Here’s Everything You Need To Know About TLS
What is TLS?
In computer security, TLS (Transport Layer Security) is a protocol that encrypts communication between a client and server. HTTP uses only this security protocol. This is what the S stands for by the way.
It is the most widely used security protocol today and is best suited for web browsers and other applications that require secure data exchange over a network. These include web browsing sessions, file transfers, virtual private network (VPN) connections, remote desktop sessions, and voice over IP (VoIP).
More recently, TLS has been integrated into modern cellular transport technologies, including 5G, to protect core network functions across the entire Radio Access Network (RAN).
How does TLS work?
TLS uses a client-server handshake mechanism to establish a secure, encrypted connection and authenticity of the communication. Here is a detail of the process:
- Communication devices exchange cryptographic functions
- An authentication process using digital certificates is performed to prove that the server is the entity it claims to be.
- A session key exchange takes place. During this process, the clients and server must agree on a key to establishing that the secure session is really between the client and the server and not between an attempt to hijack the conversation.
TLS uses a public key exchange process to establish a shared secret between communicating devices. The two methods of the handshake are the Rivest-Shamir-Adleman (RSA) handshake and the Diffie-Hellman handshake.
Both methods lead to the same goal of establishing a shared secret between communication devices so that communication cannot be diverted. Once the keys are exchanged, data transfers between devices in the encrypted session can begin.
The history and evolution of TLS
TLS originated from Netscape Communications Corp’s Secure Sockets Layer protocol and has largely replaced it, although the terms SSL or SSL/TLS are sometimes still used interchangeably. The IEFT officially adopted the SSL protocol to standardize it with an open process and released version 3.1 of SSL in 1999 as TLS 1.0.
The protocol was renamed TLS to avoid legal issues with Netscape, which developed the SSL protocol as a core part of its original. Depending on the protocol specification, TLS is composed of two levels: the recorded TLS protocol and the TLS protocol of the hand handle.
The record protocol provides connection security, while the handshake protocol allows the server and client to authenticate each other and negotiate encryption and key encryption algorithms before data exchange.
The latest version of TLS 1.3 was officially finalized by the IETF in 2018. The main advantage over previous versions of the protocol is that encryption mechanisms are added when establishing a connection handshake between a client and a server.
Although previous versions of TLS also offer encryption, TLS manages to establish an encrypted session earlier in the handshake process. it also reduces the number of steps required to complete a handshake, greatly reducing the time required to complete a handshake and begin transmitting or receiving data between client and server.
Another improvement of TLS 1.3 is that several cryptographic algorithms used to encrypt data have been removed because they are considered obsolete and not recommended for secure transport. Additionally, some optional security features are now required. Hashing is no longer supported, Perfect Forward Secrecy (PFS) is required, and Rivest Cipher 4 (RC4) negotiation is prohibited. This eliminates the possibility of a session with an unsecured encryption algorithm, or a method known in the TLS 1.3 version.
The Benefits of Transport Layer Security
Like the SSL protocol, TLS ensures secure communication. With TLS, authentication and message exchanging are more secure because it uses features such as:
- To ensure the integrity of a record during transmission over an open network such as the Internet, SSL uses keyed message authentication, but TLS uses the more secure Key-Hashing for Message Authentication Code (HMAC).
- Enhanced Pseudorandom Functions (PRF) are key generation algorithms used with the HMAC in TLS. Using two algorithms increases security by preventing the data from being altered if only one algorithm is compromised. If both algorithms remain secure, the data cannot be altered.
- TLS includes PRF and HMAC values in the message to verify that the exchanged messages were not tampered with, while SSL and TLS use public-key cryptography to authenticate exchanged messages.
- To ensure maximum consistency, the TLS protocol specifies the type of certificate to be exchanged between nodes.
- When certain alerts are sent, TLS provides more specific alerts.