Certifying Machine Code Safe from Hardware Aliasing: RISC is not necessarily risky

Sometimes machine code turns out to be a better target for verification than source code. RISC machine code is especially advantaged with respect to source code in this regard because it has only two instructions that access memory. That architecture forms the basis here for an inference system that can prove machine code safe against `hardware aliasing', an effect that occurs in embedded systems. There are programming memes that ensure code is safe from hardware aliasing, but we want to certify that a given machine code is provably safe

Empirical Patterns in Google Scholar Citation Counts

Scholarly impact may be metricized using an author's total number of citations as a stand-in for real worth, but this measure varies in applicability between disciplines. The detail of the number of citations per publication is nowadays mapped in much more detail on the Web, exposing certain empirical patterns. This paper explores those patterns, using the citation data from Google Scholar for a number of authors

On the Security of Fully Homomorphic Encryption and Encrypted Computing: Is Division safe?

Since fully homomorphic encryption and homomorphically encrypted computing preserve algebraic identities such as 2*2=2+2, a natural question is whether this extremely utilitarian feature also sets up cryptographic attacks that use the encrypted arithmetic operators to generate or identify the encryptions of known constants. In particular, software or hardware might use encrypted addition and multiplication to do encrypted division and deliver the encryption of x/x=1. That can then be used to generate 1+1=2, etc, until a complete codebook is obtained. This paper shows that there is no formula or computation using 32-bit multiplication x*y and three-input addition x+y+z that yields a known constant from unknown inputs. We characterise what operations are similarly `safe' alone or in company, and show that 32-bit division is not safe in this sense, but there are trivial modifications that make it so

An Open Question on the Uniqueness of (Encrypted) Arithmetic

We ask whether two or more images of arithmetic may inhabit the same space via different encodings. The answers have significance for a class of processor design that does all its computation in an encrypted form, without ever performing any decryption or encryption itself. Against the possibility of algebraic attacks against the arithmetic in a `crypto-processor' (KPU) we propose a defence called `ABC encryption' and show how this kind of encryption makes it impossible for observations of the arithmetic to be used by an attacker to discover the actual values. We also show how to construct such encrypted arithmetics

Multi-heme Cytochromes in Shewanella oneidensis MR-1:Structures, functions and opportunities

Multi-heme cytochromes are employed by a range of microorganisms to transport electrons over distances of up to tens of nanometers. Perhaps the most spectacular utilization of these proteins is in the reduction of extracellular solid substrates, including electrodes and insoluble mineral oxides of Fe(III) and Mn(III/IV), by species of Shewanella and Geobacter. However, multi-heme cytochromes are found in numerous and phylogenetically diverse prokaryotes where they participate in electron transfer and redox catalysis that contributes to biogeochemical cycling of N, S and Fe on the global scale. These properties of multi-heme cytochromes have attracted much interest and contributed to advances in bioenergy applications and bioremediation of contaminated soils. Looking forward there are opportunities to engage multi-heme cytochromes for biological photovoltaic cells, microbial electrosynthesis and developing bespoke molecular devices. As a consequence it is timely to review our present understanding of these proteins and we do this here with a focus on the multitude of functionally diverse multi-heme cytochromes in Shewanella oneidensis MR-1. We draw on findings from experimental and computational approaches which ideally complement each other in the study of these systems: computational methods can interpret experimentally determined properties in terms of molecular structure to cast light on the relation between structure and function. We show how this synergy has contributed to our understanding of multi-heme cytochromes and can be expected to continue to do so for greater insight into natural processes and their informed exploitation in biotechnologies

The Secret Processor Will Go to the Ball: Benchmark Insider-Proof Encrypted Computing.

‘Encrypted computing’ is an approach to preventing insider attacks by the privileged operator against the unprivileged user on a computing system. It requires a processor that works natively on encrypted data in user mode, and the security barrier that protects the user is hardware-based encryption, not access. We report on progress and practical experience with our superscalar RISC class prototype processor for encrypted computing and supporting software infrastructure. This paper aims to alert the secure hardware community that encrypted computing is possibly practical, as well as theoretically plausible. It has been shown formally impossible for operator mode to read (or write to order) the plaintext form of data originating from or being operated on in the user mode of this class of processor, given that the encryption is independently secure. Now we report standard Dhrystone benchmarks for the prototype, showing performance with AES-128 like a 433 MHz classic Pentium (1 GHz base clock), thousands of times faster than other approache

On obfuscating compilation for encrypted computing

Copyright © 2017 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved. This paper sets out conditions for privacy and security of data against the privileged operator on processors that 'work encrypted'. A compliant machine code architecture plus an 'obfuscating' compiler turns out to be both necessary and sufficient to achieve that, the combination mathematically assuring the privacy of user data in arbitrary computations in an encrypted computing context

A practical encrypted microprocessor

Copyright © 2016 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved.This paper explores a new approach to encrypted microprocessing, potentiating new trade-offs in security versus performance engineering. The coprocessor prototype described runs standard machine code (32-bit OpenRISC v1.1) with encrypted data in registers, on buses, and in memory. The architecture is 'superscalar', executing multiple instructions simultaneously, and is sophisticated enough that it achieves speeds approaching that of contemporary off-the-shelf processor cores. The aim of the design is to protect user data against the operator or owner of the processor, and so- called 'Iago' attacks in general, for those paradigms that require trust in data-heavy computations in remote locations and/or overseen by untrusted operators. A single idea underlies the architecture, its performance and security properties: it is that a modified arithmetic is enough to cause all program execution to be encrypted. The privileged operator, running unencrypted with the standard arithmetic, can see and try their luck at modifying encrypted data, but has no special access to the information in it, as proven here. We test the issues, reporting performance in particular for 64-bit Rijndael and 72-bit Paillier encryptions, the latter running keylessly

A pragmatic cluster randomised trial evaluating three implementation interventions

Background Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting. Methods A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients' experiences, and stakeholders' experiences of implementation, including influences. ANOVA was used to test differences over time and interventions. Results Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility. Conclusions This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions' impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance. Trial registration ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE