What is SSL/TLS Handshake?

Last Updated : 12 Aug, 2024

The network is important for office, home, and business networks. The problem is at the utmost places wireless communication is used or we can say the wireless network is used which is effortlessly hackable and the router can be freely exploited if not secured rightly. So there's a need for security in the network. To fulfill this need we can use security protocols or cryptographic protocols to deliver authentication and data security.

What is Secure Socket Layer(SSL)?

It provides protection to the data that are aligned between the web browser and server. SSL encrypts the link between a web server and a browser which ensures that all data passed between them stay private and separate from attack.

Secure Socket Layer Protocols:

SSL record protocol
Handshake protocol
Change-cipher spec protocol
Alert protocol

Transport Layer Securities (TLS)

Transport Layer Securities (TLS) are aimed to give security at the transport layer. TLS was concluded from a security protocol called Secure Socket Layer (SSL). TLS ensures that no third affair may overhear or tampers with any communication.

When Does a TLS Handshake Occur?

In the startup of a protected relationship between a customer (such as an internet browser) and an expert organization (like a website), there is a TLS handshake. A secret exchange of greetings is like a handshake between two people, but in this case, it is where they agree on what information they want to keep safe before sharing anything. This process involves agreeing on ECMs through which they will communicate safely through the division of pairs while confirming identity integrity Through the use of encryption keys. The action of ensuring privacy besides safety measures for information being conveyed is also very significant.

What Happens During a TLS Handshake?

A secure connection is established by the client and server during TLS handshake. Here are the main steps :

ClientHello : This is where the client begins its handshake with a "hello" message sent to a server which includes supported encryption methods as well as other parameters.

ServerHello : In response, the server also sends its own hello message selecting an encryption method before sending over its digital certificate for authentication.

Key Exchange : In this step, both client and server agree on a shared symmetric key that will be used for client data encryption/decryption during their session. It may involve Diffie-Hellman key exchange or other ways.

Authentication : To prove its identity, the server presents a digital certificate. Then, it is up to the client to verify if such certificate is from a trusted source.

Session Key Generation : Both sides are able to use these exchanged keys in order to generate session keys that will be used for encryption/decryption of data while they are in session.

Finished : To confirm that the handshake went through successfully and that encryption is properly established both parties send 'finished' message.

After finishing these steps, they create secure connection which allows safe transfer of information between client and server at all times.

What is the difference between SSL and TLS protocols?

There are always security issues between client and host so Secure Socket Layer and Transport Layer Security are the cryptographic protocols used to provide authentication and data security between the web browser and web server and it encrypts the communication between a client and server, mainly between web browsers and web applications.

There are many differences between SSL and TLS protocols.

Secure Socket Protocol supports Fortezza Algorithms where Transport layer Protocol do not, also the versions of both protocols are very different SSL is version 3.0 and TLS is version 1.0 protocol.

The difference between SSL and TLS is that. In SSL the Message digest is used to create a master secret and provides the security services in communication. which are Authentication and confidentiality. While in TLS a randomly generated Pseudo function is used to create a master secret which provides higher security as compared to SSL.

What is SSL/TLS Handshake?

The SSL and TLS handshake establishes a system for SSL/TLS clients and servers to start communication between them in other words it is a negotiation between two parties on a network. Handshake Protocol is used to establish sessions. This protocol allows the client and server to verify each other by transferring a series of messages to each distance. Handshake protocol uses four phases to finalize its circle.

Steps enable the SSL or TLS client and server to communicate with each other:

Phase-1: Deciding which version of the Protocol to use. The system decides which protocol to use. Client and Server exchange hello-packets with each other to confirm. In this IP session, cipher suite, and Agree on which version of the protocol to use.
Phase-2: Server sends his certificate and Server-key-exchange. The server end phase-2 by exchanging the hello packet.
Phase-3: Verification, in this phase, the Client replies to the server by sending his certificate and Client-exchange-key.
Phase-4: In this phase, the Change Cipher suite is passed and all the verifications and security checks are done after this Handshake Protocol ends.

What is Cipher Suite?

A Cipher suite is a set of encryption rules that decides how the TLS handshake works. TLS/SSL protocols use some algorithms from a cipher suite to generate keys and encrypt information so that the communication is end-to-end encrypted.

A cipher Suite specifies one algorithm for each of the following tasks

Key Exchange Algorithms: This algorithm protects the information required to create shared keys.
Bulk Encryption Algorithms: Bulk encryption algorithms are those algorithms that encrypt the messages exchanged between clients and servers.
Message Authentication Algorithms: Message authentication algorithms generate messages and signatures that ensure the Combination of a message.

Conclusion

SSL/TLS handshake lets client and server follow a process to form a secure connection. Firstly, it involves the client sending its "client hello" message to the server after which the server replies with its own "server hello" message that selects encryption algorithms. Then, the server sends its digital certificate to the client for verification purposes. The client generates a pre-master secret that is encrypted using the public key of the server before sending it back. With this secret both parties come up with session keys they use during secure communication. Lastly, in order to approve if this handshake has been finalized or not, clients and servers exchange their "finished" messages. This way they can be sure that they are communicating securely through encryption.