SSL Offloading: Definition, Benefits, & How it Works

December 12, 2022

IT teams often face the conundrum of prioritizing either security or performance. Unfortunately, when security takes precedence, performance usually takes the backseat. This doesn’t sound good for any thriving business, right? 

Take SSL certificates, for example. A secure socket layer (SSL) is a cryptographic protocol. It protects data as it travels from the client’s browser to the servers. Although SSL is an excellent solution to encrypt and safeguard data, it can cause latency. This is because when a client sends a request to the server, it has to decrypt the information, check for any anomalies, re-encrypt it, and respond to the client. And because SSL decryption and re-encryption is a compute-intensive task, the servers can slow down as the traffic spikes.

So how can IT teams enhance website and application performance while ensuring data integrity? By deploying SSL offloading. Let’s explore more about it.

What is SSL Offloading?

To understand SSL offloading, let’s first comprehend how SSL connection works:

  1. When a client requests access to any web application/website with a valid SSL certificate, the browser and web server initiate an SSL handshake.
  2. In the handshake process, the browser looks if the server is using a legitimate SSL certificate issued by a trusted third party.
  3. Then public and private keys are used to encrypt and decrypt the information and ensure secure communication.
  4. Once the above steps are completed, a third key, called the session key, is created.
  5. Now that the server and browser have established a secure connection, safeguarded communication can take place.

So, where does SSL offloading come into the picture?

SSL certificates use cryptographic keys for the task of decryption and encryption. A few years back, one of the most common cryptographic keys used was RSA. They had increasing key lengths like 1024 bits, or 2048 bits. However, more efficient cryptographic keys are ECC (elliptic curve cryptography).  

While ECC is an efficient SSL offloading method, it’s still a compute-intensive task. So when a server is tasked with this activity, it becomes sluggish.

That’s where SSL offloading comes into play. 

SSL offloading relieves the server burden by terminating the encryption-decryption task to a dedicated security appliance. This appliance is usually an ADC (application delivery controller). It’s placed between the client’s browser and the server. This ADC will receive client requests, decrypt the traffic and finally, send it to the server.

SSL offloading is necessary for businesses like banks, eCommerce, healthcare institutes, or SaaS. They handle a massive amount of concurrent traffic and have to ensure the integrity of their client’s data.

How Does SSL Offloading Work?  

SSL offloading happens in one of the two ways:

  1. SSL Termination

First, the client request reaches the ADC in a secured HTTPS format. Then, the ADCs check if the traffic is legitimate and is not a hacker disguised as a genuine client. 

The data is then transmitted through HTTP or plain text to the server. The encryption gets removed, leaving the server with the task of reviewing requests and providing responses.

Despite being in plain text, the transmission cannot be exploited by hackers because HTTP communication takes place within a firewall-protected framework. However, this method is not recommended for businesses that handle sensitive customer information like social security numbers, addresses, and banking details.

The primary purpose of this method is to accelerate server speed.

  1. SSL Bridging 

The initial process of SSL bridging is similar to that of termination. First, the client request meets ADC in a secured HTTPS format. Then, ADC decrypts the data, and analyzes the packet content for load balancing, any malware or anomalies. Next, the SSL bridging method re-encrypts the data before sending it to the server. 

The server decrypts the information, responds to the client query, and re-encrypts it before sending it to the ADC. 

In this method, the information remains secure throughout the process. It’s helpful for businesses dealing with sensitive client information.

Lastly, both the methods mentioned above aim to serve a single goal: to relieve the servers off their existing burden. It enhances the performance of web apps without compromising information security.

Benefits of SSL Offloading

SSL offloading is handled by a third-party security device. It not only ensures accelerating SSL but also enhances performance. Here are a few benefits of SSL offloading:

  • Ensures that websites and applications are secured. It protects them against internet-based threats like DDoS and man-in-the-middle.
  • Maintains server health by balancing load among various servers. So, when the traffic spikes, servers don’t get overwhelmed and exhausted. This also ensures scalability.
  • Maintains high availability by preventing server overload and downtime.
  • Accelerates SSL connection and boosts performance. 

Array Networks SSL Intercept

Array Networks provides industry-leading third-party security devices. It enables IT teams to gain visibility into blind spots created by SSL encryption. This device helps relieve the server’s stress and serves as a load balancer, ensuring high performance and availability.

Our SSL intercept comes with multiple deployment options and can be centrally managed.

To know more about our SSL intercept, contact our sales team today!

Shibu Paul

Mr. Paul has 25 years of experience in the field of Digital transformation – IT, IS and telecom – having worked with Sify Ltd, British Telecom Global services (India) and BT Americas in various roles. He was part of the team that launched the first IP network, first private ISP and first Certifying Authority in India. He joined Array in 2009 as country sales head and progressed to leadership positions including Country Manager and Regional Director-APAC.