Of these transfers, however, many are visually obvious to the user.

many websites use mouse-over events to change the appearance of the item being moused-over.


interactive protocols to unpack encrypted signals for applying SSP tools.

the element-wise scheme satis.es the non-interactive property.


In a distributed system the underlying relationship among the parties is peer-to-peer rather than hierarchical.

while it is reasonable to think that there exists a unique policy administrator which decides upon integrating multiple rules, this is not always the case when dealing with policies speci.ed by autonomous subjects.


The simplest type of policy for which this point can be made is the separability policy [20, 15] which says that no domain may interfere with any other.

for set of domains U, separability is the policy .U = { (u, u) | u .


The proof strategy is that C randomly selects an uncorrupted user J from the set of uncorrupted users and lets J be the targeted user in the Challenge phase.

if j * = J in the Challenge phase, the challenger will proceed the anonymous game; otherwise abort.


However, since A does not contribute in spreading in the Bitcoin network any transaction herself, her location does not affect the outcome of the attack.

the sole role of Ais to send TRV to V using a direct connection in the Bitcoin network and TRA to the helper nodes using a direct TCP connection.


In this paper we extend those ideas about software updatebyoutlining anarchitecturefora simpleproperty-based sealing andbypresenting aproof of concept implementation based on OpenTC design principles, namely the combined use of Trusted Computing and virtualization.

the use of properties was .rst proposed to mitigate the problems related with remoteattestation(referto[9,10] for 2 memory isolation and communications subject to .ow control policies.


Software attestation is a protocol between a veri.er V and a (potentially malicious) prover P where the latter belongs to a class of devices with clearly speci.ed characteristics.

whenever we speak about a prover P, we refer to a device that belongs to this class.


When generating an n-gram model for malware detection, we follow a standard approach.

we .rst extract n-gram models for a set of malware programs and a set of benign programs (called the training data).


This means that for malicious peers to double-spend a BTC without being detected, they would not only have to redo all the work required to compute the block where that BTC was spent, but also recompute all the subsequent blocks in the chain.

this 3the block contains correctly formed transactions that have not been previously spent, and has a correct PoW.


Summary of Results: By running ClickMiner on the network trace recorded during the user-generated browsing session described above, we were able to reconstruct the full chain of user-browser interactions that led the user to the malware download.

clickMiner reduced the amount of information to be analyzed by 3MD5: c94f917fdc39dfb7245ebdd674b2bdf8  a forensic analyst from 316 HTTP exchanges to only 6 click graph nodes, as shown in Figure 6.


It saves the state of the current domain onto the stack and loads the parameters into the registers.

it stores the target function address into one of the registers (r12 in our prototype).


obtained after updating ., we may want to impose this constraint: ..R = ..R. (1) The effects of an update should be con.ned to a certain set U of users.

updates are supposed to be transparent to users outside U in the sense that their permission sets in .


the [guard s] participation is left implicit [2, p. 13].

the guard s beliefs are imported into p s beliefs at each world.


heraclitus asserted that contradictions existed and indeed were central to identity: Not only could it be stated that identity is the strife of oppositions but that there could be no identity without such strife within the identity.


Both the entered keys and their purpose (i.e., place on the screen), displayed on the same screen, can be stolen simultaneously by a single display capture.

software key-boards often enhance the entered key by luminance changing or visually popping-up to support user confirmation, which makes it easier to steal key information.


The list of sensitive .les needs to be speci.ed, but we can assume that any .le that the consumer does not consider to be public is classi.ed as sensitive.

this means that the web log .le is considered sensitive.


This is where we use the assumption about the same set of polyhedra that are corrupted over time.

if we relax this assumption, then pairwise intersect does not guarantee that the true value is contained in the fusion polyhedron.


Our research on graphical passwords has shown that assigned graphical passwords are indeed more memorable than assigned text passwords [25], and that the image cues associated with some graphical passwords can help users distinguish multiple passwords from each other [5].

we developed Image PassTiles, a cued-recall graphical password system where the user is shown an image overlain by a grid.


PRACTICAL USE AND COMPLEXITY ANALYSIS 6.1 Amortized query costs Our proposed schemes can amortize query costs.

our designs are able to use the same commitment/decommitment queries and PCP queries across many instances of the same circuit (with di.erent input/output).


2.3 Implementation Our prototype uses the Activiti BPMN Platform (http: //www.activiti.org/).

we extended the Activiti Eclipse Designer and the Activiti Process Engine.


A fundamental question to be addressed is who should decide what the public policy properties of the computer world should be, and what will empower them to implement their decisions?

what are and what should be the roles of and interplay between government, non-profit public interest groups, voluntary industrial standards, market forces driven by end consumers, and the technology itself?


One weakness of our approachisthat wedo not address alltypes of malicious programs that could infect users machines.

malware programs such as keystroke loggers are not signi.cantly harmedbySpySaver, aslongastheinformation suchprograms collect canbe validatedindependently.


We refer to this as the role mapping problem.

given a requested set PRQ, the system finds an appropriate role set (referred as RRQ) through which the user can acquire PRQ.


However, SELinux only targets the kernel-level, and misses high-level semantics of Android s middleware.

we are not aware of any security extension providing e.cient and scalable application and data isolation on di.erent layers of the Android software stack, which is essential for deploying Android in the business world.


The result of our invariant generation and assertion checking process is a control .ow graph where each program control point is annotated with a set of predicates that are true at that location.

an abstract state graph that captures both the control and the data .ow properties of a program.


We have then studied properties of the combined policies, such as totality and consistency.

we have given suf.cient conditions for consistency using modularity results that are available for rewriting systems.


On the other hand, the contextual system attribute allows the speci.cation of a general set of system related attributes that can be associated with a subject or an object.


