Publications

We have designed and implemented a general-purpose cryptographic building block, called GROK, for securing communication among groups of entities in networks composed of high-latency, low-bandwidth, intermittently connected links. During the process, we solved a number of non-trivial system problems. This paper describes these problems and our solutions, and motivates and...

Applications often re-transmit the same data, such as digital certificates, during repeated communication instances. Avoiding such superfluous transmissions with caching, while complicated, may be necessary in order to operate in low-bandwidth, high-latency wireless networks or in order to reduce communication load in shared, mobile networks. This paper presents a general...

This paper describes the GROK Secure Chat experimental activity performed by MIT Lincoln Laboratory at USAF Red Flag 2007-03 exercises and its results.

We developed a new approach and designed a practical solution for securing communication of dynamic groups in dynamic network-centric environments, such as airborne and terrestrial on-the-move networks. The solution is called Public Key Group Encryption (PKGE). In this paper, we define the problem of group encryption, motivate the need for...

A recent theoretical result proposed Sigma, a novel GM protocol that forms views using a single-round of message exchange. Prior GM protocols have required more rounds in the worst-case. In this paper, we investigate how well Sigma performs in practice. We simulate Sigma using WAN connectivity traces and compare its...

Sigma, the first single-round group membership (GM) algorithm, was recently introduced and demonstrated to operate consistently with theoretical expectations in a simulated WAN environment. Sigma achieved similar quality of membership configurations as existing algorithms but required fewer message exchange rounds. We now consider Sigma in terms of scalability. Sigma involves...

RCM (Robust Collaborative Multicast) is a communication service designed to support collaborative applications operating in dynamic, mission-critical environments. RCM implements a set of well-specified message ordering and reliability properties that balance two conflicting goals: a)providing low-latency, highly-available, reliable communication service, and b) guaranteeing global consistency in how different participants perceive...

We establish a new worst-case upper bound on the Membership problem: We present a simple algorithm that is able to always achieve Agreement on Views within a single message latency after the final network events leading to stability of the group become known to the membership servers. In contrast, all...