The technology at the core of virtual private networks (VPNs) is encryption, which secures data transmitted over the internet by creating a private tunnel. This technology protects user privacy and data integrity, preventing unauthorized access. VPNs use protocols like OpenVPN and L2TP to encrypt and encapsulate data, making it unreadable to potential eavesdroppers. By masking the user's IP address, VPNs also provide anonymity while browsing.