The technology crucial for ensuring online privacy includes encryption, firewalls, and virtual private networks (VPNs). Encryption secures data by encoding it, making it unreadable to unauthorized users along its transmission path. Firewalls serve as barriers, monitoring and controlling incoming and outgoing network traffic based on predetermined security rules. VPNs further protect online activities by creating secure connections over public networks, masking the user's IP address and encrypting their internet traffic. Together, these technologies help prevent data breaches and unauthorized access, allowing individuals and organizations to maintain their privacy in the digital world.