What is SSL/TLS? Encryption and Secure Connections
Understand the cryptography behind SSL/TLS, how certificates work, and why HTTPS is mandatory for modern websites.
Key Takeaways
- •SSL/TLS encrypts data in transit between a client and a server.
- •It prevents man-in-the-middle attacks and eavesdropping.
- •HTTPS is simply the HTTP protocol running over a secure TLS connection.
How Encryption Works
Transport Layer Security (TLS), the successor to Secure Sockets Layer (SSL), uses asymmetric cryptography to securely exchange a symmetric session key. This ensures that any data (like passwords or credit card numbers) sent between your browser and the server is encrypted and unreadable to any intermediaries.
Digital Certificates
For TLS to work, the server must present a Digital Certificate issued by a trusted Certificate Authority (CA). This certificate mathematically proves that the server you are talking to is the legitimate owner of the domain, preventing attackers from impersonating the website.
The TLS Handshake
Before any data is exchanged, the client and server perform a 'handshake' to negotiate encryption algorithms and exchange keys. This process adds a slight latency overhead to the initial connection, though modern TLS 1.3 has optimized this to just one round trip.
Frequently Asked Questions
Is SSL the same as TLS?
Colloquially, yes. However, technically, SSL is an outdated and insecure protocol. All modern secure connections use TLS, but the term 'SSL certificate' is still widely used in the industry.