iOS ensures application security through a multi-layered approach, including app sandboxing, secure inter-process communication, and hardware-backed security features. App sandboxing isolates each app’s data and code execution, reducing potential risks from malicious apps. iOS’s secure communication protocols help protect sensitive data, while hardware-backed security features, such as the Secure Enclave, safeguard cryptographic keys and user authentication data. Developers can further enhance application security by following best practices, such as validating user input, implementing proper access controls, and using secure communication protocols.