What Is ‘2 Way SSL’ and How It Works?

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2 Way SSL and How It Works

“SSL/TLS in two ways? Are you serious? ” – We understand your perplexity entirely if this was your initial response upon learning about or reading about Two-way SSL or TLS. By any possibility, SSL is complex to figure out on its own. And it’s perfectly normal to have a facepalm when you learn about a form different from what you’re used to, like mutual authentication, instead of the standard one-way authentication. 

Keep reading, we’ll explain what two-way SSL is and how it functions to assist you in comprehending every intricate SSL-related topic. You may already be familiar with SSL, one-way SSL, so let’s go through that before moving directly into two-way SSL.

What is SSL (Secure Socket Layer)?

Secure Socket Layer (SSL) is the recognized standard for facilitating the secure connection between a client and server to guarantee data confidentiality and integrity is SSL (Secure Socket Layer). Over time, SSL has undergone changes, with many iterations addressing any weaknesses. The public first saw the initial version of SSL in 1995. It was followed by SSL V3 in 1996, TLS V1.0 in 1999, TLS V1.1 in 2006, and TLS V1.2 in 2008.

SSL Certificates employed an encryption method to conceal the data from hackers while it was in transit. An adversary could only see the connected IP address and port, as well as the approximate amount of data being exchanged if SSL certificates are being utilized in the conversations. The remainder of the URL was invisible to them.

TLS is nothing but an upgraded and effectively secure version of SSL. People frequently use TLS and SSL interchangeably.

Truststore: The Truststore holds the list of signature certificates, or CA certificates, that specifies which certificates the SSL protocol trusts. Sometimes referred to as Trust Keystore, it houses public keys and certificates that certificate authorities have issued.

Keystore: The Identity Key store is a private key repository that is only necessary when a server connects over SSL.

Important Note: A physical document can be a trust and a key store.

The fundamental idea is that When a client connects to a server with an SSL certificate, the SSL protocol activates, encrypting all data transferred between the client and the server.

SSL functions as a layer of security by operating directly on top of TCP (transmission control protocol). The other protocol levels can continue operating generally behind the SSL layer. Programs that function as SSL servers send their credentials in a signed digital certificate to an SSL client to verify that they are the entity they claim to be.

People can use SSL one-way or two-way to secure the data exchanged between a client and a server. Let’s quickly review the distinctions between the process of One-Way SSL and Two-Way SSL in this article.

The Process of One-Way SSL

Is the padlock icon visible in the address bar of your browser? Yes, it is an illustration of a one-way SSL connection. Alright, let’s clarify: An SSL/TLS certificate enables the creation of a secure (encrypted) link that connects two entities (your web server and the browser of your end-user). Furthermore, it permits authentication between the web server and the browser.

To ensure it receives data from the intended server, the client does the sole part of one-way SSL validation. To enable one-way SSL, servers share their public certificate with clients. The procedures involved in connecting to a server and transferring data between a client and server in a one-way SSL scenario are summarized here in high-level terms:

1. The client uses the HTTPS protocol to seek specific protected data from the server. The SSL/TLS handshake process is now underway.

2. The server sends the client an initial message and its public certificate.

3. The client confirms or validates the certificate they got. The client confirms the certificate for certificates confirmed (signed) by the Certification Authority (CA).

4. The random byte string that the SSL/TLS client transmits to the server allows both parties to calculate the secret key that will be used to encrypt the data in upcoming messages. The server’s public key is used to encrypt the random byte string itself.

Consequently, this is the process by which the web server is verified. We attribute to this “one-way SSL/TLS.” However, what distinguishes this from the mutual authentication, or two-way SSL, process?

The Process of Two-Way SSL: Dual-party authentication

Mutual SSL certificates, commonly referred to as two-way SSL certificates, are SSL certificates that require mutual authentication between the client and server for increased security.

You should be able to infer what two-way SSL is all about now that you know how one-way SSL/TLS works. In contrast to one-way SSL, two-way SSL requires client authentication or the validation of both the web server and the web browser.

Moreover, addition to the SSL/TLS certificate on the server, this method requires a client certificate (also known as a personal authentication certificate) on the end of the user. Each party confirms the other’s certification.

The following is a high-level overview of the procedures involved in connecting to a server and transferring data between a client and server when using two-way SSL:

1. The SSL/TSL handshake method began when the client sent an HTTPS protocol request for a secured resource.

2 The server sends the client its public certificate, and the server hello back.

3. The client confirms or validates the certificate they got. The client confirms the certificate for certificates signed by the Certification Authority (CA).

4. The client will give the server its public certificate if the server certificate is verified correctly.

5. The server checks and validates the certificate it got. For certificates signed by a CA, the server uses the certification authority (CA) to verify the certificate.

Wrap Up!

Therefore, which is preferable for you out of the two authentication methods—one way and two way? Inevitably, people use two-way SSL in scenarios where they only want to allow connections from a specific subset of individuals. It assists in reducing the possibility of fraud while making purchases online.

Businesses commonly use two-way SSL to restrict platform access to their staff members and clients. While some businesses may decide to employ allowlists of IP addresses to limit user access, this is not the best course of action because IP spoofing is becoming more common.

Janki Mehta

Janki Mehta is a Cyber-Security Enthusiast who constantly updates herself with new advancements in the Web/Cyber Security niche. Along with theoretical knowledge, she also implements her practical expertise in day-to-day tasks and helps others to protect themselves from threats.