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The Rampart toolkit for building highintegrity services
 In Theory and Practice in Distributed Systems
, 1995
"... Abstract. Rampart is a toolkit of protocols to facilitate the development ofhighintegrity services, i.e., distributed services that retain their availability and correctness despite the malicious penetration of some component servers by an attacker. At the core of Rampart are new protocols that sol ..."
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Cited by 140 (7 self)
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Abstract. Rampart is a toolkit of protocols to facilitate the development ofhighintegrity services, i.e., distributed services that retain their availability and correctness despite the malicious penetration of some component servers by an attacker. At the core of Rampart are new protocols that solve several basic problems in distributed computing, including asynchronous group membership, reliable multicast (Byzantine agreement), and atomic multicast. Using these protocols, Rampart supports the development of highintegrity services via the technique of state machine replication, and also extends this technique with a new approach to server output voting. In this paper we give a brief overview of Rampart, focusing primarily on its protocol architecture. We also sketch its performance in our prototype implementation and ongoing work. 1
A HighThroughput Secure Reliable Multicast Protocol
 Journal of Computer Security
, 1996
"... A (secure) reliable multicast protocol enables a process to multicast a message to a group of processes in a way that ensures that all honest destinationgroup members receive the same message, even if some group members and the multicast initiator are maliciously faulty. Reliable multicast has been ..."
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Cited by 46 (8 self)
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A (secure) reliable multicast protocol enables a process to multicast a message to a group of processes in a way that ensures that all honest destinationgroup members receive the same message, even if some group members and the multicast initiator are maliciously faulty. Reliable multicast has been shown to be useful for building multiparty cryptographic protocols and secure distributed services. We present a highthroughput reliable multicast protocol that tolerates the malicious behavior of up to fewer than onethird of the group members. Our protocol achieves highthroughput using a novel technique for chaining multicasts, whereby the cost of ensuring agreement on each multicast message is amortized over many multicasts. This is coupled with a novel flowcontrol mechanism that yields low multicast latency. 1. Introduction Reliable multicast is a fundamental communication protocol that underlies many forms of secure distributed computation. A (secure) reliable multicast protocol en...
Parallel Algorithms for Integer Factorisation
"... The problem of finding the prime factors of large composite numbers has always been of mathematical interest. With the advent of public key cryptosystems it is also of practical importance, because the security of some of these cryptosystems, such as the RivestShamirAdelman (RSA) system, depends o ..."
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Cited by 41 (17 self)
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The problem of finding the prime factors of large composite numbers has always been of mathematical interest. With the advent of public key cryptosystems it is also of practical importance, because the security of some of these cryptosystems, such as the RivestShamirAdelman (RSA) system, depends on the difficulty of factoring the public keys. In recent years the best known integer factorisation algorithms have improved greatly, to the point where it is now easy to factor a 60decimal digit number, and possible to factor numbers larger than 120 decimal digits, given the availability of enough computing power. We describe several algorithms, including the elliptic curve method (ECM), and the multiplepolynomial quadratic sieve (MPQS) algorithm, and discuss their parallel implementation. It turns out that some of the algorithms are very well suited to parallel implementation. Doubling the degree of parallelism (i.e. the amount of hardware devoted to the problem) roughly increases the size of a number which can be factored in a fixed time by 3 decimal digits. Some recent computational results are mentioned – for example, the complete factorisation of the 617decimal digit Fermat number F11 = 2211 + 1 which was accomplished using ECM.
A Noninteractive PublicKey Distribution System
"... An identitybased noninteractive public key distribution system is presented that is based on a novel trapdoor oneway function allowing a trusted authority to compute the discrete logarithms modulo a publicly known composite number m while this is infeasible for an adversary not knowing the fac ..."
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Cited by 29 (0 self)
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An identitybased noninteractive public key distribution system is presented that is based on a novel trapdoor oneway function allowing a trusted authority to compute the discrete logarithms modulo a publicly known composite number m while this is infeasible for an adversary not knowing the factorization of m. Without interaction with a key distribution center or with the recipient of a given message, a user can generate a mutual secure cipher key based solely on the recipient's identity and his own secret key, and subsequently send the message, encrypted with the generated cipher used in a conventional cipher, over an insecure channel to the recipient. In contrast to previously proposed identitybased systems, no public keys, certificates for public keys or other information need to be exchanged and thus the system is suitable for certain applications that do not allow for interaction. The paper solves an open problem proposed by Shamir in 1984.
