The wide adoption of cloud greatly facilitates the sharing of explosively generated media content today, yet deprives content providers’ direct control over the outsourced media content. Thus, it is pivotal to build an encrypted cloud media center where only authorized access is allowed. Enforcing access control alone, however, cannot fully protect content providers’ interests, as authorized users may later become traitors that illegally redistribute media content to the public. Such realistic threat should have been seriously treated yet is largely overlooked in the literature. In this paper, we initiate the first study on secure media sharing with fair traitor tracing in the encrypted cloud media center, through a new marriage of proxy re-encryption (for secure media sharing) and fair watermarking (for fair traitor tracing). Our key insight is to fully leverage the homomorphic properties residing in proxy re-encryption to embrace operations in fair watermarking. Two protocols are proposed for different application scenarios. We also provide complexity analysis for performance, showing that our work can also be treated as secure outsourcing of fair watermarking, and thus kills two birds with one stone. We thoroughly analyze the security strengths and conduct extensive experiments to validate the effectiveness of our design.

中文翻译：

---

可以访问不能泄露：加密云媒体中心防范非法内容再分发

云的广泛采用极大地促进了当今爆炸性生成的媒体内容的共享，但剥夺了内容提供商对外包媒体内容的直接控制权。因此，构建一个仅允许授权访问的加密云媒体中心至关重要。然而，仅执行访问控制并不能完全保护内容提供商的利益，因为授权用户可能会成为向公众非法重新分发媒体内容的叛徒。这种现实的威胁本应受到认真对待，但在文献中却在很大程度上被忽视了。在本文中，我们通过代理重加密（用于安全媒体共享）和公平水印（用于公平叛徒追踪）的新结合，在加密云媒体中心启动了具有公平叛徒追踪的安全媒体共享的首次研究。我们的主要见解是充分利用代理重加密中的同态属性来包含公平水印中的操作。针对不同的应用场景提出了两种协议。我们还提供了性能的复杂性分析，表明我们的工作也可以被视为公平水印的安全外包，从而一石二鸟。我们彻底分析了安全优势并进行了大量实验以验证我们设计的有效性。从而用一颗石头杀死两只鸟。我们彻底分析了安全优势并进行了大量实验以验证我们设计的有效性。从而用一颗石头杀死两只鸟。我们彻底分析了安全优势并进行了大量实验以验证我们设计的有效性。