Research on privacy preservation for IoT focuses on safeguarding sensitive data generated and transmitted by interconnected devices while maintaining system functionality and efficiency. Key approaches include lightweight encryption and secure communication protocols suitable for resource-constrained devices, attribute-based and context-aware access control mechanisms, and anonymization techniques such as differential privacy and data obfuscation to protect user identities and location information. Additionally, secure data aggregation and sharing protocols enable collaborative analytics without compromising individual privacy, while blockchain and distributed ledger technologies offer tamper-resistant storage, secure logging, and decentralized trust. Overall, privacy-preserving solutions in IoT aim to balance security, usability, and scalability in increasingly connected environments.