At some point in the future, how far out we do not exactly know, wireless access to the Internet will outstrip all other forms of access bringing the freedom of mobility to the way we access the we...

ACM SIGCOMM computer communication review

Teaching has often been thought of as a creative performance. Although comparisons with performance were originally intended to emphasize teacher creativity, they have become associated instead with contemporary reform efforts toward scripted instruction that deny the creativity of teachers. Scripted instruction is opposed to constructivist, inquiry-based, and dialogic teaching methods that emphasize classroom collaboration. To provide insight into these methods, the “teaching as performance” metaphor must be modified: Teaching is improvisational performance. Conceiving of teaching as improvisation highlights the collaborative and emergent nature of effective classroom practice, helps us to understand how curriculum materials relate to classroom practice, and shows why teaching is a creative art.

Creative Teaching: Collaborative Discussion as Disciplined Improvisation

Today's technical and legal landscape presents formidable challenges to personal data privacy First, our increasing reliance on Web services causes personal data to be cached, copied, and archived by third parties, often without our knowledge or control Second, the disclosure of private data has become commonplace due to carelessness, theft, or legal actions

Our research seeks to protect the privacy of past, archived data -- such as copies of emails maintained by an email provider -- against accidental, malicious, and legal attacks Specifically, we wish to ensure that all copies of certain data become unreadable after a userspecified time, without any specific action on the part of a user, and even if an attacker obtains both a cached copy of that data and the user's cryptographic keys and passwords

This paper presents Vanish, a system that meets this challenge through a novel integration of cryptographic techniques with global-scale, P2P, distributed hash tables (DHTs) We implemented a proof-of-concept Vanish prototype to use both the million-plus-node Vuze Bit-Torrent DHT and the restricted-membership OpenDHT We evaluate experimentally and analytically the functionality, security, and performance properties of Vanish, demonstrating that it is practical to use and meets the privacy-preserving goals described above We also describe two applications that we prototyped on Vanish: a Firefox plugin for Gmail and other Web sites and a Vanishing File application

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Vanish: increasing data privacy with self-destructing data

As the Internet's de facto interdomain routing protocol, the Border Gateway Protocol (BGP) is the glue that holds the disparate parts of the Internet together. A major limitation of BGP is its failure to adequately address security. Recent high-profile outages and security analyses clearly indicate that the Internet routing infrastructure is highly vulnerable. Moreover, the design of BGP and the ubiquity of its deployment have frustrated past efforts at securing interdomain routing. This paper considers the current vulnerabilities of the interdomain routing system and surveys both research and standardization efforts relating to BGP security. We explore the limitations and advantages of proposed security extensions to BGP, and explain why no solution has yet struck an adequate balance between comprehensive security and deployment cost.

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A Survey of BGP Security Issues and Solutions

Recent technologies have cleared the way for large scale application of electronic communication. The open and distributed nature of these communications implies that the communication medium is no longer completely controlled by the communicating parties. As a result, there has been an increasing demand for research in establishing secure communications over insecure networks, by means of security protocols. In this thesis, a formal model for the description and analysis of security protocols at the process level is developed. At this level, under the assumption of perfect cryptography, the analysis focusses on detecting aws and vulnerabilities of the security protocol. Starting from ??rst principles, operational semantics are developed to describe security protocols and their behaviour. The resulting model is parameterized, and can e.g. capture various intruder models, ranging from a secure network with no intruder, to the strongest intruder model known in literature. Within the security protocol model various security properties are de??ned, such as secrecy and various forms of authentication. A number of new results about these properties are formulated and proven correct. Based on the model, an automated veri??cation procedure is developed, which signi ??cantly improves over existing methods. The procedure is implemented in a prototype, which outperforms other tools. Both the theory and tool are applied in two novel case studies. Using the tool prototype, new results are established in the area of protocol composition, leading to the discovery of a class of previously undetected attacks. Furthermore, a new protocol in the area of multiparty authentication is developed. The resulting protocol is proven correct within the framework.

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Scyther : semantics and verification of security protocols

Recent studies have highlighted user concerns with respect to third-party tracking and online behavioral advertising (OBA) and the need for better consumer choice mechanisms to address these phenomena. We re-investigate the question of perceptions of third-party tracking while situating it in the larger context of how online ads, in general, are perceived by users. Via in-depth interviews with 53 Web users in India, we find that although concerns for third-party tracking and OBA remain noticeable amongst this population, other aspects of online advertising---like the possibility of being shown ads with embarrassing and suggestive content---are voiced as greater concerns than the concern of being tracked. Current-day blocking tools are insufficient to redress the situation: users demand selective filtering of ad content (as opposed to blocking out all ads) and are not satisfied with mechanisms that only control tracking and OBA. We conclude with design recommendations for enduser tools to control online ad consumption keeping in mind the concerns brought forth by our study.

/pdf/do-not-embarrass-re-examining-user-concerns-for-online-43cdrc07ug.pdf

Do not embarrass: re-examining user concerns for online tracking and advertising

We present a new primitive – Append-only Signatures (AOS) – with the property that any party given an AOS signature Sig[M1] on message M1 can compute Sig[M1 || M2] for any message M2, where M1 || M2 is the concatenation of M1 and M2. We define the security of AOS, present concrete AOS schemes, and prove their security under standard assumptions. In addition, we find that despite its simple definition, AOS is equivalent to Hierarchical Identity-based Signatures (HIBS) through efficient and security-preserving reductions. Finally, we show direct applications of AOS to problems in network security. Our investigations indicate that AOS is both useful in practical applications and worthy of further study as a cryptographic primitive.

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Append-only signatures

We prove a computational soundness theorem for the symbolic analysis of cryptographic protocols which extends an analogous theorem of Abadi and Rogaway (J. of Cryptology 15(2):103–127, 2002) to a scenario where the adversary gets to see the encryption of a sequence of adaptively chosen symbolic expressions. The extension of the theorem of Abadi and Rogaway to such an adaptive scenario is nontrivial, and raises issues related to the classic problem of selective decommitment, which do not appear in the original formulation of the theorem.

Although the theorem of Abadi and Rogaway applies only to passive adversaries, our extension to adaptive attacks makes it substantially stronger, and powerful enough to analyze the security of cryptographic protocols of practical interest. We exemplify the use of our soundness theorem in the analysis of group key distribution protocols like those that arise in multicast and broadcast applications. Specifically, we provide cryptographic definitions of security for multicast key distribution protocols both in the symbolic as well as the computational framework and use our theorem to prove soundness of the symbolic definition.

/pdf/adaptive-security-of-symbolic-encryption-1picnrcxlb.pdf

Adaptive security of symbolic encryption

This paper explores user authentication schemes for banking systems implemented over mobile phone networks in the developing world. We analyze an authentication scheme currently deployed by an Indian mobile banking service provider which uses a combination of PINs and printed codebooks for authenticating users. As a first step, we report security weaknesses in that scheme and show that it is susceptible to easy and efficient PIN recovery attacks. We then propose a new scheme which offers better secrecy of PINs, while still maintaining the simplicity and scalability advantages of the original scheme. Finally, we investigate the usability of the two schemes with a sample of 34 current and potential customers of the banking system. Our findings suggest that the new scheme is more efficient, less susceptible to human error and better preferred by the target consumers.

/pdf/usably-secure-low-cost-authentication-for-mobile-banking-esqfijtll8.pdf

Saurabh Panjwani

Papers

Do not embarrass: re-examining user concerns for online tracking and advertising

Append-only signatures

Adaptive security of symbolic encryption

Usably secure, low-cost authentication for mobile banking

Append-Only Signatures.