This paper introduces fast algorithms for performing group operations on twisted Edwards curves, pushing the recent speed limits of Elliptic Curve Cryptography (ECC) forward in a wide range of applications. Notably, the new addition algorithm uses 1 8M for suitably selected curve constants. In comparison, the fastest point addition algorithms for (twisted) Edwards curves stated in the literature use 9M + 1S. It is also shown that the new addition algorithm can be implemented with four processors dropping the effective cost to 2M. This implies an effective speed increase by the full factor of 4 over the sequential case. Our results allow faster implementation of elliptic curve scalar multiplication. In addition, the new point addition algorithm can be used to provide a natural protection from side channel attacks based on simple power analysis (SPA).

Abstract. In this paper we present practical guidelines for designing secure block cipher key schedules. In particular we analyse the AES key schedule and discuss its security properties both from a theoretical viewpoint, and in relation to published attacks exploiting weaknesses in its key schedule. We then propose and analyse an efficient and more secure key schedule.

A brief verification study of river forecasts suggests the need to link river forecast process improvements more closely to forecast verification results. V erification must be an integral element of forecasting. Well-structured verification provides a means to improve forecast skill, to communicate with nonforecasters regarding resource needs, and to help forecast users optimize their decision making. Within the hydrology community however, few have focused any attention on verifying river forecasts. As a step toward encouraging hydrologists to verify their forecasts, this paper presents a verification study of National Oceanic and Atmospheric Administration/ National Weather Service (NWS) deterministic riverstage forecasts at 15 locations. The results of this study AMERICAN METEOROLOGICAL SOCIETY suggest that the hydrologic research and operations communities must join together to review, evaluate, and reconstruct the methods by which they update the hydrologic forecast process.The verification results described in this paper are for river-stage forecasts issued by NWS River Forecast Centers (RFCs). The NWS RFCs sit at the center of the U.S. flood warning capability. They provide guidance to the NWS Weather Forecast Offices (WFOs), which in turn issue flood watches and warnings. The NWS RFCs coordinate with other state and federal water management agencies when they issue their forecasts to ensure dam operations, irrigation demand and the like are integrated into the forecasts. There are 13 RFCs across the country, and each one is responsible for a different set of basins. A more detailed description of NWS river-forecasting operations can be found in Stallings and Wenzel (1995), Larson et al. (1995), andFread et al. (1995). In addition, the NWS RFCs describe their operations on their home pages, which can be found via the NWS home page (online at http://nws.noaa.gov).

Abstract. This paper is on efficient implementation techniques of Elliptic Curve Cryptography. In particular, we improve timings 1 for Jacobiquartic (3M+4S) and Hessian (7M+1S or 3M+6S) doubling operations. We provide a faster mixed-addition (7M+3S+1d) on modified Jacobiquartic coordinates. We introduce tripling formulae for Jacobi-quartic (4M+11S+2d), Jacobi-intersection (4M+10S+5d or 7M+7S+3d), Edwards (9M+4S) and Hessian (8M+6S+1d) forms. We show that Hessian tripling costs 6M+4C+1d for Hessian curves defined over a field of characteristic 3. We discuss an alternative way of choosing the base point in successive squaring based scalar multiplication algorithms. Using this technique, we improve the latest mixed-addition formulae for Jacobiintersection (10M+2S+1d), Hessian (5M+6S) and Edwards (9M+1S+ 1d+4a) forms. We discuss the significance of these optimizations for elliptic curve cryptography.

We investigate the physics of bidirectional injectionlocking in optoelectronic oscillators (OEO). In particular, we identify the effects of injection strength on phase noise and spurious modes for a dual injection-locked OEO.Our experimental data is then used to design a numerical model of a dual injection-locked OEO. This model will be used in the future to optimize the multi-dimensional injection-locking parameters to achieve minimal phase noise and spurious mode levels.