Street-level bureaucrats: En studie om möjligheten att skapa policy

In the book ”street-level bureaucracy dilemmas of the individual in public services” (2010) the author Michael Lipsky writes about the individual in public services. Lipsky presents a theory about street-level bureaucrats as policy makers. He argues that policy is created by the people at the bottom of the organizational hierarchy, the street-level bureaucrats. This is made possible by two interlinked factors, a relatively large distance from organizational authority witch leads to freedom in the daily routine. The purpose of this paper is to highlight the problem of seeing street-level bureaucrats as a homogeneous group. This essay questions Lipskys tendency to generalize various types of street-level bureaucrats’ possibility to make policy. Therefore the research question is: To what extent does organizational depth affect opportunity for street-level bureaucrats to make policy? By comparing two organizations with different organizational depth, the police and the healthcare, with the degree of freedom at these workplaces this study examine if these two factors correlate. Based on interviews this study finds that even though the organizational depth differs the opportunity to make policy does not vary

On LFSR based Stream Ciphers - analysis and design

Stream ciphers are cryptographic primitives used to ensure privacy in digital communication. In this thesis we focus on stream ciphers built using Linear Feedback Shift Registers (LFSRs). Several different stream ciphers are analysed and new attacks are presented. In addition, two new stream ciphers are presented, both based on the same design. The first attack is performed on SOBER-t16 and SOBER-t32. A new distinguishing attack is presented for simplified versions of the two ciphers, as well as for the complete version of SOBER-t16. Next, the cipher A5/1, used in the GSM standard for mobile telephones, is analysed. The resulting attack is an initial state recovery attack which recovers the secret key using approximately 5 minutes of known keystream. The attack takes roughly 5 minutes to perform on today's standard PC. Bluetooth is a well-known standard for wireless communication and the cipher responsible for the secrecy within that standard is called E0. An initial state recovery algorithm on E0 is presented, based on recently discovered correlations within the cipher. These new correlations are stronger than previously known. This attack, however, is only applicable to E0 in a theoretical perspective, since the required length of the observed keystream is longer than allowed in the Bluetooth standard. Following this, two distinguishing attacks are presented targeting clock controlled generators; the shrinking generator and the self-shrinking generator. The attack on the shrinking generator is based on a new observation that the majority bits of a block surrounding the tap positions in the LFSR output also fulfils the linear recurrence equation. The attack on the self-shrinking generator identifies two new classes of weak feedback polynomials. For the first class, both a distinguishing attack and an initial state recovery attack are presented. This distinguishing attack is remarkable in the sense that the required length of the observed keystream only grows linearly in the length of the shift register. For the second class of weak feedback polynomials a distinguishing attack is given. The final part of this thesis concerns the design of stream ciphers. Two new designs are presented, SNOW 1.0 and SNOW 2.0, the latter being an improvement on the former. These ciphers are designed to be very fast, especially in a software implementation

Piratverksamheten i Sverige och EU - Särskilt om varumärkesintrång

Denna uppsats behandlar ett antal åtgärder som har vidtagits inom gemenskapen för att försöka stävja den allt mer växande varumärkesförfalskningen och pirattillverkningen inom Sverige och EU. Denna olagliga verksamhet har funnits under en lång tid, och inledningsvis sågs det inte som ett större problem då det mest handlade om harmlösa t-tröjor och solglasögon utan någon skyddande verkan. Men denna syn har dock successivt ändrats med tiden. Numera kan det vara förfalskningar och kopior som är så pass välgjorda att det inte längre går att se någon direkt skillnad. Utbudet av de olagliga varorna är dessutom avsevärt mycket större i dagsläget än förr, som exempel kan nämnas drycker, möbler, läkemedel och frimärken. Inte ens de skyddsanordningar som skapats för att skilja original från kopia har fungerat, då även skyddet kopierats. Undersökningar har visat att problemet är otroligt stort och det nämns siffror uppemot 600 miljarder dollar som går förlorat varje år. Dessutom har denna handel ofta anknytning till den organiserade brottsligheten och terroristorganisationer. För att försöka bekämpa piratverksamhet inom den Europeiska gemenskapen lade kommissionen år 1998 fram en Grönbok med ett antal viktiga frågor rörande varumärkesintrång och pirattillverkning. Dessa frågor besvarades aktivt och presenterades av kommissionen ca 2 år senare i en ambitiös handlingsplan, som framförallt var inriktad på att få fram ett nytt direktiv där skyddet av de immateriella rättigheterna skulle säkerställas. Förslaget till direktivet kom den 30 januari 2003, men brister fanns och först den 29 april 2004 kom själva direktivet, som dock av vissa karaktäriserats som urvattnat då en rad kompromisser ligger bakom. Då det gäller den svenska tullmyndigheten så finns det ett antal lagar och förordningar att använda sig av då ingripande mot olagliga varor blir aktuellt. En av de senaste bestämmelserna på detta område är Rådets förordning (EG) nr 1383/2003 om tullmyndigheters ingripande mot varor som misstänks göra intrång i vissa immateriella rättigheter och om vilka åtgärder som skall vidtas mot varor som gör intrång i vissa immateriella rättigheter. Problem kan dock uppkomma då det gäller parallellhandel av varor, det finns nämligen inga nationella eller gemenskapsrättsliga instrument som tullen kan använda sig av för att ingripa mot just dessa varor, utan gällande bestämmelser är bara inriktade på varumärkesförfalskningar och pirattillverkningar. Detta kan te sig lite bekymmersamt då parallellhandel ofta är förknippat med förfalskade och piratkopierade produkter

