Chris J. Mitchell

Bio: Chris J. Mitchell is an academic researcher from Royal Holloway, University of London. The author has contributed to research in topics: Authentication & Cryptography. The author has an hindex of 48, co-authored 397 publications receiving 10982 citations. Previous affiliations of Chris J. Mitchell include Johns Hopkins University & University of Portland.

Dynamic content attacks on digital signatures

Abstract: Purpose – Aims to address some of the problems that arise when signing digital documents that contain dynamic content.Design/methodology/approach – Briefly introduces the problem of signing digital documents with dynamic content and discusses possible locations for signature functionality in a computer system. Outlines existing solutions to the problems and introduces a novel solution. Finally, discusses issues and unresolved problems.Findings – The suggested solution requires all document handling applications to possess application awareness of the digital signature program in order to function properly. Every application must implement a COM interface and register itself in the Registry, in a locale specific to the digital signature program to sign the digital document.Originality/value – Provides a new solution to the problem of digitally signing a digital document.

Digital rights management using a mobile phone

Abstract: This paper focuses on the problem of preventing illegal copying of digital assets without jeopardising the right of legitimate licence holders to transfer content between their own devices, which make up a domain. Our novel idea involves the use of a domain-specific mobile phone and the mobile phone network operator to authenticate the domain owner before devices can join a domain. This binds devices in a domain to a single owner, that, in turn, enables the binding of domain licences to the domain owner. In addition, the way in which we control domain membership, and the use of the domain-specific mobile phone that enables a domain owner to add devices wherever he/she is physically present, ensures that devices joining the domain are in physical proximity to the mobile phone, preventing illicit content proliferation.

Trashing IMSI catchers in mobile networks

Abstract: We address the decades-old privacy problem of disclosure of the permanent subscriber identity (IMSI) that makes IMSI catchers a real threat to all generations of mobile networks. A number of possible modifications to existing protocols have been proposed to address the problem; however, most require significant changes to existing deployed infrastructures. We propose a novel authentication approach for 3G and 4G systems that does not affect intermediate entities, notably the serving network and mobile equipment. It prevents disclosure of the subscriber's IMSI by using a dynamic pseudo-IMSI that is only identifiable by the home network for the USIM. A major challenge in using dynamic pseudo-IMSIs is possible loss of identity synchronisation between USIM and home network, an issue that has not been adequately addressed in previous work. We present an approach for identity recovery to be used in the event of pseudo-IMSI desynchronisation. The scheme requires changes to the home network and the USIM, but not to the serving network, mobile phone or other internal network protocols, enabling simple, transparent and evolutionary migration. We provide a detailed analysis of the scheme, and verify its correctness and security properties using ProVerif.

Fixing a problem in the Helsinki protocol

Abstract: We consider a recently described attack on a key establishment protocol contained in a draft international standard. Based on an observation as to why the attack is possible, we propose a simple modification to the protocol which avoids the attack.

Supporting User Privacy in Location Based Services

Abstract: To offer location based services, service providers need to have access to Location Information (LI) regarding the users which they wish to serve; this is a potential privacy threat. We propose the use of constraints, i.e. statements limiting the use and distribution of LI, that are securely bound to the LI, as a means to reduce this threat. Constraints may themselves reveal information to any potential LI user-that is, the constraints themselves may also be a privacy threat. To address this problem we introduce the notion of a LI Preference Authority (LIPA). A LIPA is a trusted party which can examine LI constraints and make decisions about LI distribution without revealing the constraints to the entity requesting the LI. This is achieved by encrypting both the LI and the constraints with a LIPA encryption key, ensuring that the LI is only revealed at the discretion of the LIPA.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Handbook of Applied Cryptography

Abstract: From the Publisher: A valuable reference for the novice as well as for the expert who needs a wider scope of coverage within the area of cryptography, this book provides easy and rapid access of information and includes more than 200 algorithms and protocols; more than 200 tables and figures; more than 1,000 numbered definitions, facts, examples, notes, and remarks; and over 1,250 significant references, including brief comments on each paper.

Tissue-based map of the human proteome

Abstract: Resolving the molecular details of proteome variation in the different tissues and organs of the human body will greatly increase our knowledge of human biology and disease. Here, we present a map of the human tissue proteome based on an integrated omics approach that involves quantitative transcriptomics at the tissue and organ level, combined with tissue microarray-based immunohistochemistry, to achieve spatial localization of proteins down to the single-cell level. Our tissue-based analysis detected more than 90% of the putative protein-coding genes. We used this approach to explore the human secretome, the membrane proteome, the druggable proteome, the cancer proteome, and the metabolic functions in 32 different tissues and organs. All the data are integrated in an interactive Web-based database that allows exploration of individual proteins, as well as navigation of global expression patterns, in all major tissues and organs in the human body.

Differential Power Analysis

Abstract: Cryptosystem designers frequently assume that secrets will be manipulated in closed, reliable computing environments. Unfortunately, actual computers and microchips leak information about the operations they process. This paper examines specific methods for analyzing power consumption measurements to find secret keys from tamper resistant devices. We also discuss approaches for building cryptosystems that can operate securely in existing hardware that leaks information.