Prospects for Quantum Coherent Computation Using Superconducting Electronics
 IEEE Trans. Appl. Supercond
, 1997
"... We discuss the prospects and challenges for implementing a quantum computer using superconducting electronics. It appears that Josephson junction devices operating at milliKelvin temperatures can achieve a quantum dephasing time of milliseconds, allowing quantum coherent computations of 10 10 or ..."
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Cited by 23 (9 self)
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We discuss the prospects and challenges for implementing a quantum computer using superconducting electronics. It appears that Josephson junction devices operating at milliKelvin temperatures can achieve a quantum dephasing time of milliseconds, allowing quantum coherent computations of 10 10 or more steps. This figure of merit is comparable to that of atomic systems currently being studied for quantum computation. I. INTRODUCTION In quantum coherent computation information is coded not just as "1" and "0" but also as coherent superpositions of the "1" and "0" states of a quantum mechanical two state system. Recent experiments from atomic and optical physics have demonstrated the creation and manipulation of such quantum mechanical bits, socalled `qubits' [1][3], and consideration is being given to the prospects for constructing simple quantum computers. In this paper we will discuss the prospects for a superconducting electronics implementation of quantum computation. The great ...
Recent progress and prospects for integer factorisation algorithms
 In Proc. of COCOON 2000
, 2000
"... Abstract. The integer factorisation and discrete logarithm problems are of practical importance because of the widespread use of public key cryptosystems whose security depends on the presumed difficulty of solving these problems. This paper considers primarily the integer factorisation problem. In ..."
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Cited by 20 (1 self)
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Abstract. The integer factorisation and discrete logarithm problems are of practical importance because of the widespread use of public key cryptosystems whose security depends on the presumed difficulty of solving these problems. This paper considers primarily the integer factorisation problem. In recent years the limits of the best integer factorisation algorithms have been extended greatly, due in part to Moore’s law and in part to algorithmic improvements. It is now routine to factor 100decimal digit numbers, and feasible to factor numbers of 155 decimal digits (512 bits). We outline several integer factorisation algorithms, consider their suitability for implementation on parallel machines, and give examples of their current capabilities. In particular, we consider the problem of parallel solution of the large, sparse linear systems which arise with the MPQS and NFS methods. 1
Improvements to the general number field sieve for discrete logarithms in prime fields
 Mathematics of Computation
, 2003
"... Abstract. In this paper, we describe many improvements to the number field sieve. Our main contribution consists of a new way to compute individual logarithms with the number field sieve without solving a very large linear system for each logarithm. We show that, with these improvements, the number ..."
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Cited by 14 (1 self)
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Abstract. In this paper, we describe many improvements to the number field sieve. Our main contribution consists of a new way to compute individual logarithms with the number field sieve without solving a very large linear system for each logarithm. We show that, with these improvements, the number field sieve outperforms the gaussian integer method in the hundred digit range. We also illustrate our results by successfully computing discrete logarithms with GNFS in a large prime field. 1.
On The Oracle Complexity Of Factoring Integers
 COMPUTATIONAL COMPLEXITY
, 1996
"... The problem of factoring integers in polynomial time with the help of an (infinitely powerful) oracle who answers arbitrary questions with yes or no is considered. The goal is to minimize the number of oracle questions. Let N be a given composite nbit integer to be factored, where n = dlog 2 ..."
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Cited by 5 (0 self)
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The problem of factoring integers in polynomial time with the help of an (infinitely powerful) oracle who answers arbitrary questions with yes or no is considered. The goal is to minimize the number of oracle questions. Let N be a given composite nbit integer to be factored, where n = dlog 2 Ne. The trivial method of asking for the bits of the smallest prime factor of N requires n/2 questions in the worst case. A nontrivial algorithm of Rivest and Shamir requires only n/3 questions for the special case where N is the product of two n/2bit primes. In this paper, a polynomialtime oracle factoring algorithm for general integers is presented which, for any ffl ? 0, asks at most ffln oracle questions for sufficiently large N , thus solving an open problem posed by Rivest and Shamir. Based on a plausible conjecture related to Lenstra's conjecture on the running time of the elliptic curve factoring algorithm it is shown that the algorithm fails with probability at most N ...