Secure Socket Layer (SSL) is a standard security technology that establishes an encrypted link between a web server and a browser. This ensures that any data transferred between the two remains private and integral, protecting sensitive information like passwords and credit card numbers. SSL works by using a combination of public and private keys to encrypt data. When a user connects to a website that uses SSL, their browser checks the site's SSL certificate to confirm its authenticity. If the certificate is valid, a secure connection is established, allowing safe communication over the internet.