Abdel El-Sawy

2003 46th Midwest Symposium on Circuits and Systems, 2003

Reducing the Risk of the Honest Dealer Assumption in Robust Threshold RSA Function Sharing

In threshold signatures, there are n parties (players) sharing the signature key in a way that no... more In threshold signatures, there are n parties (players) sharing the signature key in a way that no subset of t or less players can generate the signature, while any subset of 1  t or more players can perform the signature correctly, where t is the threshold. The shares of the private key are set and distributed by an honest dealer. The problem with such protocols is that the dealer himself is a single point of failure, any adversary who compromises the dealer can forge the signature. Full keydistribution protocols allow the players to jointly generate the RSA modulus N, the public key e and to distribute shares of the secret key d among themselves without the help of a trusted dealer; this method has the advantage of removing the dealer and consequently avoids the risky assumption of his full honesty. However, the computation and communication complexity increase rapidly as the number of players grows. In this paper we propose a midway solution aiming to reduce the risk paid by the players when trusting only a single dealer and at the same time reduces the complexity of the employed key distribution protocol. We first prove that for limited number of players, the monotone circuit construction for secret sharing is more efficient than the shares backup notion [18] then we propose two multi-dealer protocols for the sharing of the RSA function, a protocol which is efficient for large number of players and another protocol that proves efficiency for smaller number of players. In both protocols the distribution of the secret key is performed by m dealers where m is expected to be much less than the number of players n.

Fully Distributed and Robust Threshold RSA Function Sharing Efficient for Small Number of Players

Robust threshold digital signature schemes are group signature schemes aiming to depart from the ... more Robust threshold digital signature schemes are group signature schemes aiming to depart from the classical one person signer schemes. The term 'robust' means that such schemes can tolerate errors attempted by malicious adversary and the term 'threshold' means that given a total of n players, no coalition of players with cardinality less than or equal to the threshold value can perform the signature while any coalition of players exceeding the threshold value can perform the signature correctly. The monotone circuit construction for secret sharing has the appealing property that the distributed secret is reconstructed by simple modulo addition and does not depend on polynomial interpolation which makes it adequate for the RSA function sharing. In this paper we show that when the number of players incorporated in the protocol is small, employing the monotone circuit construction for the design of robust threshold RSA function sharing is more efficient than the technique proposed by Rabin . Based on the monotone circuit construction, RSA function sharing can be efficiently designed in a fully distributed and robust way. The contributions in this paper are mainly two fold: First, we give two protocols in the presence of an honest dealer, one protocol can stand against eavesdropping and halting adversary, the other protocol can face a malicious adversary. Second, we present two protocols to get rid of the dealer by employing an extension to Cocks scheme [3] and extending Blackburn et al scheme [4] for distributing the secret key, one protocol stands against honest but curious players and the other protocol can withstand a malicious adversary. The schemes are robust since during the signature process, players can verify the validity of the broadcasted partial signatures. of all subsets of cardinality t+1 and Qual  represents the set of all subsets of cardinality at least

Trust Model for TRIDNT trust based routing protocol

by Dr-Ahmed M Abd El-haleem, Ihab Ali, and Abdel El-Sawy

Page 1. 2010 2nd International Conference on Computer Technology and Development (ICCTD 2010) Tru... more

A new hierachical routing method for broadband ISDN

Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109), 1998

A new hierarchical routing model for broadband networks is proposed and one of the problems facin... more A new hierarchical routing model for broadband networks is proposed and one of the problems facing the design of the hierarchical routing model is addressed. A brief description of the PNNI hierarchical routing model is given and a new hierarchical model that proves to be simpler and requires less storage than the PNNI model is proposed. The problem addressed is

Multiple Encryption Multiple Modes With Optimal Secret Parameters

A robust threshold elliptic curve digital signature providing a new verifiable secret sharing scheme

A new hierachical routing method for broadband ISDN

Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109), 1998

An Unusual Transorbital Penetrating Injury and Principles of Management

Craniomaxillofacial Trauma and Reconstruction, 2014

The objective of this study was to present an unusual low velocity transorbital penetrating injur... more The objective of this study was to present an unusual low velocity transorbital penetrating injury. The study design was a clinical record (case report). A 38-year-old gentleman tripped and fell face first onto the wing of an ornamental brass eagle. This penetrated the inferomedial aspect of the right orbit, breaching the lamina papyracea to extend into the ethmoid sinuses and reaching the dura of the anterior cranial fossa. The foreign body was removed in theater under a joint ophthalmology and ENT procedure. The patient was left with reduced visual acuity in the right eye but no other long-term sequelae. Transorbital penetrating injury presents unusual challenges to investigation and management requiring a multidisciplinary approach to prevent significant morbidity and mortality. If managed well the prognosis is good.

TRIDNT: Isolating Dropper Nodes with Some Degree of Selfishness in MANET

Communications in Computer and Information Science, 2011

... 247 10. Gong, W., You, Z., Chen, D., Zhao, X., Gu, M., Lam, K.-Y.: Trust Based Routing for Mi... more

Trust Model for TRIDNT trust based routing protocol

Page 1. 2010 2nd International Conference on Computer Technology and Development (ICCTD 2010) Tru... more

2003 46th Midwest Symposium on Circuits and Systems, 2003

Reducing the Risk of the Honest Dealer Assumption in Robust Threshold RSA Function Sharing

Fully Distributed and Robust Threshold RSA Function Sharing Efficient for Small Number of Players

Trust Model for TRIDNT trust based routing protocol

by Dr-Ahmed M Abd El-haleem, Ihab Ali, and Abdel El-Sawy

Page 1. 2010 2nd International Conference on Computer Technology and Development (ICCTD 2010) Tru... more

A new hierachical routing method for broadband ISDN

Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109), 1998

Multiple Encryption Multiple Modes With Optimal Secret Parameters