The technology used to secure websites and encrypt data transferred between a web server and a browser is SSL, or Secure Sockets Layer. SSL is a protocol that creates a secure connection by encrypting data transmitted over the internet. This encryption ensures that sensitive information, such as passwords and credit card details, remains confidential and protected from eavesdropping. SSL certificates, which verify the authenticity of a website, are essential for building user trust, making SSL a critical component of online security.