, requests transmitted from clients to Alibaba Cloud CDN nodes are encrypted over HTTPS. CDN nodes retrieve requested resources from origin servers and then return the resources to clients based on the HTTPS settings of the origin servers. We recommend that you configure and enable HTTPS for your origin server to implement end-to-end HTTPS encryption.

The following figure shows how HTTPS works.Flowchart
  1. The client sends a request over HTTPS.
  2. The server has the public and private keys prepared.
    Note You can bring your own public or private keys, apply for them from a professional organization, or apply for a free certificate in the Alibaba Cloud CDN console.
  3. The server sends the public key to the client.
  4. The client authenticates the certificate.
    • If the certificate is valid, the client generates a random number as a key. The client uses the public key to encrypt the random number and transmits the random number to the server.
    • If the certificate is invalid and the SSL handshake fails, you must upload another certificate for authentication.
    A certificate is considered valid if the following conditions are met:
    • The certificate is not expired.
    • The certificate is issued by a trusted certificate authority (CA).
    • The public key of the certificate can decrypt the signature of the server certificate.
    • The domain name on the server certificate is the same as the actual domain name hosted on the server.
  5. The server uses the private key to decrypt the random number.
  6. The server uses the random number to encrypt data transmitted from the server.
  7. The client uses the random number to decrypt the received data.


Benefits of HTTPS secure acceleration
  • HTTPS secure acceleration prevents communications from eavesdropping, tampering, impersonation attacks, and man-in-the-middle (MITM) attacks.
  • HTTPS encrypts sensitive information such as session IDs and cookies before transmission. This minimizes the risk of sensitive information leaks.
  • HTTPS checks data integrity during transmission to protect the data from MITM attacks, such as DNS hijacking and tampering.
  • HTTPS is the new standard. An increasing number of mainstream browsers such as Google Chrome 70 and later and Mozilla Firefox have labeled HTTP web URLs as insecure since 2018. If you choose to use HTTP, your website may be exposed to security risks. Users who visit your website by using these browsers are prompted that this website is insecure. This compromises user experience and may reduce visits to the website.
  • Google and Baidu prioritize HTTPS web URLs in the search results. Additionally, mainstream browsers must support HTTPS before they can support HTTP/2. HTTPS is a more reliable choice in terms of security, market share, and user experience. Therefore, we recommend that you upgrade your communication protocol to HTTPS.


The following table describes the scenarios of HTTPS secure acceleration.
Scenario Benefit
Enterprise applications HTTPS protects confidential information on enterprise websites from being hijacked or intercepted. Confidential information, such as customer relationship management (CRM) data and enterprise resource planning (ERP) data, can be protected during transmission.
Government websites HTTPS protects sensitive information on government websites against attacks such as phishing and hijacking. Leaks of such information may compromise the public trust.
Payment systems HTTPS protects sensitive data such as customer names and phone numbers used in payment transactions against hijacking and spoofing. If sensitive data is leaked, attackers can use such data for fraudulent activities. This causes losses to both the customer and the enterprise.
API operations API operations can use HTTPS to encrypt important information, such as sensitive data and important instructions. This protects the information against hijacking.
Enterprise websites HTTPS improves user trust and experience. Web browsers display a lock icon in the address bar for websites with domain validated (DV) or organization validated (OV) certificates. The enterprise name is displayed together with the lock icon for websites that include extended validated (EV) certificates.

Usage notes

The following table describes the usage notes of HTTPS secure acceleration.
Category Usage note
  • The following scenarios support HTTPS secure acceleration:
    • Image and small file distribution

      Web portals, e-commerce websites, news websites and applications, government websites, enterprise websites, entertainment websites and applications, and gaming websites and applications.

    • Downloads of large files

      Applications and websites that provide downloads of video and audio files.

    • ApsaraVideo for VOD

      Websites and applications that provide audio and video content such as movies, online education, news, and social media.

  • You can enable HTTPS for wildcard domains.
  • You can enable or disable HTTPS secure acceleration as needed.
    • When HTTPS secure acceleration is enabled, you can modify certificates. The system supports HTTP and HTTPS requests by default. You can also Enable force redirect to customize request methods.
    • When HTTPS secure acceleration is disabled, the system no longer supports HTTPS requests or keeps certificate or private key information. When you enable HTTPS again, you must upload a certificate or private key again. For more information, see Configure an SSL certificate.
  • You can view certificates. You cannot view private keys because they are sensitive information Keep certificate-related information confidential.
  • You can renew a certificate. However, proceed with caution. After a certificate is renewed, it takes effect within one minute.
HTTPS secure acceleration is a value-added service. After you enable HTTPS, you are charged based on the number of HTTPS requests. For more information, see Static HTTPS requests.
Note HTTPS requests are billed separately and the fees cannot be offset by data transfer plans of Alibaba Cloud CDN. Before you enable HTTPS secure acceleration, make sure that you have a sufficient balance in your account. Your CDN service may be suspended when the balance is insufficient.
  • You must upload certificates and private keys in the PEM format for domain names for which HTTPS secure acceleration is enabled.
    Note The Tengine web server used by Alibaba Cloud CDN is designed based on the NGINX web server architecture. Therefore, the web server supports only certificate files in the NGINX-compatible PEM format. For more information, see Overview of certificate formats.
  • The uploaded certificate must match the private key. Otherwise, requests sent from clients fail to pass the authentication.
  • A private key cannot carry a password.
  • Only SSL and TLS handshakes that include Server Name Indication (SNI) values are supported.

Related features

You can enable the following features as needed to enhance data security.
Feature Description
Configure an SSL certificate Implements HTTPS secure acceleration.
Enable HTTP/2 Enables the latest HTTP protocol, HTTP/2. HTTP/2 is supported by mainstream browsers such as Google Chrome, Internet Explorer 11, Safari, and Mozilla Firefox.
Enable force redirect Redirects requests to HTTP or HTTPS requests by force.
Configure TLS Ensures communication security and data integrity.
Configure HSTS Forces clients such as browsers to communicate with servers over HTTPS. This reduces the risk of cookie hijacking.