Publications

Refine Results

(Filters Applied) Clear All

ASE: authenticated statement exchange

December 7, 2009
  |
Conference Paper
Author:
Benjamin W. Fuller
…
Published in:
2010 9th IEEE Int. Symp. on Network Computing and Applications, 7 December 2009, pp. 155-161.
Topic:
cryptography
R&D area:
R&D group:

Summary

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 framework and an accompanying software library, called "Authenticated Statement Exchange" (ASE), for helping applications implement persistent caching of application specific data. ASE supports secure caching of a number of predefined data types common to secure communication protocols and allows applications to define new data types to be handled by ASE. ASE is applicable to many applications. The paper describes the use of ASE in one such application, secure group chat. In a recent real-use deployment, ASE was instrumental in allowing secure group chat to operate over low-bandwidth satellite links.
READ LESS

Summary

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...

READ MORE
ASE: authenticated statement exchange

GROK secure multi-user chat at Red Flag 2007-03

November 17, 2008
  |
Conference Paper
Author:
Roger I. Khazan
…
Published in:
MILCOM 2008, 16-18 November 2008.
Topic:
cryptography
R&D area:
R&D group:

Summary

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

Summary

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

READ MORE
GROK secure multi-user chat at Red Flag 2007-03

Securing communication of dynamic groups in dynamic network-centric environments

October 23, 2006
  |
Conference Paper
Author:
Roger I. Khazan
…
Published in:
IEEE MILCOM 2006, 23-25 October 2006.
Topic:
cryptography
R&D area:
R&D group:

Summary

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 decentralized group encryption services, and explain our vision for designing such services. We then describe our solution, PKGE, at a high-level, and report on the prototype implementation, performance experiments, and a demonstration with GAIM/Jabber chat.
READ LESS

Summary

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...

READ MORE
Securing communication of dynamic groups in dynamic network-centric environments

A wide area network simulation of single-round group membership algorithms

July 27, 2005
  |
Conference Paper
Author:
Roger I. Khazan
…
Published in:
NCA 2005: 4th IEEE Int. Symp. on Network Computing and Applications, 27-29 July 2005, pp. 159-168.
Topic:
cryptography
R&D area:
R&D group:

Summary

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 performance to two leading GM protocols, Moshe and Ensemble. Our simulations show, consistently with theoretical results, that Sigma always terminates within one round of message exchange, faster than Moshe and Ensemble. Moreover, Sigma has less message overhead and produces virtually the same quality of views. We also observe that view-oriented GM in dynamic WAN-like environments is practical only in applications where GM need not respond to every disconnect immediately when detected. These applications are able, and prefer, to delay GM response and ignore transient disconnects, avoiding frequent futile view changes and associated overhead. We reference some applications in this category.
READ LESS

Summary

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...

READ MORE
A wide area network simulation of single-round group membership algorithms

Using leader-based communication to improve the scalability of single-round group membership algorithms

April 4, 2005
  |
Conference Paper
Author:
Roger I. Khazan
…
Published in:
IPDPS 2005: 19th Int. Parallel and Distributed Processing Symp., 4-8 April 2005, pp. 280-287.
Topic:
algorithms
R&D area:
R&D group:

Summary

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 all-to-all (A2A) type of communication among members. A2A protocols have been shown to perform worse than leader-based (LB) protocols in certain networks, due to greater message overhead and higher likelihood of message loss. Thus, although LB protocols often involve additional communication steps, they can be more efficient in practice, particularly in fault-prone networks with large numbers of participating nodes. In this paper, we present Leader-Based Sigma, which transforms the original all-to-all version into a more scalable centralized communication scheme, and discuss the rounds vs. messages tradeoff involved in optimizing GM algorithms for deployment in large-scale, fault-prone dynamic network environments.
READ LESS

Summary

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...

READ MORE
Using leader-based communication to improve the scalability of single-round group membership algorithms

Robust collaborative multicast service for airborne command and control environment

October 31, 2004
  |
Conference Paper
Author:
Roger I. Khazan
…
Published in:
IEEE MILCOM 2004, Vol. 3, 31 October - 3 November 2004, pp. 1666-1674.
Topic:
communications
R&D area:
R&D group:

Summary

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 their communication. Both of these goals are important for collaborative applications. In this paper, we describe RCM, its modular and flexible design, and a collection of simple, light-weight protocols that implement it. We also report on several experiments with an RCM prototype in a test-bed environment.
READ LESS

Summary

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...

READ MORE
Robust collaborative multicast service for airborne command and control environment

Group membership: a novel approach and the first single-round algorithm

July 25, 2004
  |
Conference Paper
Author:
Roger I. Khazan
Published in:
23rd ACM SIGACT-SIGOPS Symp. on Principles of Distributed Computing, PODC, 25-28 July 2004, pp. 347–356.
Topic:
cryptography
R&D area:
R&D group:

Summary

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 of the existing membership algorithms may require two or more rounds of message exchanges. Our algorithm demonstrates that the Membership problem can be solved simpler and more efficiently than previously believed. By itself, the algorithm may produce disagreement (that is, inconsistent, transient views) prior to the "final" view. Even though this is allowed by the problem specification, such views may create overhead at the application level, and are therefore undesirable. We propose a new approach for designing group membership services in which our algorithm for reaching Agreement on Views is combined with a filter-like mechanism for reducing disagreements. This approach can use the mechanisms of existing algorithms, yielding the same multi-round performance as theirs. However, the power of this approach is in being able to use other mechanisms. These can be tailored to the specifics of the deployment environments and to the desired combinations of the speed of agreement vs. the amount of preceding disagreement. We describe one mechanism that keeps the combined performance to within a single-round, and sketch another two.
READ LESS

Summary

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...

READ MORE
Group membership: a novel approach and the first single-round algorithm
121-127 of 127