Current mechanisms for authenticating communication between devices that share no prior context are inconvenient for ordinary users, without the assistance of a trusted authority. We present and analyze seeing-is-believing, a system that utilizes 2D barcodes and camera-telephones to implement a visual channel for authentication and demonstrative identification of devices. We apply this visual channel to several problems in computer security, including authenticated key exchange between devices that share no prior context, establishment of a trusted path for configuration of a TCG-compliant computing platform, and secure device configuration in the context of a smart home.

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Seeing-is-believing: using camera phones for human-verifiable authentication

This is a high impact journal published by Annual Reviews, Inc., a nonprofit scientific publisher established in 1929 to promote the advancement of the sciences through critical reviews. Covering all areas of psychology research and practice, the Annual Review of Psychology is planned by a rotating committee of eight distinguished psychologists who invite qualified authors to contribute reviews of significant developments in the discipline.

Annual Review of Psychology

In this paper, we present Anagram, a content anomaly detector that models a mixture ofhigh-order n-grams (n > 1) designed to detect anomalous and “suspicious” network packet payloads. By using higher-order n-grams, Anagram can detect significant anomalous byte sequences and generate robust signatures of validated malicious packet content. The Anagram content models are implemented using highly efficient Bloom filters, reducing space requirements and enabling privacy-preserving cross-site correlation. The sensor models the distinct content flow of a network or host using a semi-supervised training regimen. Previously known exploits, extracted from the signatures of an IDS, are likewise modeled in a Bloom filter and are used during training as well as detection time. We demonstrate that Anagram can identify anomalous traffic with high accuracy and low false positive rates. Anagram's high-order n-gram analysis technique is also resilient against simple mimicry attacks that blend exploits with “normal” appearing byte padding, such as the blended polymorphic attack recently demonstrated in [1]. We discuss randomized n-gram models, which further raises the bar and makes it more difficult for attackers to build precise packet structures to evade Anagram even if they know the distribution of the local site content flow. Finally, Anagram's speed and high detection rate makes it valuable not only as a standalone sensor, but also as a network anomaly flow classifier in an instrumented fault-tolerant host-based environment; this enables significant cost amortization and the possibility of a “symbiotic” feedback loop that can improve accuracy and reduce false positive rates over time.

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Anagram: a content anomaly detector resistant to mimicry attack

Systems, methods, and media for outputting a dataset based upon anomaly detection are provided. In some embodiments, methods for outputting a dataset based upon anomaly detection: receive a training dataset having a plurality of n-grams, which plurality includes a first plurality of distinct training n-grams each being a first size; compute a first plurality of appearance frequencies, each for a corresponding one of the first plurality of distinct training n-grams; receive an input dataset including first input n-grams each being the first size; define a first window in the input dataset; identify as being first matching n-grams, the first input n-grams in the first window that correspond to the first plurality of distinct training n-grams; compute a first anomaly detection score for the input dataset using the first matching n-grams and the first plurality of appearance frequencies; and output the input dataset based on the first anomaly detection score.

Systems, Methods, and Media for Outputting a Dataset Based Upon Anomaly Detection

An example method includes detecting, using sensors, packets throughout a datacenter. The sensors can then send packet logs to various collectors which can then identify and summarize data flows in the datacenter. The collectors can then send flow logs to an analytics module which can identify the status of the datacenter and detect an attack.

System for monitoring and managing datacenters

Systems, methods, and media for enforcing a security policy in a network are provided, including, for example, receiving a plurality of events describing component behavior detected by a plurality of sensors, each sensor monitoring a different component of a plurality of components; attributing a first event of the plurality of events to a first principal; attributing a second event of the plurality of events to a second principal; determining whether the first and second events are correlated; storing a data structure that attributes each of the first and second events to the first principal, if it is determined that the first and second events are correlated; comparing the second event to the security policy; and modifying network behavior to enforce the security policy against the first principal based on the comparison of the second event to the security policy and the attribution of the second event to the first principal.

