Hierarchical organization is a fundamental structure in real-world society, where authority and responsibility are delegated from managers to subordinates. The VIRGO network (Virtual Hierarchical Overlay Network for scalable grid computing) provides a scalable overlay for organizing distributed systems but lacks intrinsic security and privacy mechanisms. This paper proposes Private Virtual Tree Networks (PVTNs), a cryptographically enforced extension that leverages the VIRGO overlay to mirror real organizational hierarchies. In PVTNs, join requests are encrypted with the manager's public key to ensure confidentiality, while membership authorization is enforced through manager-signed delegation certificates. Public keys are treated as organizational secrets and are disclosed only within direct manager-member relationships, resulting in a private, non-enumerable virtual tree. Our work demonstrates, through the system model, protocols, security analysis, and design rationale, that PVTNs achieve scalability, dynamic management, and strong security guarantees without relying on global public key infrastructures.

翻译：分层组织是现实社会中的基本结构，其中权力与责任由管理者向下属委派。VIRGO网络（可扩展网格计算的虚拟分层覆盖网络）为组织分布式系统提供了可扩展的覆盖层，但缺乏内在的安全与隐私机制。本文提出私有虚拟树网络（PVTNs），这是一种通过密码学强化的扩展方案，利用VIRGO覆盖层来映射真实的组织层级结构。在PVTNs中，加入请求使用管理者的公钥加密以确保机密性，而成员资格授权则通过管理者签名的委派证书强制执行。公钥被视为组织机密，仅在直接管理者-成员关系中披露，从而形成一个私有、不可枚举的虚拟树。通过系统模型、协议、安全分析和设计原理，我们的工作证明PVTNs能够在无需依赖全局公钥基础设施的情况下，实现可扩展性、动态管理和强大的安全保证。