题目一：On formal frameworks for security modeling

内容简介：Formal methods have been frequently used in the context of security. Examples include to find weaknesses in cryptographic protocols, to prove the security of protocols, to generate access-control policies or to specify security properties of business processes. This talk reviews several approaches to formally model security and highlights strength and weaknesses of the different approaches. It will look at logic-based methods for security protocols, generic formal attack models, model-checking and theorem proving for security and tools supporting some of these methods.

Finally, a rather generic formal-languages based framework for formal security modelling is presented that supports the exact specification of security requirements for the support of security engineering processes.

报告人：Associate Professor  Carsten Rudolph  Monash University

时  间：2016年4月29日（周五）上午8：30～10：00

题目二：Extended Proxy-Assisted Approach: Achieving Revocable Fine-Grained Encryption of Cloud Data

内容简介：Attribute-based encryption has the potential to be deployed in a cloud computing environment to provide scalable and fine-grained data sharing. However, user revocation within ABE deployment remains a challenging issue to overcome, particularly when there is a large number of users. In this work, we introduce an extended proxy-assisted approach, which weakens the trust required of the cloud server. Based on an all-or-nothing principle, our approach is designed to discourage a cloud server from colluding with a third party to hinder the user revocation functionality. We demonstrate the utility of our approach by presenting a construction of the proposed approach, designed to provide efficient cloud data sharing and user revocation. A prototype was then implemented to demonstrate the practicality of our proposed construction.

报告人：Senior Lecturer  Joseph Liu  Monash University

时  间：2016年4月29日（周五）上午10：00～11：30

题目三：Improved security proofs in lattice-based cryptography: using the Renyi divergence rather than the statistical distance

内容简介：In lattice-based cryptography, there is often a `security gap' between hard lattice problems and the cryptographic schemes and their implementations that rely on those hard problems. This gap arises due to the use of 'imperfect' probability distributions in the schemes rather than the 'ideal' probability distributions used in the hard problems. The standard approach to quantify this `security gap' is based on measuring the statistical distance (SD) between the `ideal' and `imperfect' distributions, but this approach often leads to significant efficiency costs. In this talk, we present an alternative approach to quantifying the `security gap', based on the Renyi divergence (RD) between the `ideal' and `imperfect' distributions. We show several examples in lattice-based cryptography where the use of RD instead of SD provides efficiency savings in the cryptographic scheme for the same proven security level.

报告人：Senior Lecturer  Ron Steinfeld  Monash University

时  间：2016年4月29日（周五）下午15：00～16：30

地  点：南海楼338室

热烈欢迎广大师生参加!

信息科学技术学院/网络空间安全学院

2016年4月25日