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### Quadratic Time Algorithms Appear to be Optimal for Sorting Evolving Data [chapter]

Juan José Besa Vial, William E. Devanny, David Eppstein, Michael T. Goodrich, Timothy Johnson
2018 2018 Proceedings of the Twentieth Workshop on Algorithm Engineering and Experiments (ALENEX)
In this model, a sorting algorithm maintains an approximation to the sorted order of a list of data items while simultaneously, with each comparison made by the algorithm, an adversary randomly swaps the  ...  Previous work studies only two versions of quicksort, and has a gap between the lower bound of Ω(n) and the best upper bound of O(n log log n).  ...  During each time step, a sorting algorithm is allowed to perform one comparison of a pair of elements and then an adversary is allowed to perform some random swaps between adjacent elements in the true  ...

### A killer adversary for quicksort

M. D. McIlroy
1999 Software, Practice & Experience
This note describes an adversarial method that finds chinks in the defenses of any implementation.  ...  To do so we make a comparison function that observes the pattern of comparisons and constructs adverse data on the fly. Recall that quicksort sorts a sequence of n data items in three phases:  ...  The Appendix shows an adversary for C's qsort. The function antiqsort(n, a) constructs in array a a bad permutation of 0..n − 1 and returns the number of comparisons qsort took to sort it.  ...

### A killer adversary for quicksort

M. D. McIlroy
1999 Software, Practice & Experience
This note describes an adversarial method that finds chinks in the defenses of any implementation.  ...  To do so we make a comparison function that observes the pattern of comparisons and constructs adverse data on the fly. Recall that quicksort sorts a sequence of n data items in three phases:  ...  The Appendix shows an adversary for C's qsort. The function antiqsort(n, a) constructs in array a a bad permutation of 0..n − 1 and returns the number of comparisons qsort took to sort it.  ...

### Maximum Selection and Sorting with Adversarial Comparators and an Application to Density Estimation [article]

Jayadev Acharya, Moein Falahatgar, Ashkan Jafarpour, Alon Orlitsky, Ananda Theertha Suresh
2016 arXiv   pre-print
We study maximum selection and sorting of \$n\$ numbers using pairwise comparators that output the larger of their two inputs if the inputs are more than a given threshold apart, and output an adversarially-chosen  ...  A non-adaptive adversary that decides on the outcomes in advance based solely on the inputs, and an adaptive adversary that can decide on the outcome of each query depending on previous queries and outcomes  ...  Acknowledgment We thank Jelani Nelson for introducing us to the problem's adaptive adversarial model.  ...

### Ptolemy: Architecture Support for Robust Deep Learning [article]

Yiming Gan, Yuxian Qiu, Jingwen Leng, Minyi Guo, Yuhao Zhu
2020 arXiv   pre-print
imperative program execution: an input to a DNN uniquely activates a set of neurons that contribute significantly to the inference output, analogous to the sequence of basic blocks exercised by an input  ...  Critically, we observe that adversarial samples tend to activate distinctive paths from those of benign inputs.  ...  Jingwen Leng and Minyi Guo are the corresponding authors of the paper.  ...

### Enrich-by-need Protocol Analysis for Diffie-Hellman (Extended Version) [article]

Moses D. Liskov and Joshua D. Guttman and John D. Ramsdell and Paul D. Rowe and F. Javier Thayer
2018 arXiv   pre-print
Enrich-by-need protocol analysis is a style of symbolic protocol analysis that characterizes all executions of a protocol that extend a given scenario.  ...  An appendix explains how unification is efficiently done in our framework.  ...  Given a protocol Π, an execution of Π with an active adversary is a bundle in which every strand represents either an initial part of a local run of some role in Π, or else some adversary activity.  ...

### Sorting with adversarial comparators and application to density estimation

Jayadev Acharya, Ashkan Jafarpour, Alon Orlitsky, Ananda Theertha Suresh
2014 2014 IEEE International Symposium on Information Theory
We consider the problems of sorting and maximumselection of n elements using adversarial comparators.  ...  Our adversarial-comparator model was motivated by the practically important problem of density-estimation, where we observe samples from an unknown distribution, and try to determine which of n known distributions  ...  In the case of arbitrary output in Equation (2) , we allow an adversary to choose the output.  ...

### On Adversarial Robustness of 3D Point Cloud Classification under Adaptive Attacks [article]

Jiachen Sun, Karl Koenig, Yulong Cao, Qi Alfred Chen, Z. Morley Mao
2021 arXiv   pre-print
Though a few defenses against adversarial point cloud classification have been proposed, it remains unknown whether they are truly robust to adaptive attacks.  ...  To this end, we perform the first security analysis of state-of-the-art defenses and design adaptive evaluations on them.  ...  Attention-based Pooling Operations An attention module can be abstracted as mapping a query and a set of key-value pairs to an output, making the models learn and focus on the critical information [4]  ...