Systems, methods, and media for enforcing a security policy in a network including a plurality of components

The use of computers in public places is increasingly common in everyday life. In using one of these computers, a user is trusting it to correctly carry out her orders. For many transactions, particularly banking operations, blind trust in a public terminal will not satisfy most users. In this paper the aim is therefore to provide the user with authenticated communication between herself and a remote trusted computer, via the untrusted computer.After defining the authentication problem that is to be solved, this paper reduces it to a simpler problem. Solutions to the simpler problem are explored in which the user carries a trusted device with her. Finally, a description is given of two camera-based devices that are being developed.

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The Untrusted Computer Problem and Camera-Based Authentication

We describe a resource discovery and communication system designed for security and privacy. All objects in the system, e.g., appliances, wearable gadgets, software agents, and users have associated trusted software proxies that either run on the appliance hardware or on a trusted computer. We describe how security and privacy are enforced using two separate protocols: a protocol for secure device-to-proxy communication, and a protocol for secure proxy-to-proxy communication. Using two separate protocols allows us to run a computationally-inexpensive protocol on impoverished devices, and a sophisticated protocol for resource authentication and communication on more powerful devices.We detail the device-to-proxy protocol for lightweight wireless devices and the proxy-to-proxy protocol which is based on SPKI/SDSI (Simple Public Key Infrastructure / Simple Distributed Security Infrastructure). A prototype system has been constructed, which allows for secure, yet efficient, access to networked, mobile devices. We present a quantitative evaluation of this system using various metrics.

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Proxy-based security protocols in networked mobile devices

Cryptographic transformations are a fundamental building block in many security applications and protocols. To improve performance, several vendors market hardware accelerator cards. However, until now no operating system provided a mechanism that allowed both uniform and efficient use of this new type of resource.We present the OpenBSD Cryptographic Framework (OCF), a service virtualization layer implemented inside the operating system kernel, that provides uniform access to accelerator functionality by hiding card-specific details behind a carefully designed API. We evaluate the impact of the OCF in a variety of benchmarks, measuring overall system performance, application throughput and latency, and aggregate throughput when multiple applications make use of it.We conclude that the OCF is extremely efficient in utilizing cryptographic accelerator functionality, attaining 95p of the theoretical peak device performance and over 800 Mbps aggregate throughput using 3DES. We believe that this validates our decision to opt for ease of use by applications and kernel components through a uniform API and for seamless support for new accelerators. Furthermore, our evaluation points to several bottlenecks in system and operating system design: data copying between user and kernel modes, PCI bus signaling inefficiency, protocols that use small data units, and single-threaded applications. We identify some of these limitations through a set of measurements focusing on application-layer cryptographic protocols such as SSL. We offer several suggestions for improvements and directions for future work. We provide experimental evidence of the effectiveness of a new approach which we call operating system shortcutting. Shortcutting can improve the performance of application-layer cryptographic protocols by 27p with very small changes to the kernel.

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Cryptography as an operating system service: A case study

We introduce mix rings, a novel peer-to-peer mixnet architecture for anonymity that yields low-latency networking compared to existing mixnet architectures A mix ring is a cycle of continuous-time mixes that uses carefully coordinated cover traffic and a simple fan-out mechanism to protect the initiator from timing analysis attacks Key features of the mix ring architecture include decoupling path creation from data transfer, and a mechanism to vary the cover traffic rate over time to prevent bandwidth overuse We analyze the architecture with respect to other peer-to-peer anonymity systems – onion routing and batching mixnets – and we use simulation to demonstrate performance advantages of nearly 40% over batching mixnets while protecting against a wider variety of adversaries than onion routing

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Matthew Burnside

Papers

Systems, methods, and media for enforcing a security policy in a network including a plurality of components

The Untrusted Computer Problem and Camera-Based Authentication

Proxy-based security protocols in networked mobile devices

Cryptography as an operating system service: A case study

Low latency anonymity with mix rings