针对近年新提出的PPCD组合文档(Publicly Posted Composite Documents)在用户授权期后的安全删除问题，提出 基于身份的分层加密的组合文档安全删除方案（HICDSS）。通过将处于不同安全等级的文档组件用不同的随机对称加密密 钥加密和用基于身份的分层加密(Hierarchical Identity Based Encryption，HIBE)系统将对称加密密钥进行加密；然后，运用混合 算法将组合文档的部分密文和对称加密密钥的密文做处理成混合密文；接着，使用对象存储系统(Object Storage System，OSS) 对混合密文份进行存储；最后，对该方案的综合安全性进行分析证明。

To deal with the issue of lifecycle security of Publicly Posted Composite Documents (PPCD) which was proposed in re- cent years, in this paper, we propose a Secure Self-Destruction Scheme for Publicly Posted Composite Documents with Hierarchical Identity-based Encryption (HICDSS), which can protect a user’s sensitive PPCD automatically destructed after a period of time. We form a new structure of the PPCD with different security levels. We firstly encrypt the different security documents into ciphertexts by different symmetric keys and encrypt the symmetric keys using the HIBE algorithm; then use the Mingle Shares Generaion algo- rithm to make the part of document’s ciphertext and the symmetric key’s ciphertext into mixed ciphertext, and sent the mixed ci- phertext into the Object Storage System; finally we analyze and prove the security, efficiency and performance of the HICDSS scheme.