The digital market is increasing rapidly, with more people staying online than offline. Online marketing, shopping, gaming, making transactions, viewing news/sports, etc., have increased tremendously.
You may have encountered times when sites slow down or hang up as an internet user. This usually happens due to heavy network traffic. However, another reason for poor site performance may be the SSL/TLS certificate installed for site security.
Since this security solution is essential and cannot be removed, you can only try to enhance the server speed with SSL Offloading.
This topic is alien to many not from IT/technical backgrounds; hence, in this article, we will discuss SSL Offloading, its need, its functioning, and its pros and cons.
What is SSL Offloading?
SSL Offloading is the best and ideal solution for companies that crave site performance and security. In short, SSL offloading helps enhance site performance without affecting site security.
It balances the extra load of SSL/TLS functions like encryption/decryption and the SSL handshake process by using separate ASIC (Application-Specific Integrated Circuit) processors. This, in turn, emancipates the processing power for the respective website/application. This process is also termed load balancing. The main motto of load balancers is to distribute workloads evenly across varied resources.
How Does SSL Offloading Work?
To separate the functioning of the SSL security certificate, SSL offloading devices are used, which help to free the server by alleviating the processes of encryption and decryption. This is done using a different SSL proxy device stationed between the server and the browser.
ASIC processor, as stated above, is that SSL offloading device that functions as a load balancer (proxy server). These processors are designed in such a way that they secure the SSL protocol and it is functioning, thus lessening the burden on the servers.
In SSL offloading, the client sends the encrypted data to the load balancer, which decrypts the information and sends the plain text to the server.
This offloading device also inspects the network traffic by blocking suspicious traffic before sending any data to the server.
Some top-load balancers are Kemp LoadMaster, Citrix ADC, Nginx, etc.
How a Regular SSL Connection Is Made Without SSL Offloading:
Now that you know and have gained knowledge about the importance and functionality of the different types of SSL offloading, it’s time to discover the functioning of the SSL certificate.
How does an SSL Certificate work?
An SSL/TLS certificate process offers insight into how an SSL certificate works once you install it on the server.
- When a user visits a website from their browser (client), the browser executes an SSL handshake process to establish a secured HTTPS (hypertext transfer protocol secure) connection.
- An encrypted session key is created using the public key and is later sent to the server.
- The server decrypts this session key with the site’s private key.
- The private/public key pair is unique for all sites. This key pair is mathematically linked with cryptographic algorithms.
- Thus, the data encrypted with the public key can only be decrypted with the corresponding private key.
- A common key, the session key, serves both the purposes of encryption and decryption of data exchanged between the browser and the server.
Why Need SSL Offloading?
As stated above, the public and private keys are used in the encryption/decryption process. Their key length is 2048-bit long with the RSA algorithm. Though it secures the web with its robust encryption, it is very heavy and makes encryption and decryption quite slow.
Hence, the session key is generated, which provides 256-bit encryption and is quicker than the public and private keys.
Another issue that needs to be addressed is to decrease the burden of multiple requests received by the server. When many users try to access a website simultaneously, the server needs to attend to varied session keys and encryption/decryption requests. This process increases the burden on the server, thus influencing its functioning and making it slow.
To curtail this burden from the server and to enhance the smooth functioning of its backend functions, SSL offloading process and devices were introduced.
To understand the need for SSL offloading, we first need to understand what SSL/TLS encryption is:
SSL/TLS is mainly used to provide an advanced level of security between websites and servers.
Without SSL encryption, chances are hackers will perform MIM attacks against the network, and if they’re successful, you would lose a lot of sensitive information such as cookies or other authentication data.
So, with SSL offloading, you can rest assured that the entire network is deemed secure, as well as packets that pass from the client and server are encrypted.
Types of SSL Offloading:
As stated above, the SSL offloading process is carried out by using a load balancer stationed between the browser and the server. This load balancer device takes care of all the encryption/decryption tasks. This device uses the server’s SSL certificate and private key to carry out the task.
The load balancer can carry out the two types of SSL offloading processes. They are:
- SSL Termination
- SSL Bridging
Let us explore these methods and discuss their pros and cons to understand them better.
SSL termination is the process of decrypting encrypted traffic before transferring it to a web server. Many web pages are already encrypted with the SSL protocol and its more advanced replacement TLS..
The SSL Termination method of SSL offloading helps in hastening the server speed. This method connects the browser with the load balancer via HTTPS (encrypted connection). Later the load balancer is connected to the server via HTTP (unsecured connection).
This means the connection between the browser and the load balancer is encrypted and secure. In contrast, the connection between the load balancer and the server is unencrypted and unsecured.
