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Fully distributed threshold RSA under standard assumptions
 ADVANCES IN CRYPTOLOGY — ASIACRYPT 2001, VOLUME ??? OF LNCS
, 2001
"... The aim of this article is to propose a fully distributed environment for the RSA scheme. What we have in mind is highly sensitive applications and even if we are ready to pay a price in terms of efficiency, we do not want any compromise of the security assumptions that we make. Recently Shoup propo ..."
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Cited by 22 (3 self)
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The aim of this article is to propose a fully distributed environment for the RSA scheme. What we have in mind is highly sensitive applications and even if we are ready to pay a price in terms of efficiency, we do not want any compromise of the security assumptions that we make. Recently Shoup proposed a practical RSA threshold signature scheme that allows to share the ability to sign between a set of players. This scheme can be used for decryption as well. However, Shoup’s protocol assumes a trusted dealer to generate and distribute the keys. This comes from the fact that the scheme needs a special assumption on the RSA modulus and this kind of RSA moduli cannot be easily generated in an efficient way with many players. Of course, it is still possible to call theoretical results on multiparty computation, but we cannot hope to design efficient protocols. The only practical result to generate RSA moduli in a distributive manner is Boneh and Franklin’s protocol but it seems difficult to modify it in order to generate the kind of RSA moduli that Shoup’s protocol requires. The present work takes a different path by proposing a method to enhance the key generation with some additional properties and revisits Shoup’s protocol to work with the resulting RSA moduli. Both of these enhancements decrease the performance of the basic protocols. However, we think that in the applications we target, these enhancements provide practical solutions. Indeed, the key generation protocol is usually run only once and the number of players used to sign or decrypt is not very large. Moreover, these players have time to perform their task so that the communication or time complexity are not overly important.
Two contradictory conjectures concerning Carmichael numbers
"... Erdös [8] conjectured that there are x 1;o(1) Carmichael numbers up to x, whereas Shanks [24] was skeptical as to whether one might even nd an x up to which there are more than p x Carmichael numbers. Alford, Granville and Pomerance [2] showed that there are more than x 2=7 Carmichael numbers up to ..."
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Cited by 12 (0 self)
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Erdös [8] conjectured that there are x 1;o(1) Carmichael numbers up to x, whereas Shanks [24] was skeptical as to whether one might even nd an x up to which there are more than p x Carmichael numbers. Alford, Granville and Pomerance [2] showed that there are more than x 2=7 Carmichael numbers up to x, and gave arguments which even convinced Shanks (in persontoperson discussions) that Erdös must be correct. Nonetheless, Shanks's skepticism stemmed from an appropriate analysis of the data available to him (and his reasoning is still borne out by Pinch's extended new data [14,15]), and so we herein derive conjectures that are consistent with Shanks's observations, while tting in with the viewpoint of Erdös [8] and the results of [2,3].
The distribution of Lucas and elliptic pseudoprimes
, 2001
"... Let L(x) denote the counting function for Lucas pseudoprimes, and E(x) denote the elliptic pseudoprime counting function. We prove that, for large x, L(x) ≤ x L(x) −1/2 and E(x) ≤ x L(x) −1/3, where L(x) = exp(log xlog log log x / log log x). ..."
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Cited by 9 (1 self)
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Let L(x) denote the counting function for Lucas pseudoprimes, and E(x) denote the elliptic pseudoprime counting function. We prove that, for large x, L(x) ≤ x L(x) −1/2 and E(x) ≤ x L(x) −1/3, where L(x) = exp(log xlog log log x / log log x).
Finding Four Million Large Random Primes
 In Crypto '90, LNCS 537
"... e theory also suggests that pseudoprimes are rare. On the basis of extensive experience and analysis, Pomerance [5, 8] conjectures that the number of pseudoprimes less than n is at most n=L(n) 1+o(1) (2) where L(n) = exp log n log log log n log log n ! : Supported by NSF grant CCR8914428 ..."
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Cited by 5 (0 self)
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e theory also suggests that pseudoprimes are rare. On the basis of extensive experience and analysis, Pomerance [5, 8] conjectures that the number of pseudoprimes less than n is at most n=L(n) 1+o(1) (2) where L(n) = exp log n log log log n log log n ! : Supported by NSF grant CCR8914428, and RSA Data Security. email address: rivest@theory.lcs.mit.edu If this conjecture is correct, and we make the (unjustied) additional assumption that the o(1) in conjecture (2) can be ignored, then the number of pseudoprimes less than 2 256 is conjectured to be at most 4 10 52 whereas the number of 256bit primes is approximately 6:5 10 74 : Thus, if Pomerance's conjecture
Generalized Carmichael Numbers
, 2001
"... Algebra in particular about finite fields, rings and polynomials over finite fields and rings. With the end of first semester we had done preliminary investigation and we had identified the Generalized Carmichael Numbers. First four chapters of this report have been written during that period. By th ..."
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Algebra in particular about finite fields, rings and polynomials over finite fields and rings. With the end of first semester we had done preliminary investigation and we had identified the Generalized Carmichael Numbers. First four chapters of this report have been written during that period. By the beginning of second semester we had found Generalized Carmichael numbers of order 2 and we started to do things in different directions. We concentrated on proving a bound on number of Generalized Carmichael Numbers. We had found the result of chapter 6 by midterm.
POSITIVE INTEGERS n SUCH THAT na σ(n) − 1
"... Abstract. For a positive integer n let σ(n) be the sum of divisors function of n. In this note, we fix a positive integer a and we investigate the positive integers n such that na σ(n) − 1. We also show that under a plausible hypothesis related to the distribution of prime numbers there exist infi ..."
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Abstract. For a positive integer n let σ(n) be the sum of divisors function of n. In this note, we fix a positive integer a and we investigate the positive integers n such that na σ(n) − 1. We also show that under a plausible hypothesis related to the distribution of prime numbers there exist infinitely many positive integers n such that na σ(n) − 1 holds for all integers a coprime to n.