SSL/TLS Basics

Introduction

Secure Sockets Layer (SSL) and Transport Layer Security (TLS) are cryptographic protocols designed to provide secure communication over a computer network. TLS is the successor to SSL and is widely used for securing internet connections, particularly in web browsing.

What is SSL/TLS?

SSL and TLS are protocols that encrypt data sent over the internet, ensuring confidentiality, integrity, and authenticity. They work by creating a secure connection between the client and server.

How SSL/TLS Works

1. Client connects to server and requests a secure connection.
2. Server responds with its SSL/TLS certificate.
3. Client verifies the server's certificate against trusted Certificate Authorities (CAs).
4. Both parties agree on encryption methods and session keys.
5. Data transfer begins, encrypted using the session keys.

SSL/TLS Handshake Process

sequenceDiagram
                participant Client
                participant Server
                Client->>Server: ClientHello
                Server->>Client: ServerHello + Certificate
                Client->>Server: ClientKeyExchange
                Server->>Client: ServerHelloDone
                Client->>Server: ChangeCipherSpec
                Client->>Server: Finished
                Server->>Client: ChangeCipherSpec
                Server->>Client: Finished
            

The handshake establishes the parameters for the secure session, including the cryptographic keys and algorithms to be used.

Best Practices

• Use the latest version of TLS (currently TLS 1.3).
• Regularly update your server and application software.
• Implement strong cipher suites.
• Obtain SSL/TLS certificates from trusted CAs.
• Use HTTP Strict Transport Security (HSTS) to enforce HTTPS.

FAQ