How to optimize SSL handshake? A guide to performance improvement methods and practices

at the moment when HTTPS has become the standard of websites, SSL handshake is the pre-link of encrypted communication, and its performance directly affects the loading speed and user experience of websites. Although many websites have deployed SSL certificates, they ignore SSL handshake optimization, resulting in high first visit latency and increased user churn rate. This article will deeply analyze the performance bottleneck of SSL handshake, and share the performance improvement methods of SSL handshake that can be landed from multiple dimensions such as protocol optimization, server configuration, and caching strategy, providing comprehensive practical reference for website operation and maintenance personnel.

What are the SSL handshake performance bottlenecks?

to optimize the SSL handshake, you first need to identify the core source of its performance bottleneck in order to develop a targeted solution.

1, multi-round communication interaction delay

traditional SSL handshake requires the client side to complete at least 3 TCP handshakes with the server, and then 2-3 rounds of encryption negotiation, the whole process takes hundreds of milliseconds, if the user is in a cross-regional network environment, the delay will increase exponentially, directly lowering the first screen loading speed.

2, encryption algorithm computational overhead

SSL handshake process, both parties need to complete key exchange, certificate verification and other encryption calculations, especially asymmetric encryption algorithms such as RSA, which consume a lot of server CPU resources.

How to achieve SSL handshake session reuse?

session reuse is one of the most effective ways to reduce SSL handshake latency and avoid repeating the entire cryptographic negotiation process.

1, session identifier reuse

after the first SSL handshake is completed, the server will generate a unique session identifier and send it to the client side, the client side carries the identifier for subsequent access, and the server can directly reuse the previous session parameters after verification, without re-performing key exchange and certificate verification, SSL handshake time can be compressed to about 1/3 of the original.

2, session ticket multiplexing

different from the session identifier, the session ticket is encrypted by the server and sent to the client side for storage. When the client side visits again, the ticket is submitted directly, and the server can restore the session state after decryption. This method does not require the server to store session information, and is more suitable for distributed server clustering scenarios. It can greatly reduce the storage pressure and management costs of the server.

How to upgrade the SSL handshake protocol version?

upgrade the protocol version on which the SSL handshake depends is a key move to improve performance from the bottom up, while also enhancing communication security.

1, enable TLS 1.3 protocol

TLS 1.3 protocol greatly simplifies the SSL handshake process, merges multiple rounds of interaction into 1-RTT or even 0-RTT handshake, cancels unnecessary encryption negotiation steps, and adopts a more efficient ECC elliptic curve encryption algorithm. Under the premise of ensuring security, the SSL handshake delay is reduced by more than 50%. At present, mainstream browsers and servers have supported this protocol.

2 Disable old protocol versions

disable the old protocol versions such as TLS 1.0 and TLS 1.1 in time, not only to avoid the compatibility overhead during the SSL handshake process, but also to eliminate the security bugs existing in the old protocol. The operation and maintenance personnel can keep only TLS 1.2 and TLS 1.3 versions through the server configuration, while taking into account the compatibility and security, improve the overall efficiency of the SSL handshake.

What are the server-side optimization of SSL handshake?

in addition to protocol and process optimization, server-side configuration adjustment can also effectively improve the processing efficiency of SSL handshake.

1 Configure the session cache pool

configure a sufficient capacity of SSL handshake session cache pool on the server side, set the cache expiration time reasonably, and ensure that most of the repeated access clients can hit the cache to reduce the number of repeated handshakes. At the same time, the cache pool size can be dynamically adjusted according to the server performance and concurrency to avoid the waste of resources caused by cache overflow.

2, using hardware acceleration equipment

for highly concurrent e-commerce and financial websites, SSL hardware acceleration cards can be deployed to offload the encrypted computing tasks in the SSL handshake process to hardware devices to reduce the server CPU load. Hardware acceleration devices can multiply the processing capacity enhancement of SSL handshake and effectively cope with the performance pressure under peak traffic.

To sum up, SSL handshake optimization is the core link of taking into account the security and performance of the website. By clarifying the performance bottleneck, realizing session reuse, upgrading the protocol version, optimizing the server configuration and other means, the SSL handshake delay can be effectively reduced and the website loading speed can be improved. The operation and maintenance personnel need to combine the business scenarios of their own website with the client base, choose the appropriate optimization scheme, and bring a smoother access experience to users under the premise of ensuring the security of encrypted communication.