What is 2 way SSL?

2-way SSL, also known as mutual SSL/TLS authentication, is a security mechanism where both the server and the client verify each other's identities using digital certificates to establish a secure connection.

I recommend using it when need for security is much higher (for example when processing medical or banking data).

How 2-way SSL works

The "handshake" process is as follows:

1. The client initiates the connection and sends a "Client Hello" message.

2. The server responds with a "Server Hello," sends its own certificate, and requests a certificate from the client.

3. The client verifies the server's certificate (checking if it was issued by a trusted Certificate Authority - CA).

4. The client sends its own certificate to the server.

5. The server verifies the client's certificate (checking its validity and if it was issued by a trusted CA).

6. If both verifications are successful, a session key is exchanged to encrypt the connection, and the secure link is established.

There are some scenarios when usage of 2-way SSL is recommended:

Feature	One-way SSL	Two-way SSL
Authentication	Only the server is authenticated.	Both the server and the client are authenticated.
Client Requirement	The client does not need a digital certificate.	The client must have a digital certificate.
Common Uses	Public websites, e-commerce.	Online banking, payment systems, API connections, VPNs, IoT.

If you need help with connecting your Salesforce org with any external system feel free to reach out ;)