- The load balancer is connected to both parties, i.e., the server and the user’s browser.
- When the user requests a secured (HTTPS) connection, a session key is generated using the server’s public and private keys. This session key is used between the load balancer and the browser to establish encrypted communication.
- The browser’s encrypted data is passed to the load balancer, which decrypts the data using the session key and later passes the decrypted data to the server.
Since the server receives the data in plain format, it sends its response to the load balancer in the same format (decrypted format).
- The load balancer uses the session key to encrypt this data again and sends it to the browser, which later decrypts it using the same session key.
- Since the server is relieved from the burden of encrypting/decrypting the data, its workload is reduced, and speed is enhanced.
- This process is ideal for sites that do not deal with sensitive stuff like blogs, informative sites, etc.
- The data exchanged between the load balancer and the server is in plain format (unencrypted); hence, it is easily vulnerable to MIM (man-in-middle) attacks and data theft.
- This affects the main motto of the SSL certificate, which is to ensure data confidentiality. Since the entire process is not secured, data privacy is at risk.
The server with the load balancer shares the private key for data decryption. This makes it vulnerable to cyber-attacks.
- Clients are betrayed since they are ensured of data encryption, but they are unaware that encryption security is just mid-way and does not cover the entire process.
- Since the load balancer is a third-party device that handles the data, ensuring data secrecy is difficult.
SSL bridging is another method of SSL offloading. SSL bridging is ideal for sites that store and deal with sensitive data, i.e., banking sites, financial institutions, healthcare sites, etc. Sites handling sensitive data cannot use SSL termination since it is a risky SSL offloading process.
HTTPS sites need to handle a lot of traffic from the users, which hampers the servers’ functioning since these servers need to block malicious traffic and other intrusions before passing the data. In such cases, SSL Bridging comes to the rescue.
Like SSL termination, this method also involves a load balancer between the browser and the server. Only the functioning of this method is slightly different from the SSL termination method.
- The user’s browser sends encrypted data to the load balancer via an HTTPS connection.
- The load balancer decrypts the data and carries out an SSL inspection.
- This SSL inspection is done to catch malicious traffic and block it.
- After the inspection, the load balancer encrypts the decrypted data and sends it to the server later. Thus, the data remains secure during the entire process.
- Later, the server carries out the encryption/decryption process.
Hence, in the SSL bridging method, the main motto of the load balancer is to block malicious content proceeding from the client.
- The main benefit of this method is that the data is secured during the entire browser-server conversation since it is always exchanged in an encrypted format.
- This method helps prevent malicious attacks like MIM, DDoS (distributed denial of services), malware, etc.
- Since the server carries out the encryption/decryption functions, the workload is still the same; hence, the burden on the server is not reduced.
- The re-writing process of SSL bridging is a major con. The load balancer is authorized to inspect and edit browser data if it is AI (Artificial Intelligence) finds it suspicious.
It later re-writes and re-encrypts safe content and passes it to the server. Any malfunctioning by the AI may cause the load balancer to block sensitive stuff too, which may be missed out on being transferred.
Benefits of SSL Offloading:
SSL offloading offers many benefits and is handled by a third-party security device. Here are a few advantages to SSL offloading:
- SSL offloading makes sure that websites and software are protected. It secures them against cyberattacks like DDoS and man-in-the-middle.
- Prevent server overload and downtime.
- Hasten the SSL connection and improve performance.
- It offloads the encryption/decryption process from the servers, thus reducing their burden and helping them to focus on their main functions.
- It helps in saving server resources.
- If the SSL bridging load balancer is used, it may help block malicious traffic, SSL inspection, HTTPS traffic inspection, etc. This helps in detecting attackers hiding in HTTPS traffic and blocking them.
- It enhances the page load speed, thus raising site visibility in SEO (search engine optimization).
- The server response time is minimized, and its performance is enhanced.
- The website stability and speed are improved.
SSL offloading reduce server’s burden and optimize server resources. SSL offloading saves page-loading time. If you want to buy an SSL certificate then, you can find low-priced or Cheap SSL certificates available with varied SSL certificate providers, which can help secure your web with encryption. However, apart from site security, site speed is also essential.
If your site load time is more than 2-3 seconds, it may increase your bounce rate since visitors are likely to abandon such sites. SSL offloading helps speed up your server and ensures a good position against competitors.
Since you now have a fair idea about SSL offloading techniques and their pros and cons, you can select any offloading techniques ideal for your business.
As far as the load balancer providers are concerned, select them wisely since you need to trust them with your server’s private key and site-sensitive data.
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