中文摘要：

确定性有限自动状态机是能表示有限个状态以及在这些状态之间转移和动作等行为的数学模型.本文提出两种基于有限状态自动机策略的加密方案：第1种方案称为无消息负载方案,方案中密文关联到一有限自动机M而令牌关联到一个任意长的输入串w,系统能在密文空间和密钥空间测试是否令牌关联的输入串可以被密文中的自动机接受.同时给出了转换到素数阶群构建的方法.第2种方案以前种方案为原语,扩展到支持消息负载保密的方案,当自动机接受输入串时,可以成功从密文中提取明文.采用双系统加密技术,在静态安全假设下证明了该方案达到标准模型下自适应语义安全性.同时给出了两种方案的性能评测.所提出的方案可应用于隐私保护的安全外包计算、网络防火墙内容过滤、模板隐私保护的DNA比对等领域,文中给出了实际应用中的具体案例.

英文摘要：

Deterministic Finite Automata （DFA） is a useful mathematical tool in defining the finite states and describing the transition among these states. In this paper, we propose two adap- tively secure functional encryptions in the standard model that are based on DFA policies. In the first scheme, the ciphertext is associated with a DFA M and the token is associated with an arbitrary length string w, and there is a check algorithm to test whether the string w is accepted by the automata M in the key/ciphertext spaces. In the second scheme, we extend the first scheme to support payload confidentiality, in which the decryption can extract the encrypted message if the associated automata accepts the string. Using the technique of dual system encryption, we prove the schemes can achieve adaptive security under the static assumptions, and we then give the performance evaluation. We also provide the deployments in privacy-preserving outsource computation in cloud, text filtering in firewall, and privacy-carrying DNA match in decentralized network etc.