Authenticating streamed data in the presence of random packet loss

We propose a new scheme for authenticating streamed data delivered in real-time over an insecure network. The difficulty of signing live streams is twofold. First, authentication must be efficient so the stream can be processed without delay. Secondly, authentication must be possible even if some packets in the sequence are missing. Streams of audio or video provide a good example. They must be processed in real-time and are commonly exchanged over UDP, with no guarantee that every packet will be delivered. Existing solutions to the problem of signing streams have been designed to resist worst-case packet loss. In practice however, network loss is not malicious but occurs in patterns of consecutive packets known as bursts. Based on this realistic model of network loss, we propose an authentication scheme for streams which achieves better performance as well as much lower communication overhead than existing solutions. We have implemented our constructions as plug-ins to the RealSystem platform from Real Networks to authenticate audio and video streams

The Design and Implementation of Datagram TLS

A number of applications have emerged over recent years that use datagram transport. These applications include real time video conferencing, Internet telephony, and online games such as Quake and StarCraft. These applications are all delay sensitive and use unreliable datagram transport. Applications that are based on reliable transport can be secured using TLS, but no compelling alternative exists for securing datagram based applications. In this paper we present DTLS, a datagram capable version of TLS. DTLS is extremely similar to TLS and therefore allows reuse of pre-existing protocol infrastructure. Our experimental results show that DTLS adds minimal overhead to a previously non-DTLS capable application

Design of a compact direct digital frequency synthesizer with 12 bit amplitude and 32 bit frequency resolution

This paper describes the design of a monolithic direct digital frequency synthesizer. The circuit realizes a 12 bit output sine wave with a frequency resolution of 32 bit. The core of the 1.2 μm CMOS implementation consists of approximately 6,000 transistors and occupies an area not larger than 1.5 mm2. The circuit is aimed at a maximum tuning range of 100 MHz, or equivalently, a clock rate of 200 MHz. This upper value yields a minimum frequency increment of 0.023 Hz. The system exhibits a total latency of 14 clock periods

The genetic improvement of farmed tilapias project: Impact and lessons learned

In response to challenges that the developing world confront on food security and malnutrition, the last two decades have witnessed increased efforts in genetic improvement to enhance production traits of commercially important aquatic species. From the 1980s to the present, several institutions in developing countries have been engaged in such R&D activity and it is recognized that the collaborative program on Genetic Improvement of Farmed Tilapias (GIFT) has spurred the development of several tilapia and carp breeding programs that now exist in numerous developing countries. The GIFT is a collaborative R&D program conducted by the WorldFish Center (formerly, International Center for Living Aquatic Resources Management, ICLARM) and its partners from the Philippines and Norway aimed to develop methodologies for the genetic improvement of tropical finfish of aqua-culture importance. The GIFT project has demonstrated that selective breeding is a feasible, cost effective, and sustainable approach to the genetic improvement of tropical finfish, and also confirmed the importance of a multidisciplinary approach that enabled the assessment of economic viability, social acceptability, and environmental compatibility, thus, creating confidence among planners and administrators, all of which facilitated the transfer of research findings to farming systems in a host of countries. The program and its successors, such as the International Network on Genetics in Aquaculture (INGA), demonstrated that networking and partnership building among national institutions in developing countries, advanced scientific institutions, and regional and international organizations can play a major role in accelerating research and the success of R&D

SiRiUS: Securing Remote Untrusted Storage Eu-Jin

This paper presents SiRiUS, a secure file system designed to be layered over insecure network and P2P file systems such as NFS, CIFS, OceanStore, and Yahoo! Briefcase. SiRiUS assumes the network storage is untrusted and provides its own read-write cryptographic access control for file level sharing. Key management and revocation is simple with minimal out-of-band communication. File system freshness guarantees are supported by SiRiUS using hash tree constructions. SiRiUS contains a novel method of performing file random access in a cryptographic file system without the use of a block server. Extensions to SiRiUS include large scale group sharing using the NNL key revocation construction. Our implementation of SiRiUS performs well relative to the underlying file system despite using cryptographic operations. 1