In the context of the rapid development of mobile technology, the use of Integrated Media Professional Generated Content (PGC) in portable devices is showing a significant growth trend. However, this growth trend is accompanied by an increase in network security risks. To address the increasingly serious embedded security threats in the handheld PGC field, this article proposes an innovative blockchain infrastructure. The core of this architecture is to combine smart contracts with decentralized storage technology to ensure effective maintenance of content authenticity and security. Through the distributed ledger technology of blockchain, its inherent consensus mechanism, and the immutability of data, media assets have received unprecedented and rigorous protection. The automatic execution and verification functions of smart contracts further enhance the reliability of data, providing strong guarantees for the secure transmission and storage of content. Through the construction of the system prototype and detailed performance testing, this article verifies the practicality and efficiency of the proposed model. This study provides new strategies for the security protection of mobile devices, laying a solid foundation for the deep integration of blockchain technology and composite media. It also provides important references and references for future research and applications in related fields.