Improved Approximation Algorithm for the Number of Queries Necessary to Identify a Permutation

In the past three decades, deductive games have become interesting from the algorithmic point of view. Deductive games are two players zero sum games of imperfect information. The first player, called "codemaker", chooses a secret code and the second player, called "codebreaker", tries to break the secret code by making as few guesses as possible, exploiting information that is given by the codemaker after each guess. A well known deductive game is the famous Mastermind game. In this paper, we consider the so called Black-Peg variant of Mastermind, where the only information concerning a guess is the number of positions in which the guess coincides with the secret code. More precisely, we deal with a special version of the Black-Peg game with n holes and k >= n colors where no repetition of colors is allowed. We present a strategy that identifies the secret code in O(n log n) queries. Our algorithm improves the previous result of Ker-I Ko and Shia-Chung Teng (1985) by almost a factor of 2 for the case k = n. To our knowledge there is no previous work dealing with the case k > n. Keywords: Mastermind; combinatorial problems; permutations; algorithm

On the Query Complexity of Black-Peg AB-Mastermind

Mastermind is a two players zero sum game of imperfect information. Starting with Erd˝os and Rényi (1963), its combinatorics have been studied to date by several authors, e.g., Knuth (1977), Chvátal (1983), Goodrich (2009). The first player, called “codemaker”, chooses a secret code and the second player, called “codebreaker”, tries to break the secret code by making as few guesses as possible, exploiting information that is given by the codemaker after each guess. For variants that allow color repetition, Doerr et al. (2016) showed optimal results. In this paper, we consider the so called Black-Peg variant of Mastermind, where the only information concerning a guess is the number of positions in which the guess coincides with the secret code. More precisely, we deal with a special version of the Black-Peg game with n holes and k ≥ n colors where no repetition of colors is allowed. We present upper and lower bounds on the number of guesses necessary to break the secret code. For the case k = n, the secret code can be algorithmically identified within less than (n − 3)dlog 2 ne + 5 2 n − 1 queries. This result improves the result of Ker-I Ko and Shia-Chung Teng (1985) by almost a factor of 2. For the case k > n, we prove an upper bound of (n − 2)dlog 2 ne + k + 1. Furthermore, we prove a new lower bound of n for the case k = n, which improves the recent n − log log(n) bound of Berger et al. (2016). We then generalize this lower bound to k queries for the case k ≥ n

Practical Padding Oracle Attacks on RSA

We revise attacks on the RSA cipher based on side-channels that leak partial information about the plaintext. We show how to compute a plaintext when only its parity is leaked. We then describe PKCS#1 v1.5 padding for RSA and we show that the simple leakage of padding errors is enough to recover the whole plaintext, even when it is unpadded or padded under another scheme. This vulnerability is well-known since 1998 but the flawed PKCS#1 v1.5 padding is still broadly in use. We discuss recent optimizations of this padding oracle attack that make it effective on commercially available cryptographic devices

Sink Hollow Volume 3

It\u27s difficult to believe that my time with this journal has come to a close. It has been one of the greatest experiences of my undergraduate career to be an integral part of its publication. At the time of this writing, our previous issues have been read over 5,500 times, with this volume set to increase that number substantially. We have worked with undergraduates across the United States and from many other countries as well. A great thanks goes out to all our submitters. Without you there is no journal. Though I\u27m moving on to other things, I trust the upcoming staff to continue in the excellent literary and aesthetic tradition which so many talented individuals have brought to life over the last two years. I have long believed, and continue to believe, in the essential function of art and literature to a healthy democracy and a healthy civilization. I am proud to have participated, in my small way, in that tradition. Ethan Trunnell, Undergraduate Edito

The BG News November 30, 1978

The BGSU campus student newspaper November 30, 1978. Volume 62 - Issue 150https://scholarworks.bgsu.edu/bg-news/4555/thumbnail.jp

Lang and Law: Analyzing Representations of Law, Justice, and Violence in the Films of Fritz Lang

This thesis analyzes the representations of Law, Justice, and Violence in the German and American films of Fritz Lang. Through an overview of legal and social unrest in Germany and courtroom drama, criminal conviction, mob violence, and police corruption in America, Lang challenges the legitimacy of Law and shows how it is subverted by outside forces. At other times, Lang shows Law working in collusion with criminal agencies or against the interests of the public. In doing this, Lang’s films present images of legal decay in the urban sphere, prompted by anxieties which come about through spatial alienation, city structure, penal institutions, and social cultures of violence. Emerging from Lang’s critique of Law is an ethical force which abides by the mechanisms of human nature, which Gunning calls the “destiny-machine.” This thesis uses Gunning’s theory of the “destiny-machine,” in conjunction with philosophical writings of Walter Benjamin to show how a critique of legal violence is shown through Lang films, as well as a correction method which presents itself through the deployment of mystical violence, taking the form of psychological instability and moral conscience in his characters. Through these forms of metaphysical violence, Lang shows images of a new future for Law, where its governing power is drawn from universal, objective moral principles of human nature, rather than the socially constructed and malleable institutions of the Law. My thesis connects these morally governing principles back to the fundamental human and religious experiences of Love

Mustang Daily, January 19, 2000

Student newspaper of California Polytechnic State University, San Luis Obispo, CA.https://digitalcommons.calpoly.edu/studentnewspaper/6529/thumbnail.jp