Browsing by Author "Poovendran, R."
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Item A Decision-Process Analysis of Implicit Coscheduling(2000) Poovendran, R.; Keleher, P.; Baras, John S.; Baras, John S.; ISR; CSHCNThis paper presents a theoretical framework based on Bayesian decision theory for analyzing recently reported results on implicit coscheduling of parallel applications on clusters of workstations. Using probabilistic modeling, we show that the approach presented can be applied for processes with arbitrary communication mixes. We also note that our approach can be used for deciding the additional spin times in the case of spin-yield.Finally, we present arguments for the use of a different notion of fairness than assumed by prior work.International Conference on Parallel and Distributed Computing
Item A Distributed Shared Key Generation Procedure Using Fractional Keys(1998) Poovendran, R.; Corson, M. Scott; Baras, John S.; ISR; CSHCNWe present a new class of distributed key generation and recoveryalgorithms suitable for group communication systems where the groupmembership is either static or slowly time-varying, and must be tightlycontrolled.The proposed key generation approach allows entities whichmayhave only partial trust in each other to jointly generate a shared keywithout the aid of an external third party. The group collectivelygenerates and maintains a dynamic group parameter, and the shared key isgenerated using a strong, one-way function of this parameter.
This schemealso provides perfect forward secrecy. The validity of key generation canbe checked using verifiable secret sharing techniques. The key retrievalmethod does not require the keys to be stored in an external retrievalcenter.
We note that many Internet-based applications may have theserequirements. Fulfillment of these requirements is realized through theuse of fractional keys--a distributed technique recently developed toenhance the security of distributed systems in a non-cryptographicmanner.
Item Dynamic Elgamal Public Key Generation with Tight Binding(1999) Poovendran, R.; Corson, M. Scott; Baras, John S.; Baras, John S.; ISR; CSHCNWe present a new distributed, group ElGamal public key generation algorithm which also permits maintenance of a group-specific, dynamic, individual ElGamal public key infrastructure. We parameterize the group with a time-varying quantity that serves as a distributed mechanism for controlling key generation privilege.Our scheme can be viewed as an alternative to polynomial schemes where, at the time of the secret construction step, there has to be a third party or a black box to combine the shares. Also, in polynomial schemes, at the time of combining,the individual shares of the secret have to be revealed to the third party.
In our scheme, the common secret can be generated without ever exposing the individual shares constructing it. We note that many of the recently proposed distributed key management schemes need such group keys for certification and signing purposes.
3rd Annual Conference on Advanced Telecommunications and Information Distribution Research Program (ATIRP)
Item Dynamic ElGamal Public Key Generation with Tight Binding(1999) Poovendran, R.; Corson, M. Scott; Baras, John S.; ISR; CSHCNWe present a new distributed, group ElGamal public key generation algorithm which also permits maintenance of a group-specific, dynamic,individual ElGamal public key infrastructure.We parameterize the group with a time-varying quantity that servesas a distributed mechanism for controlling key generation privilege.
Our scheme can be viewed as an alternative to polynomial schemes where, at the time of the secret construction step, there has to be a third party or a black box to combine the shares. Also, in polynomial schemes, at the time of combining, the individual shares of the secret have to be revealed to the third party. In our scheme, the common secret can be generated without ever exposing the individual shares constructing it.
We note that many of the recently proposed distributed key management~[2-4] schemes need such group keys for certification and signing purposes.
Item An Information Theoretic Analysis of Rooted-Tree Based Secure Multicast Key Distribution Schemes(1999) Poovendran, R.; Baras, John S.; Baras, John S.; ISR; CSHCNSeveral variations of rooted tree based solutions have been recently proposed for member revocation in multicast communications.In this paper, we show that by assigning probabilities for member revocations, the optimality, correctness, and the system requirements of some of these schemes can be systematically studied using information theoretic concepts.
Specifically, we show that the optimal average number of keys per member in a rooted tree is related to the entropy of the member revocation event.
Using our derivations, we show that (a) the key assignments in correspond to the maximum entropy solution, (b) and direct application of source coding will lead to member collusion (we present recently proposed solutions as examples of this) and a general criteria that admits member collusion. We also show the relationship between entropy of member revocation event and key length.
Crypto '99 :: 19th Annual IACR Crypto Conference
Item Key Management for Secure Multicast Communications(1999) Poovendran, R.; Baras, J.S.; ISR; CSHCNThis dissertation considers the single sender, multiple receiver model of secure multicast communication. The goal is to develop schemes that have reduced computational overhead at the time of key generation, minimize the amount of message units required at the time of key updates, andminimize the number of keys to be stored by the sender as well as receivers.In order to achieve this goal, a key generation and distribution architecture based on rooted trees and control panels is proposed. A control panel is assumed to consist of mutually suspicious members who jointly generate the keys that are distributed to the rest of the members. Based on the assumption about the control panel, we provide a distributed key generation mechanism which allows a set of mutually suspicious members to contribute to the generation of a joint secret without revealing their individual contributions. The key distribution scheme presented considers the member revocation event and relates it to the key assignment of individual users. We define and show that the entropy of the member revocation event plays an important role in determining the number of keys assigned to a member. We claim that the number of keys allocated to a member based on the elementary concepts from information theory will also correspond to the minimum number of keys that need to be assigned to a member unless additional functional relationship among keys exists, since it "completely captures" the uncertainty of the member revocation event. We also identify some weaknesses in the recent schemes, and solvean open problem posed at Eurocrypt'99.Item A Scalable Extension of Group Key Management Protocol(1998) Poovendran, R.; Ahmed, Sarah N.; Corson, M. Scott; Baras, John S.; ISR; CSHCNThis paper presents a robust, scalable extension to the recently proposed multicast Group Key Management Protocol (GKMP) ([1], [2]), in terms of security administration. The GKMP has two major security related problems: (a) lack of any mechanism to remove a compromised group administrator, and (b) lack of scalability. We are able to remove a compromised single panel member from generating the group keys by setting the panel members with shared authority to generate the group keys. We then introduce the sub-controllers who have all the functionalities of the group control panel except the authority to generate the group keys. The sub-control panel helps scalability of the network in terms of the security operations. The sub-controllers are chosen using a threshold-based clustering algorithm.This paper was presented at the "ATIRP ARL Federated Laboratory 2nd Annual Conference," Feb. 5-6, 1998, University of Maryland, College Park Campus.