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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.


Papers
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Proceedings ArticleDOI
11 Nov 2019
TL;DR: OAuthGuard as mentioned in this paper is an OAuth 2.0 and OpenID Connect vulnerability scanner and protector, which works with RPs using Google OAuth2.0/OpenID Connect services.
Abstract: Millions of users routinely use Google to log in to websites supporting the standardised protocols OAuth 2.0 or OpenID Connect; the security of OAuth 2.0 and OpenID Connect is therefore of critical importance. As revealed in previous studies, in practice RPs often implement OAuth 2.0 incorrectly, and so many real-world OAuth 2.0 and OpenID Connect systems are vulnerable to attack. However, users of such flawed systems are typically unaware of these issues, and so are at risk of attacks which could result in unauthorised access to the victim user's account at an RP. In order to address this threat, we have developed OAuthGuard, an OAuth 2.0 and OpenID Connect vulnerability scanner and protector, that works with RPs using Google OAuth 2.0 and OpenID Connect services. It protects user security and privacy even when RPs do not implement OAuth 2.0 or OpenID Connect correctly. We used OAuthGuard to survey the 1000 top-ranked websites supporting Google sign-in for the possible presence of five OAuth 2.0 or OpenID Connect security and privacy vulnerabilities, of which one has not previously been described in the literature. Of the 137 sites in our study that employ Google Sign-in, 69 were found to suffer from at least one serious vulnerability. OAuthGuard was able to protect user security and privacy for 56 of these 69 RPs, and for the other 13 was able to warn users that they were using an insecure implementation.

11 citations

Book ChapterDOI
01 Jan 2011
TL;DR: This work proposes a novel scheme to provide interoperability between two of the most widely discussed identity management systems, namely CardSpace and OpenID, based on a browser extension.
Abstract: We propose a novel scheme to provide interoperability between two of the most widely discussed identity management systems, namely CardSpace and OpenID. In this scheme, CardSpace users are able to obtain an assertion token from an OpenID-enabled identity provider, the contents of which can be processed by a CardSpace-enabled relying party. The scheme, based on a browser extension, is transparent to OpenID providers and to the CardSpace identity selector, and only requires minor changes to the operation of the CardSpace relying party.

11 citations

Journal ArticleDOI
TL;DR: A direct measure of associative strength, identification of the outcome with which a cause was paired, was used to see whether associated strength translated directly into causal ratings, and results support an inferential over an associative account of causal judgments.
Abstract: It has been suggested that causal learning in humans is similar to Pavlovian conditioning in animals. According to this view, judgments of cause reflect the degree to which an association exists between the cause and the effect. Inferential accounts, by contrast, suggest that causal judgments are reasoning based rather than associative in nature. We used a direct measure of associative strength, identification of the outcome with which a cause was paired (cued recall), to see whether associative strength translated directly into causal ratings. Causal compounds AB+ and CD+ were intermixed with A+ and C- training. Cued-recall performance was better for cue B than for cue D; thus, associative strength was inherited by cue B from the strongly associated cue A (augmentation). However, the reverse was observed on the causal judgment measure: Cue B was judged to be less causal than D (cue competition). These results support an inferential over an associative account of causal judgments.

11 citations

Journal ArticleDOI
TL;DR: The results of interpolating AB+ between A+ and AB++ training were consistent with the hypothesis that pretraining with Cue A selectively suppressed attention to its associate across the AB+ trials and, thereby, reduced the amount subsequently learned about B on AB++ trials.
Abstract: A series of experiments studied the amount learned about two food cues (A and B) whose presentation in a meal was followed by an allergy () in a fictitious patient. Participants were trained with A and C in Phase 1 and then with AB or AB in Phase 2. Subsequent testing revealed that BC was more allergenic than AD, showing that more had been learned about B than A in Phase 2. Participants were also trained with A, then with AB, and finally with AB. The results of interpolating AB between A and AB training were consistent with the hypothesis that pretraining with Cue A selectively suppressed attention to its associate across the AB trials and, thereby, reduced the amount subsequently learned about B on AB trials. Kamin (1969) reported a failure of Pavlovian conditioning termed the "blocking" phenomenon that has been influential in the development of models of associative learning. Two groups of rats received presentations of a compound stimulus composed of a light and noise followed by a brief foot shock. Subsequently, rats were tested with one of the elements of the compound (e.g., the light). The difference between the groups was that rats in one group had received pairings of the noise and shock in advance of the compound-shock pairings. The rats not pretrained with the noise showed fear reactions when tested with the light, but the rats pretrained with the noise showed little if any fear reaction to the light. The pretrained noise was said to have blocked learning about the light across the otherwise effective compound conditioning trials. The blocking phenomenon has been well documented across various conditioned stimuli (CSs) with the use of both aversive and appetitive unconditioned stimuli (USs) in a range of animal sub- jects. It has also been observed in human causal learning para- digms (De Houwer, Beckers, & Glautier, 2002; Esmoris-Arranz, Miller, & Matute, 1997; Le Pelley, Oakeshott, & McLaren, 2004; Lovibond, Been, Mitchell, Bouton, & Frohardt, 2003). Models of associative learning explain blocking in two ways. One, exemplified by the Rescorla-Wagner model (Rescorla & Wagner, 1972), attributes blocking of the added stimulus (CS B) to a decline in the effectiveness of the US because its occurrence is already predicted by the pretrained stimulus (CS A). Formally, learning is limited by the summed associative strength of all CSs present on a given trial, according to the equation:

11 citations

Journal ArticleDOI
TL;DR: This response provides further clarification of the propositional approach to human associative learning and challenges proponents of dual-system models to specify the systems more clearly so that these models can be tested.
Abstract: In this response, we provide further clarification of the propositional approach to human associative learning. We explain why the empirical evidence favors the propositional approach over a dual-system approach and how the propositional approach is compatible with evolution and neuroscience. Finally, we point out aspects of the propositional approach that need further development and challenge proponents of dual-system models to specify the systems more clearly so that these models can be tested.

10 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
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 …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组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�ly.
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。

18,940 citations

Book
01 Jan 1996
TL;DR: 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.
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.

13,597 citations

Journal ArticleDOI
23 Jan 2015-Science
TL;DR: In this paper, 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.
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.

9,745 citations

Book ChapterDOI
15 Aug 1999
TL;DR: In this paper, the authors examine specific methods for analyzing power consumption measurements to find secret keys from tamper resistant devices. And they also discuss approaches for building cryptosystems that can operate securely in existing hardware that leaks information.
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.

6,757 citations