'SSL (Secure Sockets Layer)' establishes secure, encrypted connections between servers and clients, such as websites and browsers. Essential for transmitting sensitive data, SSL protects information like login credentials and credit card numbers.

Developed by Netscape in 1995, SSL uses cryptographic keys for encryption. SSL certificates from CAs authenticate website identities and enable secure connections, recognizable by 'HTTPS' in URLs and a padlock icon in browsers.

SSL's role in web security extends beyond sensitive data handling, contributing to overall data integrity and user privacy on the internet.