Essential technology for online banking security includes encryption, multi-factor authentication (MFA), and secure socket layer (SSL) protocols. Encryption protects sensitive information like account numbers and passwords during transmission, making it unreadable to unauthorized parties. MFA adds an additional layer of security by requiring users to provide multiple forms of verification before accessing their accounts. SSL protocols ensure a secure connection between users and the banking server, protecting data from interception. Together, these technologies help safeguard online transactions and build trust in digital banking.