VETE: Virtualizing the Trusted Execution Environment

This document is the final report for the SICS project Virtualizing the Trusted Execution Environment (VETE). This project was carried out in close collaboration with Ericsson Research and with support from ST-Ericsson. In this project, we desig an dimplement a hypervisor for the U8500 NovaThor platform that operates inside the Secure world of the main CPUs. The hypervisor will virtualize the underlying hardware in such way that the Trusted Execution Environment either directly or with the help of the hypervisor can provide secure isolation between the Trusted Applications, and between Trusted Applications and normal applications.VET

Distinguishing attacks on SOBER-t16 and t32

Two ways of mounting distinguishing attacks on two similar stream ciphers, SOBER-t16 and SOBER-t32, are proposed.. It results in distinguishing attacks faster than exhaustive key search on full SOBER-t16 and on SOBER-t32 without stuttering

SNOW - a new stream cipher

In this paper a new word-oriented stream cipher, called SNOW, is proposed. The design of the cipher is quite simple, consisting of a linear feedback shift register, feeding a finite state machine. The design goals of producing a stream cipher significantly faster than AES, with significantly lower implementation costs in hardware, and a security level similar to AES is currently met. Our fastest C implementation requires under 1 clock cycle per running key bit. The best attacks are generic attacks like an exhaustive key search attack

New Circuit Minimization Techniques for Smaller and Faster AES SBoxes

In this paper we consider various methods and techniques to find the smallest circuit realizing a given linear transformation on n input signals and m output signals, with a constraint of a maximum depth, maxD, of the circuit. Additional requirements may include that input signals can arrive to the circuit with different delays, and output signals may be requested to be ready at a different depth. We apply these methods and also improve previous results in order to find hardware circuits for forward, inverse, and combined AES SBoxes, and for each of them we provide the fastest and smallest combinatorial circuits. Additionally, we propose a novel technique with “floating multiplexers” to minimize the circuit for the combined SBox, where we have two different linear matrices (forward and inverse) combined with multiplexers. The resulting AES SBox solutions are the fastest and smallest to our knowledge

Another attack on A5/1

A5/1 is a stream cipher used in the Global System for Mobile Communications (GSM) standard. Several time-memory tradeoff attacks against A5/1 have been proposed, most notably the recent attack by Biryukov, Shamir, and Wagner, which can break A5/1 in seconds using huge precomputation time and memory. This correspondence presents a completely different attack on A5/1, based on ideas from correlation attacks. Whereas time-memory tradeoff attacks have a complexity which is exponential with the shift-register length, the complexity of the proposed attack is almost independent of the shift-register length. Our implementation of the suggested attack breaks A5/1 in a few minutes using 2-5 min of conversation plaintext

Another attack on A5/1

A5/1 is a stream cipher used in the GSM system. Several time-memory trade-off attacks against A5/1 have been proposed previously. This paper presents a completely different attack, based on ideas from correlation attacks

A new version of the stream cipher SNOW

In 2000, the stream cipher SNOW was proposed. A few attacks followed, indicating certain weaknesses in the design. In this paper we propose a new version of SNOW, called SNOW 2.0. The new version of the cipher does not only appear to be more secure, but its implementation is also a bit faster in software