TY - GEN
T1 - Efficient dynamic-resharing “verifiable secret sharing” against mobile adversary
AU - Alon, Noga
AU - Galil, Zvi
AU - Yung, Moti
N1 - Publisher Copyright:
© Springer-Verlag Berlin Heidelberg 1995.
PY - 1995
Y1 - 1995
N2 - We present the notion of "Dynamic Re-sharing Verifiable Secret Sharing" (VSS) where the dealing of shares is dynamically and randomly refreshed (without changing or corrupting the secret). It works against the threat of the recently considered mobile adversary that may control all the trustees, but only a bounded number thereof at any time period. VSS enables a dealer to distribute its secret to a set of trustees, so that they are assured that the sharing is vMid and that they can open it later, and further no small group of trustees can open it prematurely. Recently, such sharing of cryptographic tools gained much attention, e.g., in the context of "key escrow cryptography;' where a user enables a group of trustees to potentially open its information (when authorized by the Court). Our dynamic-sharing VSS allows for mobile adversary attacking different sets of trustees at different time periods (modeling, e.g., network viruses that get spread as well as get elinlinated). Technically, we concentrate on simple direct methods that are conlbinatorim and number-theoretic in nature, and employ only simple public-key functions. (All previous schemes withstanding linear number of faults embedded secrets in polynomials which we do not do). In addition, our protocols are constant round. The work is a sequence of reductions. We reduce t(t < n(1/2-ε)) out-of n VSS from n out-of n one (assuming ex-or honmmorphic encryption), then we reduce dynamic resharing (by th e dealer) VSS from the static VSS, finally we reduce proactive VSS (dynamic VSS with no dealer presence after the initial sharing) from our dynamic resharing VSS.
AB - We present the notion of "Dynamic Re-sharing Verifiable Secret Sharing" (VSS) where the dealing of shares is dynamically and randomly refreshed (without changing or corrupting the secret). It works against the threat of the recently considered mobile adversary that may control all the trustees, but only a bounded number thereof at any time period. VSS enables a dealer to distribute its secret to a set of trustees, so that they are assured that the sharing is vMid and that they can open it later, and further no small group of trustees can open it prematurely. Recently, such sharing of cryptographic tools gained much attention, e.g., in the context of "key escrow cryptography;' where a user enables a group of trustees to potentially open its information (when authorized by the Court). Our dynamic-sharing VSS allows for mobile adversary attacking different sets of trustees at different time periods (modeling, e.g., network viruses that get spread as well as get elinlinated). Technically, we concentrate on simple direct methods that are conlbinatorim and number-theoretic in nature, and employ only simple public-key functions. (All previous schemes withstanding linear number of faults embedded secrets in polynomials which we do not do). In addition, our protocols are constant round. The work is a sequence of reductions. We reduce t(t < n(1/2-ε)) out-of n VSS from n out-of n one (assuming ex-or honmmorphic encryption), then we reduce dynamic resharing (by th e dealer) VSS from the static VSS, finally we reduce proactive VSS (dynamic VSS with no dealer presence after the initial sharing) from our dynamic resharing VSS.
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U2 - 10.1007/3-540-60313-1_168
DO - 10.1007/3-540-60313-1_168
M3 - Conference contribution
AN - SCOPUS:84947770625
SN - 3540603131
SN - 9783540603139
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 523
EP - 537
BT - Algorithms - ESA 1995 - 3rd Annual European Symposium, Proceedings
A2 - Spirakis, Paul
PB - Springer Verlag
T2 - 3rd Annual European Symposium on Algorithms, ESA 1995
Y2 - 25 September 1995 through 27 September 1995
ER -