CONTENTS - Emerald

041817 `How to Simultaneously Exchange Secrets by General Assumptions'
TOkamoto, K Ohta, Fairfax 94 pp 184{192
Existing secret exchange schemes assume either a speci c number theoretic primitive
or a uniformly secure bit commitment function. The authors show that these
assumptions can be weakened to the existence of one-way functions and one-way permutations.
041818 `Robust Sharing of Secrets when the Dealer is Honest or Cheating'
T Rabin, Journal of the ACM v 41 no 6 (Nov 94) pp 1089{1109
When broadcasting is permitted, the Ben-Or bound on veri able secret sharing
(that up to (n , 1)=3 players can be dishonest) is cut to (n , 1)=2. A new tool called
information checking is introduced, as is a new, weaker, form of secret sharing in which
a dishonest dealer can prevent the reconstruction of the secret.
041819 `Combinatorial Structure of A-codes with r-fold Security'
R Safavi-Naini, L Tombak, Asiacrypt 94 pp 172{184
The authors study A-codes that provide r-fold protection for spoo ng of order r. It
is shown that codes with secrecy correspond to t-designs, while codes without secrecy
correspond to orthogonal arrays. This generalises previous results since restrictions on
the minimality of the number of encoding rules and on the uniformity of the source are
removed (the latter only in the case with secrecy). The authors derive explicit bounds
on the number of encoding rules for r 2 based on Delsarte's linear programming
bound, and construct A-codes from some error-correcting codes.
041820 `Perfect authenticity and optimal A-codes'
R Safavi-Naini, L Tombak, J Pieprzyk, ISITA 94 pp 235{238
This paper introduces the notion of perfect authenticity in the context of unconditionally
secure authentication systems, and shows that such systems require manykeys;
the result is very similar to the key requirement in systems with perfect secrecy. The
paper also includes a characterisation theorem for optimal A-codes which are de ned
as A-codes with best possible protection and satisfying information theoretic bounds.
041821 `Polynomial Time Algorithms for Discrete Logarithms and Factoring
on a Quantum Computer'
PW Shor, ANTS 94 p 289
The author announces Las Vegas algorithms for discrete logarithm and factoring
which run in random polynomial time on a quantum computer.
041822 `Authentication Codes that are r-fold Secure Against Spoo ng'
LTombak, R Safavi-Naini, Fairfax 94 pp 166{169
The authors give an improved lower bound on the number of encoding rules for
authentication codes that are r-fold secure against spoo ng, and characterise the case
with a minimum number of encoding rules. This extends Stinson's characterization by
removing the condition of uniform source distribution. It is shown that if the rth order
statistic of the source is uniform, r-fold security against spoo ng follows from perfect
protection of order r.
041823 `On the Construction of Authentication and Secrecy Codes'
TV Trung, Designs, Codes and Cryptography v 5 no 3 (May 95) pp 269{280
The author presents recursive constructions for A-codes based on t-designs and on
Stinson's authentication perpendicular arrays, and gives a table of known codes.
041824 `Coding theorem for the protection of parameter estimation in
Shannon cipher system'
HYamamoto, JW-ISC 95 pp 61{65
This paper examines the coding problem for the Shannon cipher system with a
compound source.
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