The Importance of Transport Layer Security Protocol

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The internet has been around for quite some time now. More and more people are getting used to using the internet. In the early days of the internet, people used it for specific purposes and went on with their lives. Now, our whole lives revolve around the internet. Businesses work out of virtual offices, office meetings are held over the internet and social media profiles speak louder for people than they themselves. However, web security concerns have also been around for as long as the internet has. How do you know the website you shopped at won’t use your card details to empty your account? Who has access to your data? Is anyone keeping an eye on the internet?

Well, no-one is literally keeping an eye on the internet, but there are systems in place to make sure that communications happen quickly, effectively and securely. There are also protocols set by the Secure Data Network Security System to ensure this. Read more to know the process and technicalities such as the individual protocol details in addition to information such as which type of address is used at the transport layer to identify the receiving application?

How is a secure transaction ensured?

The transfer of data over the internet involves four steps or layers which function based on four different protocols.

Application layer

  • At the application layer, the data to be sent is converted into a particular format using a protocol that will make it readable at the destination. For example, data converted using HTTP protocol is readable on web servers.
  • Encryption of the data happens at the application layer using the TLS/SSL protocol.

Secure Sockets Layer (SSL) protocol and the later version Transport Layer Security (TLS) protocol are cryptographic protocols which play a huge role in ensuring that the data you send via the Internet is encrypted and authenticated. SSL was deprecated in 1993, followed by two initial versions of TLS and ultimately we have the current TLS 1.3.

What is the role of TLS/SSL?

TLS/SSL is responsible for encrypting the data that is being transferred in a way that only the receiver web server is able to decode it. This way, even if some data gets misdirected or intercepted during transit, the interceptor will not be able to access the data in any consequential manner.

How does TLS work?

  • When a website installs a TLS certificate after registering with the certificate authority, it gets a public key which can be accessed by anyone who visits the website, to verify its identity.
  • For a transaction of any kind to happen, a connection is established through a process called TLS handshake.
  • Through the process, the client and the webserver agree on the encryption code, the format of encryption, decryption algorithm etc. are agreed upon during the TLS handshake. Additionally, the website is also verified for authentication during this handshake.

Once the data is encrypted, the encrypted application is sent to the transport layer.

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Transport layer

The transport layer designates the source and destination port numbers and facilitates the TCP session. It is important to know the details of the transport layer, such as ‘which type of address is used at the transport layer to identify the receiving application?’ In order to fully appreciate the efficiency of the security protocols.

  • The TCP/IP is in charge of determining how to establish communication between two systems over the internet, segment the message, send it to the right target and finally, how to reassemble the segments to recover the original message.
  • Which type of address is used at the transport layer to identify the receiving application? The port number. The port number through which the application is sent, is typically determined arbitrarily, but port numbers can also be specified for security reasons.
  • In order to establish a connection with the receiving server, the data to be transferred is converted according to HTTP. Before sending the data, the sender/client establishes a connection with the receiving web server based on TCP/IP Protocol through a three-step process of mutual agreement and acknowledgment between the two servers.  The three steps of mutual agreement between the sender/client and the receiver server that take place before sending the data are called the TCP handshakes.
  • The handshakes happen in a series of packets back and forth. First, SYN packet is sent by the source, called an “initial request” responding to which the target sends a SYN-ACK packet, which indicates readiness for the transaction. This is followed by the last step in the 3-step handshake, where the source sends an ACK packet, confirming the transaction about to happen.
  • The Internet Protocol (IP) is not a connected protocol, unlike TCP. This means that each of the segments are individually addressed to the target and sent separately. A connectionless protocol also doesn’t procure an acknowledgement by the receiver. The segments are received in scrambled order, possibly at different speeds. The TCP assembles the segments in the right order to recover the message at the receiver’s end. TCP also ensures that none of the segments are lost in transit. Being a connected protocol, TCP maintains the channel of communication right from sending the first request until the last segment is sent.

Internet layer/Network layer

At the internet layer, the TCP facilitated data is designated with the IP addresses of the sender and the receiver. Once the source and destination IP addresses are assigned, the packaged data is suitable for being transported to the physical hardware of the sender, called the link layer. At the internet/network layer, the IP address is used to identify the receiving application and the source as opposed to the port number the type of address used at the transport layer to identify the receiving application.

Link Layer

At the link layer, the data package is labelled with the unique hardware addresses i.e., the MAC addresses of the sender and the receiver, along with a protocol for data transmission. From there, the data package is travels from a transmission equipment, such as a Wi-Fi router through the internet, to the receiver server.

Once the receiving hardware gets hold of the data layered multiple times, it is unraveled layer by layer according to the specifications of the protocol at each layer to make sure that the original data is reassembled in the right order.

How can you make sure your data is safe on the internet?

  • Before you make any personal or financial transaction on a website, check whether the website has an ‘https’ at the beginning of its URL. HTTPS (Hypertext Transfer Protocol Secure) is an encrypted and authenticated transfer protocol that guarantees integrity unlike the HTTP.

Encrypted: The data you send over this website is impossible for any unauthorized person who manages to tamper with it during transit, to understand.

Authenticated: The website you are accessing has been authorized by a certificate authority. The certificate issued to the website comes with a public key that your browser can access to ensure that the website is secure and legitimate.

Integrity: The transactions that happen on this website are not tampered by any unauthorized entity during transit.

  • The websites that do not have an SSL certificate are usually flagged by most browsers as unsafe and search results that redirect to those websites are given low priority on search engines such as Google.
  • A padlock symbol at the left end of the URL box is also an indication that the website is secure. Some browsers, such as Firefox, indicates an unsecured website by a slash on the padlock.
  • Most browsers these days show messages on the screen that indicates a potential safety issue if you are about to divulge your information on an unsecured website.

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