The only known construction of key-insulated signature(KIS) that can be proven secure in the standard model is based on the approach of using double signing. That is,the scheme requires two signatures:a signature with a master key and a signature with the signer's secret key. This folklore construction method leads to an ineffcient scheme. Therefore it is desirable to devise an effcient KIS scheme. We present the first scheme with such a construction. Our construction derives from some variations of the Waters' signature scheme. It is computationally effcient and the signatures are short. The scheme is provably secure based on the diffculty of computational Diffe-Hellman(CDH) problem in the standard model.
This paper presents a DNA algorithm based on linear self-assembly which gives the result of the modular subtraction operation of two nonnegative integers.For two n-bit nonnegative integers A and B,the algorithm gives the result of A-B mod 2 n.An extended borrow tag which indicates the relation of the minuend and the subtrahend is included in the resulting strand so that the pre-classification based on A>B or B>A is not required before the experiment.From the resulting strand,we can draw the information of operation result,operands,borrow,and the tag of the relation between the minuend and the subtrahend.The algorithm takes advantage of the parallelism characteristic of DNA computing:while given two sets of operands (one the minuend set and the other subtrahend set),the modular subtraction operation of these two sets can be achieved by a parallel processing procedure.The feasibility of the algorithm is based on a known experiment.The algorithm is of spontaneous characteristic which prevents the scale of the experimental procedures from growing with the length of the operands.As for the length of the operands n,there are O(n) kinds of strands required in the experiment,and the biochemical experimental procedures can be accomplished in constant number of steps.
