Security Weaknesses in the APCO Project 25 Two-Way Radio System

APCO Project 25 (“P25”) is a suite of wireless communications protocols designed for public safety two-way (voice) radio systems. The protocols include security options in which voice and data traffic can be cryptographically protected from eavesdropping. This report analyzes the security of P25 systems against passive and active attacks. We find a number of protocol, implementation, and user interface weaknesses that can leak information to a passive eavesdropper and that facilitate active attacks. In particular, P25 systems are highly susceptible to active traffic analysis attacks, in which radio user locations are surreptitiously determined, and selective jamming attacks, in which an attacker can jam specific kinds of traffic (such as encrypted messages or key management traffic). The P25 protocols make such attacks not only feasible but highly efficient, requiring, for example, significantly less aggregate energy output from a jammer than from the legitimate transmitters

Evaluation of HRI payloads for rapid precision target localization to provide information to the tactical warfighter

High Resolution Imagery (HRI) with precise location and targeting data for the warfighter has become an integral part in today's asymmetric warfare environment. This thesis conducted practical testing of systems and employed qualitative research methods to evaluate HRI payloads for SUAS to provide rapid precision target localization to the warfighter. The research attempted to evaluate new HRI systems integration with the current SUAS's to produce accurate or reduced error images for intelligence and targeting data. The targeting solutions were to be evaluated against those calculated solutions achieved on a manned aircraft. This part of the evaluation was not completed due to the discovery of radio frequency noise interference induced by systems modifications required to fit the small confines of the SUAS platform. Targeting solution research was conducted using archival images from a manned flight mission. Once the system and technology is modified to eliminate the radio frequency noise there is a high probability of successfully proving the desired capability.http://archive.org/details/evaluationofhrip109455512Approved for public release; distribution is unlimited

Performance Study of Hybrid Spread Spectrum Techniques

This thesis focuses on the performance analysis of hybrid direct sequence/slow frequency hopping (DS/SFH) and hybrid direct sequence/fast frequency hopping (DS/FFH) systems under multi-user interference and Rayleigh fading. First, we analyze the performance of direct sequence spread spectrum (DSSS), slow frequency hopping (SFH) and fast frequency hopping (FFH) systems for varying processing gains under interference environment assuming equal bandwidth constraint with Binary Phase Shift Keying (BPSK) modulation and synchronous system. After thorough literature survey, we show that hybrid DS/FFH systems outperform both SFH and hybrid DS/SFH systems under Rayleigh fading and multi-user interference. Also, both hybrid DS/SFH and hybrid DS/FFH show performance improvement with increasing spreading factor and decreasing number of hopping frequencies