### Batched Predecessor and Sorting with Size-Priced Information in External Memory [article]

Michael A. Bender, Mayank Goswami, Dzejla Mededovic, Pablo Montes, Kostas Tsichlas
2020 arXiv   pre-print
The cost to compare two items in \$A\$ is \$a\$, to compare an item of \$A\$ to an item of \$B\$ is \$b\$, and to compare two items in \$B\$ is \$c\$. We give upper and lower bounds for the case \$a \le b \le c\$.  ...  In the unit-cost comparison model, a black box takes an input two items and outputs the result of the comparison.  ...  Consider an external-memory algorithm A that sorts the total volume V of V /w elements, each of size w. 1. If 1 ≤ w < B, A requires Ω V B log M/B V B block transfers. 2.  ...

### A composable computational soundness notion

Veronique Cortier, Bogdan Warinschi
2011 Proceedings of the 18th ACM conference on Computer and communications security - CCS '11
However, a key aspect of deduction soundness is that it considers, intrinsically, the use of the primitives in the presence of functions specified by the adversary.  ...  As for other soundness notions, our definition captures the idea that a computational adversary does not have any more power than a symbolic adversary.  ...  In particular, Dominique suggested the search for a modular way of proving the commutation property. This work has been supported in part by the European  ...

Hongying Liu, Zhenyu Zhou, Fanhua Shang, Xiaoyu Qi, Yuanyuan Liu, Licheng Jiao
2020 arXiv   pre-print
Therefore, we propose a universal adversarial example generation method, called ADV-ReLU, to enhance the performance of gradient based white-box attack algorithms.  ...  However, a growing number of studies have shown that there exist adversarial examples in DNNs, which are almost imperceptibly different from original samples, but can greatly change the network output.  ...  x is an adversarial example.  ...

### Simple Black-Box Adversarial Attacks on Deep Neural Networks

Nina Narodytska, Shiva Kasiviswanathan
2017 2017 IEEE Conference on Computer Vision and Pattern Recognition Workshops (CVPRW)
Our attacks utilize a novel local-search based technique to construct numerical approximation to the network gradient, which is then carefully used to construct a small set of pixels in an image to perturb  ...  Our attacks treat the network as an oracle (black-box) and only assume that the output of the network can be observed on the probed inputs.  ...  From sorted(I), it records a set of pixel locations (P * X , P * Y ) i based on the first t elements of sorted(I), where the parameter t regulates the number of pixels perturbed in each round.  ...

### SGX-MR: Regulating Dataflows for Protecting Access Patterns of Data-Intensive SGX Applications [article]

A K M Mubashwir Alam, Sagar Sharma, Keke Chen
2020 arXiv   pre-print
However, the access patterns of SGX-based programs can still be observed by adversaries, which may leak important information for successful attacks.  ...  It uses the MapReduce framework to cover a large class of data-intensive applications, and the entire framework can be implemented with a small memory footprint.  ...  We apply an additional bitonic sorting over the padded blocks and extract top-k elements to get rid of the dummy records, so that the group size ranking is still oblivious to adversaries.  ...

### Consensus in networked multi-agent systems with adversaries

Heath J. LeBlanc, Xenofon D. Koutsoukos
2011 Proceedings of the 14th international conference on Hybrid systems: computation and control - HSCC '11
Finally, we illustrate the resilience of ARC-P to adversaries through simulations and compare ARC-P with a linear consensus protocol for networked multi-agent systems.  ...  In this work, we consider a general model for adversaries in Euclidean space and introduce a consensus problem for networked multi-agent systems similar to the Byzantine consensus problem in distributed  ...  The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the  ...

### Secure Multi-party Shuffling [chapter]

Mahnush Movahedi, Jared Saia, Mahdi Zamani
2015 Lecture Notes in Computer Science
In secure multi-party shuffling, multiple parties, each holding an input, want to agree on a random permutation of their inputs while keeping the permutation secret.  ...  In particular, we require each party to send only a polylogarithmic number of bits and perform a polylogarithmic number of operations while incurring only a logarithmic round complexity.  ...  valuable comments from Ran Canetti (Boston University), Bryan Ford (Yale University), Shafi Goldwasser (MIT), Aniket Kate (Purdue University), Yehuda Lindell (Bar-Ilan University), and anonymous reviewers of  ...
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