Work Experience

• Google inc, Mountain View.

  2013.5-2013.8, 2014.5-2014.8

  I worked as an engineering intern on CPU power modeling and prediction in infrastructure team. My mentor is Xiao Zhang, and I also received great help from two professors Jason Mars and Lingjia Tang. Outcome of the internship was a model which addressed the CPU power prediction for hyperthreading enabled server, and it was published in Usenix ATC.

Education

• University of Wisconsin Madison

  2012-2018

  I worked for Ph.D of computer science in cloud system security here. My advisor is Professor Michael Swift. My Ph.D dissertation designs and implements a new cloud authorization framework, which securely incorporates program identities and related security properties into authorization process, and enables new usage pattern like cross-tenant sharing on the cloud. The research contains several sub-projects: CQSTR, TapCon, and Latte. These projects addressed authorization issues at different layers of cloud software stack. More details can be found in my resume and projects.

  Professor Jeffrey Chase and Thomas Ristenpart also actively supervised my research. They contributed indispensable insights about my work. Besides, I really enjoyed working together with a few talented researchers here, including but not limited to Qiang Cao, Adam Everspaugh, Robert Jellinek, Liang Wang, and Lichao Yin. They either directly helped in design and implementation, or inspired me with brilliant ideas.

• Tsinghua University, Beijing.

  2009-2012

  I received my Master degree of computer science in high performance computing (HPC) here. I was advised by Professor Wenguang Chen, and I was a main participant in evaluations of Chinese top-3 super computers with a broad range of HPC applications. I also lead an Intel-sponsored project to evaluate public cloud like Amazon Web Service for HPC applications. During the three years, I collaborated with several amazing people on different projects, including Professor Xiaosong Ma, Professor Wei Xue, Professor Jidong Zhai, and an outstanding engineer Mingliang Liu who works for Salesforce at the moment. I learnt a lot from them.

• Beihang University, Beijing.

  2005 -2009

  I received my bachelor degree of computer science here. The greatest accomplishment I achieved here was falling in love with my wife.

Ph.D Research

Security of a system depends ultimately on its program identity, i.e. what codes run and how they are configured. However, accessing trustworthy program identities is fundamentally hard before. Recent progress in DevOps and well grounded trust in public platforms, such like Openstack and Kubernetes, have changed the ground for the cloud environment. My research seeks to incorporate program identities into cloud authorization systems with the help of IaaS cloud provider, and allows them to authorize access based on both requester's code identity and implied security properties, e.g. the firewall policy enforced on it.

CQSTR

CQSTR constructs a missing abstraction of current IaaS cloud, which we call Cloud Containers. A cloud container defines isolation policy of network and IaaS services. IaaS provider makes such policy immutable after creation and enforces it during the life of a cloud container. Further, IaaS exports the policy through a trusted database for third parties to prove the containment of a cloud container, i.e. secret data flowing into the cloud container can not be leaked in unwanted way. We implemented CQSTR on Openstack Kilo, and built a proof-of-concept version for Amazon Web Service by auditing the Cloud Trail logs. The performance overhead is negligible.

CQSTR Presentation on SoCC2016 (Keynote format) and Paper

TapCon

TapCon is an IaaS managed container service, which attests containers to their code identities. The key feature of TapCon is source based attestation, i.e. linking the running container to the authenticated source repository and tools that builds a container. TapCon leverages the unspoofable nature of cloud network, and allows users of TapCon to grant access based on a requesting container's unique network address. Authorization policy is expressed in first order logic, which is extensible and flexible. We implemented TapCon in Docker and Linux kernel, and currently we are integrating it to Kubernetes. There is literally no overhead for using TapCon.

Latte

Latte is the authorization framework we described in research statement. It provides a rich basis for authorization. It can authorize operations based on requester’s code identity, which includes source code, build environment and runtime configuration, as well as third-party endorsements of trustworthiness. Latte supports the layered environments common in cloud computing, such as Docker containers running within virtual machines, and distributed services such as the Spark data-analytics platform. We integrated Latte with OpenStack, Docker and Spark to demonstrate how Latte can be used to improve security and enable new usage scenarios, such as allowing untrusted parties to compute over private data. Adopting Latte requires few changes to application platforms. The overhead of Latte in most cases is zero. Both CQSTR and TapCon are exemplary platforms used in Latte.

Latte paper is under submission to SoCC2018. Here is a draft version.

About the Code

The code is available by email request. I am still organizing all the code repositories for above three projects. There are more than fifteen of Git repositories to clean up, so it takes some time.