SRI International

About: SRI International is a nonprofit organization based out in Menlo Park, California, United States. It is known for research contribution in the topics: Ionosphere & Laser. The organization has 7222 authors who have published 13102 publications receiving 660724 citations. The organization is also known as: Stanford Research Institute & SRI.

The CHERI capability model: revisiting RISC in an age of risk

Abstract: Motivated by contemporary security challenges, we reevaluate and refine capability-based addressing for the RISC era. We present CHERI, a hybrid capability model that extends the 64-bit MIPS ISA with byte-granularity memory protection. We demonstrate that CHERI enables language memory model enforcement and fault isolation in hardware rather than software, and that the CHERI mechanisms are easily adopted by existing programs for efficient in-program memory safety. In contrast to past capability models, CHERI complements, rather than replaces, the ubiquitous page-based protection mechanism, providing a migration path towards deconflating data-structure protection and OS memory management. Furthermore, CHERI adheres to a strict RISC philosophy: it maintains a load-store architecture and requires only singlecycle instructions, and supplies protection primitives to the compiler, language runtime, and operating system. We demonstrate a mature FPGA implementation that runs the FreeBSD operating system with a full range of software and an open-source application suite compiled with an extended LLVM to use CHERI memory protection. A limit study compares published memory safety mechanisms in terms of instruction count and memory overheads. The study illustrates that CHERI is performance-competitive even while providing assurance and greater flexibility with simpler hardware

Sequential aggregate signatures and multisignatures without random oracles

Abstract: We present the first aggregate signature, the first multisignature, and the first verifiably encrypted signature provably secure without random oracles. Our constructions derive from a novel application of a recent signature scheme due to Waters. Signatures in our aggregate signature scheme are sequentially constructed, but knowledge of the order in which messages were signed is not necessary for verification. The aggregate signatures obtained are shorter than Lysyanskaya et al. sequential aggregates and can be verified more efficiently than Boneh et al. aggregates. We also consider applications to secure routing and proxy signatures.

Visual Contrast Sensitivity

Abstract: Like the modulation transfer function of man-made imaging devices, the contrast sensitivity of the human eye can be measured with sinusoidal grating targets of various spatial frequencies. Criterion-free psychophysical methods permit us to regard the contrast sensitivity as a direct measure of the subject's visual performance, independent of subjective factors. Under these conditions, not only the shape of the contrast-sensitivity function but also its absolute values show good agreement among normal subjects. However, the most interesting properties of this function cannot be attributed to the optics of the eye, but must be understood in terms of the image-processing activities of the visual pathways. The contrast-sensitivity function varies with the size, brightness, motion and flicker of the test target, with the adaptive state of the subject's retina, and with his eye-movements. Most of these effects can be explained in terms of known neurophysiology.