What is SSL?

SSL (Secure Sockets Layer) is a security protocol for establishing encrypted communication between two systems. It ensures confidentiality and integrity by encrypting data exchanged over networks.

Although SSL is often referred to, it has evolved into TLS (Transport Layer Security). However, the term SSL is still widely used.

Why is SSL Important?

SSL prevents unauthorized access to sensitive data, such as passwords, personal information, and financial transactions. It's commonly used in websites, APIs, and distributed systems (like Hadoop) to secure communication between services.

SSL Handshake Process Overview

The SSL handshake is the process used to establish a secure connection between a client and a server.

1. Client Hello: The client sends its SSL version, cipher suites, and a random number to the server.
2. Server Hello: The server responds with its SSL version, chosen cipher suite, a random number, and its certificate.
3. Key Exchange: The client sends a pre-master secret, encrypted with the server's public key.
4. Session Key Creation: Both client and server create a session key from the pre-master secret.
5. Finish Messages: Both parties exchange encrypted "Finished" messages.
6. Secure Communication: Data is encrypted and exchanged using the session key.