Shulou(Shulou.com)06/02 Report--

HTTPS protocol is HTTP+SSL/TLS, which adds SSL/TLS layer on the basis of HTTP, which provides three functions: content encryption, identity authentication and data integrity. The purpose is to encrypt data for secure data transmission.

HTTPS increases the security of data transmission through three major functions, but it also brings new challenges to the performance optimization of Web.

HTTPS slows down user access speed (requires multiple handshakes)

After the website was switched to HTTPS, the jump from HTTP to HTTPS increased the time-consuming for users to visit (most websites use 301,302 hops)

The security algorithms involved in HTTPS consume CPU resources and require additional server resources (https access process requires encryption and decryption)

Analysis of HTTP Jump to HTTPS interaction process

1. After the user typed http://www.domain.com/1213.gif in the browser and clicked enter, the browser shook hands with the server three times.

two。 The server receives the user's request and responds to the 301 status code. The server asks the user to jump to HTTPS and request https://www.domain.com/1213.gif again.

3. The user re-initiates the HTTPS request and makes three TCP handshakes with the server again.

4. After the TCP handshake is successful, the browser starts the TLS handshake with the server. HSTS redirection technology

Tencent Cloud uses HSTS (HTTP Strict Transport Security) technology. When HSTS is enabled, the browser will always connect to the HTTPS encrypted version of the website.

1. When users enter the HTTP protocol in the browser to access, the browser will automatically convert HTTP to HTTPS for access, to ensure that the user access security; 2. Save the appearance of 301 jump, shorten the visit time; 3. Can prevent SSL Strip-based middleman * *, in case there is an error in the certificate, the error will be displayed, and the user can not avoid warnings, so that the access of users can be more effectively and securely guaranteed. TLS handshake optimization

Before transmitting the application data, the client must negotiate the key, encryption algorithm and other information with the server, and the server must send its own certificate to the client to show its identity. These links constitute the TLS handshake process.

TLS False Start function

Another cloud uses False Start (preemptive start) technology. Before completing the TLS handshake with the server, the browser begins to send request data. After receiving these data, the server completes the TLS handshake and begins to send response data.

After the False Start function is enabled, the data transmission time will be further shortened.

Session Identifier (session Identifier) reuse

If a user's business request contains multiple encrypted streams, the client and the server will shake hands repeatedly, which will inevitably lead to more time loss. Or some special circumstances lead to a sudden interruption of the conversation, the two sides need to shake hands again, increasing the user access time.

Therefore, Paiyun provides Session Identifier (session Identifier) reuse function.

(1) the server generates and records an ID number for each session, and then sends it to the client. (2) if the client initiates a reconnection, just send the ID number to the server. (3) the server receives the ID number sent by the client, and then looks up its own session record. after matching the ID, both parties can re-use the previous symmetric encryption key for encrypted data transmission without having to regenerate and reduce the interaction time.

Therefore, it can further reduce the access time of the client and improve the access experience of users. This feature is enabled by default at Zaiyun. No special configuration is required. The package capture is shown below:

Turn on OSCP Stapling to improve the efficiency of TLS handshake

Adopt OCSP Stapling to improve the performance of HTTPS. The server takes the initiative to obtain the OCSP query result and sends it to the client along with the certificate, so that the client can directly verify the certificate through Web Server and improve the efficiency of TLS handshake.

The CVM simulates the browser to initiate a request to the CA, saves the OCSP response with the signature of the CA organization locally, and then sends the OCSP response to the browser during the handshake with the client, eliminating the browser's online verification process. Since browsers do not need to query the certificate status directly from the CA site, this feature has a significant improvement in access speed.

Fully forward encrypt PFS to protect user data and prevent private key disclosure

The asymmetric encryption algorithm RSA contains a public key and a private key, in which the private key is confidential and not public. Because this algorithm can be used for both encryption and signature, it has a wide range of uses, but it will still encounter some problems:

(1) if I am a *, although I do not know the private key now, I can save all the previously transmitted data (encrypted) between the client and the server (2) if one day, the server maintainer accidentally leaked the private key, or the server was hacked and obtained the private key (3) then I can use this private key to crack the data that has been saved by me. Get useful information from it

So in order to prevent the above phenomenon, we must protect our private key.

But if the private key is indeed leaked, how can we fix it? That requires PFS (perfect forward secrecy) full forward secrecy, which is used for the exchange of symmetric keys between the client and the server, which plays the role of forward secrecy, that is, even if the private key is disclosed, * cannot crack previously encrypted data.

To achieve this feature, the server needs to support the following algorithms and signature combinations:

(1) ECDHE key exchange, RSA signature, (2) ECDHE key exchange, ECDSA signature

Zaipaiyun supports the above combinations by default without special configuration. The package capture is shown in the following figure:

HTTP/2 protocol support

HTTP/2 is implemented on the basis of the HTTPS protocol, so as long as you use the domain name of the cloud HTTPS acceleration service, you can enjoy the HTTP/2 service for free without any special configuration. The whole platform supports enabling HTTP/2.0 by default, which is seamlessly compatible with browsers and servers.

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