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In 2016, Karney proposed an exact sampling algorithm for the standard normal distribution. In this paper, we study the computational complexity of this algorithm under the random deviate model. Specifically, Karney's algorithm requires the access to an infinite sequence of independently and uniformly random deviates over the range (0, 1). We give a theoretical estimate of the expected number of uniform deviates used by this algorithm until it completes, and present an improved algorithm with lower uniform deviate consumption. The experimental results also shows that our improved algorithm has better performance than Karney's algorithm. [ABSTRACT FROM AUTHOR]

Strong designated verifier signature (SDVS) provides secret authentication service to entities in a computing task. The primitive assures that an entity’s signature is verified only by a designated service provider. It also assures that a transcript about a computing task can be produced by both the entity and its service provider independently. Then neither can prove to a third party that an entity is involved in a task. Currently, most SDVS schemes without random oracles have no strong unforgeability and privacy of signer’s identity. This paper proposes a systematic method to design SDVS schemes without random oracles. It provides a basic scheme with unforgeability and non-transferability properties. Then provides it an SDVS scheme with strong unforgeability and privacy of signer’s identity properties and based on standard assumptions. Finally, a more efficient SDVS scheme is shown based on a non-black box assumption. [ABSTRACT FROM AUTHOR]

This paper gives definitions, constructions and applications of signature schemes, which are selectively unforgeable but existentially forgeable (SUEF). We formalize the special notion under conditions of chosen message attack (CMA) and known message attack (KMA). Then two general constructions are presented with two concrete examples. We apply the SUEF secure signature schemes to an elementary authentication mechanism, the challenge-response mechanism, to obtain a basic deniable authentication method. The method is presented as a deniable message transmission (MT) authenticator in the extension framework of Raimondo. [ABSTRACT FROM AUTHOR]

Proxy signatures have been used to enable the transfer of digital signing power within some context and ring signatures can be used to provide the anonymity of a signer. By combining the functionalities of proxy signatures and ring signatures, this paper introduces a new concept, named ring proxy signature, which is a proxy signature generated by an anonymous member from a set of potential signers. The paper also constructs the first concrete ring proxy signature scheme based on the provably secure Schnorr’s signatures and two ID-based ring proxy signature schemes. The security analysis is provided as well. [ABSTRACT FROM AUTHOR]

The famous Square attacks against the Rijndael algorithm have taken advantage of the change of the balance of some bytes. Further study shows that the change of activity always happens before the change of balance, which builds the foundation for a new activity attack presented in this paper. In the activity attack, the round in which the activity changes is executed in an equivalent form to avoid the obstructive restriction of the subkeys of that round. The existence of the birthday paradox guarantees much fewer plaintexts necessary for activity attacks comparing with that for corresponding Square attacks. But no benefit may result from the new attacks performed independently because the activity attacks guess four instead of one key byte once. Only when both the balance property and the activity property are exploited at the same time can much better performance be obtained. The better performance in the simulation shows that the consuming time and chosen plaintexts necessary are both reduced to one tenth of those of the corresponding Square attacks. So the activity attacks could be viewed as an efficient supplement to the Square attacks. [ABSTRACT FROM AUTHOR]

The autocorrelation of a Boolean function possesses the capability to reflect such characteristics as linear structure, Strict Avalanche Criterion(SAC) and Propagation Criterion(PC) of degree k. But it can do nothing in determining the order of SAC or PC. A calculating table for the autocorrelation is constructed in this paper so as to show what is beyond the autocorrelation and how the three cryptographic characteristics are exhibited. A deeper study on the calculating table in a similar way has helped us to develop a new concept, named as the general autocorrelation, to address efficiently the problem how to determine the orders of SAC and PC. The application on the Advanced Encryption Standard(AES) shows the SAC and PC characteristics of Boolean functions of AES S-box. [ABSTRACT FROM AUTHOR]