Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

The author systematically examines one of the important issues of information — establishing the market price. He introduces the concept of «search» — where a buyer wanting to get a better price, is forced to question sellers. The article deals with various aspects of finding the necessary information.

Economics of Information

National Institute of Standards and Technology における超伝導研究及び生活

Today’s artificial intelligence still faces two major challenges. One is that, in most industries, data exists in the form of isolated islands. The other is the strengthening of data privacy and security. We propose a possible solution to these challenges: secure federated learning. Beyond the federated-learning framework first proposed by Google in 2016, we introduce a comprehensive secure federated-learning framework, which includes horizontal federated learning, vertical federated learning, and federated transfer learning. We provide definitions, architectures, and applications for the federated-learning framework, and provide a comprehensive survey of existing works on this subject. In addition, we propose building data networks among organizations based on federated mechanisms as an effective solution to allowing knowledge to be shared without compromising user privacy.

Federated Machine Learning: Concept and Applications

The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Delay tolerant networks (DTNs) are networks whose nodes have low connectivity and/or unreliable links. Because of these characteristics, DTN nodes use a store-carry-and-forward technique to deliver data through the network. Communication over DTN relies on intermediate nodes sharing their resources and can be abused by resource hogs, i.e. individuals who generate messages at a rate that is much higher than the average. In this paper we first show that if not controlled, resource hogs can substantially reduce the proportion of successfully delivered non-hog messages. To combat this problem we propose a basic technique that utilizes coarse-grained priority classes to control resource hogs. User or node authentication can be the basis for constructing priority classes: for example, messages from certain verifiable senders are assigned to a class with higher priority. The basic technique effectively deals with strangers who act as resource hogs but cannot counter verifiable senders who exhibit resource hog behavior. We extend the basic technique into three fine-grained solutions for dealing with such "insider" hogs. We show the effectiveness of each solution in restoring message delivery ratio to the scenario where no resource hogs are present. the few who use more than their fair share of the public good will bring down the effectiveness of the system as a whole. It is natural to ask whether this problem will manifest itself in DTNs and what can be done to mitigate its implications. While infrastructure nodes are deployed specifically for this purpose (and so should be equipped with the necessary re- sources) and homogeneous sensor nodes exhibit a coherent behavior in this respect, the situation is different for devices of mobile users: they offer resources voluntarily to the ad- hoc community, and their contributions may differ vastly. To study this issue, we introduce the notion of a resource hog. A resource hog is an individual who, on the average, attempts to send through the DTN more own data, and possibly forward less of the other nodes data, than is typical for well-behaved participants.

Controlling Resource Hogs in Delay-Tolerant Networks

The security of billions of devices worldwide depends on the security and robustness of the mainline Linux kernel. However, the increasing number of kernel-specific vulnerabilities, especially memory safety vulnerabilities, shows that the kernel is a popular and practically exploitable target. Two major causes of memory safety vulnerabilities are reference counter overflows (temporal memory errors) and lack of pointer bounds checking (spatial memory errors). 
To succeed in practice, security mechanisms for critical systems like the Linux kernel must also consider performance and deployability as critical design objectives. We present and systematically analyze two such mechanisms for improving memory safety in the Linux kernel: (a) an overflow-resistant reference counter data structure designed to accommodate typical reference counter usage in kernel source code, and (b) runtime pointer bounds checking using Intel MPX in the kernel.

Towards Linux Kernel Memory Safety

Hardware Platform Security for Mobile Devices

N. Asokan Aalto University and University of Helsinki Finland asokan@acm.org

On mobile malware infections

Motivated by the great success and adoption of Bitcoin, a number of cryptocurrencies such as Litecoin, Dogecoin, and Ethereum are becoming increasingly popular. Although existing blockchain-based cryptocurrency schemes can ensure reasonable security for transactions, they do not consider any notion of fairness. Fair exchange allows two players to exchange digital "items", such as digital signatures, over insecure networks fairly, so that either each player gets the other's item, or neither player does. Given that blockchain participants typically do not trust each other, enabling fairness in existing cryptocurrencies is an essential but insufficiently explored problem. In this paper, we explore the solution space for enabling the fair exchange of a cryptocurrency payment for a receipt. We identify the timeliness of an exchange as an important property especially when one of the parties involved in the exchange is resource-constrained. We introduce the notion of strong timeliness for a fair exchange protocol and propose two fair payment-for-receipt protocol instantiations that leverage functionality of the blockchain to achieve strong timeliness. We implement both and compare their security and efficiency.

Nadarajah Asokan

Papers

Controlling Resource Hogs in Delay-Tolerant Networks

Towards Linux Kernel Memory Safety

Hardware Platform Security for Mobile Devices

On mobile malware infections

Towards Fairness of Cryptocurrency Transactions