SSL Handshake: Overview, Sub-protocols & How it Works?

With every aspect of livelihood moving to the cloud, ensuring a safe space for private data is vital. The next pizza you buy using your credit card can be the gateway for bank frauds worth millions of dollars, should there be any lapse in privacy and security. SSL Handshake protocol was the first flag-bearer of this responsibility, and it paved the way for everything you browse on the internet today. The topics covered in this tutorial are:

1. What is the SSH Protocol?
2. SSL Protection
3. What are the Sub-Protocols in SSL?
4. Steps in SSL handshake
5. Future of SSL

Before getting started with the SSL handshake, first, understand what the SSL protocol implies and its purpose.

What Is the SSL Protocol?

SSL stands for a secure socket layer protocol. Developed in 1994 by Netscape, SSL is a cryptographic layer protocol that provides privacy and security to communication between a client and web server.

The secure socket layer works below the application layer and above the transport layer when it comes to following the OSI Model. Before it passes the data from the application to the TCP layer, SSL is the middleman whose work is to encrypt the data to preserve its value.

Below, you can see the entire SSL protocol stack.

This stack highlights the construction of the network infrastructure where SSL authentication and validation are performed.

Now that you have a basic idea of SSL, it’s time to know their purpose regarding the security fronts.

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SSL Protection

The secure socket layer protocol is primarily responsible for three parameters preservation:

• Authenticity: The transfer of information must be to the right pair of client and server. There should not be a lapse in judgment with identity and certificate verification.

• Integrity: Throughout the transmission route, the data in the tunnel should not be modified in any way by third parties to preserve the integrity of the data.

• Confidentiality: The encrypted information should not be visible to unauthorized personnel and malicious actors, hence keeping the contents of the data confidential.

They kept the above pillars of security intact by the four sub-protocols in the SSL protocol library. Now you will through each of them.

What Are the Sub-Protocols in SSL?

• Record Protocol: This is the part of the protocol responsible for preserving integrity and confidentiality. It encrypts the data to be transmitted using hashing functions to prevent snooping on by third parties.

• SSL Handshake Protocol: The part of SSL which handles the preservation of authenticity. There is a distinct process that follows the authentication of web servers and clients, which you will look into later in this lesson.

• Change Cipher Spec: The layer which informs the servers about the manner and state of encryption being followed for the particular session.

• Alert Protocol: It is used as a defense mechanism to be aware of the possible difficulties faced in the encryption process. It has specific codes about the level of alert necessary to be declared.

This was the entire family of the SSL protocol. Now you can dive into this topic, i.e. SSL Handshake protocol.

Steps in SSL Handshake

You can distribute the handshake into four different phases:

Phase 1:

• Client and server gets acquainted with a hello signal each.
• The client sends the SSL version, cipher suite, session ID, etc.
• The server returns a standard encryption algorithm chosen from the cipher suite and compression algorithm.

Phase 2:

• The server sends its authentication certificate and requests for client authentication.
• The server also sends its public encryption key.
• The phase with a server hello done message.

Phase 3:

• The client sends its authentication certificate after verifying the server with the respective certificate authorities (CAs).
• The client also sends a secret private key encrypted using the server’s previously received public key.

Phase 4:

• The client sends the status of the cipher functions along with a ‘finished’ message to end the handshake from its side.
• The server also sends the status of the cipher algorithms and ends with a ‘finished’ signal.
• They encrypt the data with the symmetric key client sent in phase 3.

With the end of phase 4, authentication is complete, and the SSL handshake has maintained the authenticity of the entire session between the client and server.

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Future of SSL

It has deprecated SSL encryption now, with its v2 and v3 being dropped by the Internet Engineering Task Force (IETF) in 2011 and 2015, respectively. There had been far too many security vulnerabilities to carry on official activities using the secure socket layer protocol.

A new standard named Transport Layer Security (TLS) has become the global standard for encrypting information between web servers and internet browsers. The TLS v1.3 was approved in early 2018, ensuring up-to-date standards of security and updates.

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How Can Simplilearn Help You?

SSL Handshake may have become depreciated over time, but the standards it set paved the way for TLS protocol to shine and learn from past mistakes. With so much change happening in the cybersecurity world, staying up to date with the latest market trends is highly encouraged to professionals looking to enter this line of business.

Simplilearn offers a “Cybersecurity Expert” course formulated to stay up to date with the latest advancements, powered by the best instructors who know the market inside and out. Equally lucrative to both working professionals and beginners alike, the course provides you with all the basic skills necessary to master the concepts to be job-ready the moment you are through the course.

Conclusion

This tutorial started with explaining the SSL protocol, its uses, the sub-protocols in SSL, and the SSL Handshake protocol and its working. This protocol, barring a few security vulnerabilities, has helped to shape the future of client-server encryption. Dwindling numbers of malware-injecting websites have been a direct consequence of advancements when it comes to SSL-based cryptography.

If you are interested in learning further about cryptography and cybersecurity and perhaps even build a successful career in the field of cybersecurity, definitely check out Simplilearn’s Cyber Security Expert Master’s program. Designed in collaboration with industry experts and delivered via our unique, effective and award winning bootcamp learning model, this program will allow you to master all top cybersecurity skills, techniques and tools that today’s top companies are looking for. Explore the course and take the next step now.

Do you have any queries for us regarding this topic? Feel free to leave your thoughts and comments below, and we will get back to you with an answer.