To provide secure authentication for wireless sensor networks (WSNs), recently Jiang et al. proposed an efficient two-factor user authentication scheme with unlinkability. They argued that the scheme provides resilience of privileged insider attack, stolen-verifier attack, password guessing attack, weak stolen smart card attack, replay attack, forgery attack, identity guessing attack and tracki...

In 2010, Yeh et al. proposed two robust remote user authentication schemes using smart cards; their claims were such that their schemes defended against ID-theft attacks, reply attacks, undetectable on-line password guessing attacks, off-line password guessing attacks, user impersonation attack, server counterfeit attack and man-in-the-middle attack. In this paper, we show that Yeh et al.’s sch...

We give two results on guessing unbounded subsets of λ+. The first is a positive result and applies to the situation of λ regular and at least equal to א3, while the second is a negative consistency result which applies to the situation of λ a singular strong limit with 2 > λ+. The first result shows that in ZFC there is a guessing of unbounded subsets of S + λ . The second result is a consiste...

In this paper we demonstrate how to use Mixed Integer Linear Programming to optimize guessing strategies for algebraic cryptanalysis with applications to the block cipher EPCBC. Using our optimized guessing strategy we are able to attack 5 rounds of EPCBC96 and 8 rounds of EPCBC-48 faster than brute force using one and two known plaintexts resp. Finally, we are able to identify a class of weak ...

Scoring methods in multiple−choice tests are usually designed as fair bets, and thus random guesswork yields zero expected return. This causes the undesired result of forcing risk averse test−takers to pay a premium in the sense of letting unmarked answers for which they have partial but not full knowledge. In this note I use a calibrated model of prospect theory [Tversky and Kahneman (1992, 19...

We investigate the problem of guessing a random vector X within distortion level D. Our aim is to characterize the best attainable performance in the sense of minimizing, in some probabilistic sense, the number of required guesses G(X) until the error falls below D. The underlying motivation is that G(X) is the number of candidate codewords to be examined by a rate-distortion block encoder unti...

Hat problems have become a popular topic in recreational mathematics. In a typical hat problem, each of n players tries to guess the color of the hat they are wearing by looking at the colors of the hats worn by some of the other players. In this paper we consider several variants of the problem, united by the common theme that the guessing strategies are required to be deterministic and the ob...

Given d complex numbers z1, ..., zd, it is classical that linear dependencies λ1 z1+ ···+ λd zd=0 with λ1, ..., λd∈Z can be guessed using the LLL-algorithm. Similarly, given d formal power series f1, ..., fd ∈ C[[z]], algorithms for computing Padé-Hermite forms provide a way to guess relations P1 f1 + ···+ Pd fd = 0 with P1, ..., Pd ∈C[z]. Assuming that f1, ..., fd have a radius of convergence ...

Passwords still dominate the authentication space, but they are vulnerable to many different attacks; in recent years, guessing attacks in particular have notably caused a few high-profile information leaks. Password strength checkers, which attempt to guard against guessing attacks by enforcing heuristics like length and character variety, only model resistance to these brute-force attacks by ...

Text-based passwords, dominant mechanism of authentication nowadays, are vulnerable to malicious attackers. Even though not recommended, users tend to use personal information (PI) when create passwords. Only a few studies have researched targeted password guessing, in which attackers guess passwords by utilizing users’ PI. We propose TPGXNN, a framework that uses neural networks (NN) in target...