【摘要】 目前IBE已经成为公钥加密领域的一个研究热点,而安全性是构建IBE方案的重要因素.在设计公钥加密方案时,通常主要考虑在各种攻击模型下所要达到的安全目标,使用安全目标与攻击模型相结合的方式来定义安全性.在对已提出的IBE方案进行归纳分析的基础上,概括了IBE安全性的形式化定义;总结了安全性所依赖的各种数学难题基础,对各种数学难题之间的强弱关系进行了分析;进而,基于这些强弱关系描述了IBE安全性之间的相互转化规律以及达到高安全性的转化方法,这些方法有一个共同点,就是在加密方案的构造过程中使用了某种测试;接下来,从安全性和效率的角度对比了已提出的典型IBE方案,指出低安全性向高安全性转化必然会带来额外开销,导致效率下降;最后,总结了IBE的缺点、未来研究趋势以及开放性问题.更多还原

【Abstract】 Nowadays,identity-based encryption(IBE) has become a new research direction of public key encryption,and security is the most important factor for constructing an IBE scheme.When designing a public encryption scheme,security goals are usually considered by the standard of attack models.And then,the definition of security combines both security goal and attack models.After analyzing the proposed IBE schemes,the authors present the formalized definition of IBE security and provide the comparison with security of traditional public key encryption.They also summarize the various mathematical assumptions on which the security relies and study the relations among assumptions.Furthermore,transformation rules among securities and transformation methods to reach higher security are described,and it is pointed out that these transformation methods all use some test in the construction,i.e.,they give some additional disposal of ciphertext or factor construction in the encryption phase;meanwhile,they can verify the validity of ciphertext in the decryption phase.Later,also contrasted are the IBE schemes on the security and efficiency,which indicates that the transformation to reach higher security will reduce efficiency.Finally,the disadvantages of IBE,future research directions and open problems are summarized.更多还原