Security protocols involving the use of poorly chosen secrets, usually low-entropy user passwords, are vulnerable to guessing attacks. Here, a penetrator guesses a value in place of the poorly chosen secret and then tries to verify the guess using other information. In this paper we develop a new framework extending strand space theory in the context of these attacks to analyze the effect using...

Recently, Tsai et al., Liao et al. and Li et al. each proposed a multi-server authentication protocol. They claimed their protocols are secure and can withstand various attacks. However, we found some security loopholes in each of their schemes, for example, both Tsai et al.’s and Liao et al.‘s schemes suffers from server spoofing attack by an insider server. Li et al.s’ suffers from the lost s...

Numerous recent papers (including many NIPS papers) focus on standard recurrent nets' inability to deal with long time lags between relevant input signals and teacher signals. Rather sophisticated, alternative methods were proposed. We rst show: problems used to promote certain algorithms in numerous previous papers can be solved more quickly by random weight guessing than by the proposed algor...

The notion of stationary reflection is one of the most important notions of combinatorial set theory. We investigate weak reflection, which is, as the name suggests, a weak version of stationary reflection. This sort of reflection was introduced in [DjSh 545], where it was shown that weak reflection has applications to various guessing principles, in the sense that if there is no weak reflectio...