Graphs chosen from Mm,n,d will be, with high probability, very good expanders.

we expect that small sets S of top vertices will have almost d|S| neighbors.


It also has an additional rule for expressions, for typing signature veri.cations; this rule is identical to rule OP except for its cryptographic data types: OPVER f y : t(e) f m : Sig t(es)(e) f kv : Kv F K(e) F(t)= t(es) fV(t + y, m, kv): Data (e) Rule PROBFUN is the generic rule for typing probabilistic functions; it requires that all variables have Data types and prevents explicit .ows from the parameters Ay to the results Ax.

pROBFUN applies to the functions S, E, and D in case we do not rely on cryptographic assumptions.


e s = Thedistributionispeakedaround v beingzero, andfalls offquickly as v gets bigger.


HOMOMORPHIC MACS WITH EFFICIENT VERIFICATION In this section, we describe our construction of homomorphic MACs with e.cient veri.cation for multi-labeled programs as introduced in Section 3.3.

the following theorem summarizes the main result of this work which is obtained by combining the EVH-MAC construction (see below) and our concrete instantiation of the PRF with amortized closed-form e.ciency based on the Decision Linear assumption (Section 4.3).


Consequently, a list is maintained for each node, rating from 0 to 5 the number of times the corresponding node has acted illegally.

the value of 0 indicates a node that operates normally and has never been detected for malicious activities, whereas, the value of 5 denotes that the node has already been detected 5 times for attacking actions.


Since the PI N O C C H I O evaluation key size is proportional to the size of the circuit and the certifying algorithm has a more ef.cient circuit implementation than the one of BFS in Figure 3, the server storage for the certifying algorithm is much smaller.

the server storage is reduced by 32340× on a graph with 1,000 nodes and the gap grows on larger graphs.


UAQ: A Framework for User Authorization Query Processing in RBAC extended with Hybrid Hierarchy and Constraints Yue Zhang University of Pittsburgh 135 N. North Bellefield Ave. Pittsburgh PA 15260 1-412-624-4099  yuz20@pitt.edu ABSTRACT A key issue in RBAC systems is how to efficiently handle the user authorization process.

whether or not to grant a user s request to acquire a set of requested permissions or to activate a set of requested roles in a single session.


Proof: It is well known and easy to see that conjunctive queries with inequalities are preserved under one-to-one homomorphisms.

if his a one-to-one homomorphism from Jto Jm2, and if is a R-ary conjunctive query with inequalities and y(a(yod dodoa)n n(Jy), then (hn((ayo)od d doh))n(m2Jy)o.


Our results, plotted in Figure 2, indicate that coresidence of multiple zones on the same name server (IP address) is a common practice.

60% of the name servers of Alexa domains and 70% of the name servers of TLDs, host more than 2 zone .les.


This scheme is ef.cient and is well suited for, for instance, pay-per-view service, but does not work in our setting because there is no way in this scheme to stop the chain and force subscription termination.

in order for a single subscription to be terminated, the system-wide key must be changed.


All deception requires deceit as said by Bennett and Waltz [3].

all deception requires the deceiver to intentionally lie about something to the target.


First, we additionally encode the length of string literals as decimal logarithm.

sTR.01 refers to a string with up to 101 characters, STR.02 to a string with up to 102 characters and so on.


Grant-safety requires that, if a permission is granted to a subject during the chain of commands, it be required by the action.

no permissions are granted and later revoked.


Therefore, it will not trigger alarm for the case shown in Figure 1.e.

without correlating multiple jump instructions, anomalous execution paths cannot be discovered when each jump instruction jumps to a target that is considered normal.


Given the potentially large number of mobile devices, scalability becomes a critical issue.

wireless sensor networks (WSNs) [1] comprise of a higher number of nodes scattered over some region.


Flexibility: The protocols should be flexible.

they should allow, all in one protocol superset:  Multiple wallet holders per user, e.g., a bank for financial information and a doctor for medical information.


)= s, where y .Y  Pr(s)= Pr(s|z), where z .Z We will focus on solving the secure coding problem at the level of bits.

our goal is to .nd f and f, such that for any m-bit source message s, j  encodes s via f into an n-bit message x, k decodes s via f and the knowledge of ., while e guesses s correctly with a probability that not better than 1 2m even if it knows f and f (regarded as perfect secrecy).


Domain-speci.c constraints encode rules that are formulated by a domain-expert.

whether the resource manipulation embodied by a .ngerprint is security 1The variable old de, which ext2 delete entry is invoked with on line 11 is derived from old dir and old dentry.


However, the server-side analyzer can simply block any game client that refuses to send the user-input stream.

a simplepolicyof nouser-input,nogame cansimply thwartthis potential evasion.


where F[Verify, M, PK]Ati~ represents Alice's output, F[Verify, M, PK]Bob represents Bob's output, and .£ is a special symbol.

our goal is that Alice learns nothing and Bob learns F[Verif~c,M, PK]sob(P,a) without learning anything else.


The main feature missing from OMA REL is delegation, which is not used in any real digital rights management systems of which we are aware.

oMA REL serves to illustrate all of the limitations of the formalisations that we described in Section 2, and our solution to them.


The main difference between these SAPs lies in the key distribution schemes.

when the material of temporary handoff key is updated, which is similar to the procedure depicted in Figure 3 (a), SAP v1 lets APs distribute temporary handoff keys to MTs using unicast.


The app developer can also leverage other indirect mechanisms to define her policies whenever she is building the app s functionality over a mobile channel.

morbs allows the developer to set her policies regarding a scheme/intent her app claims within the app s manifest file (for Android) or .plist (for iOS), under a new property allowedOrigins.


For example, in DLMS/COSEM, the DKs are defined as ones that are used for the encryption of unicast xDLMS APDU.

the DKs are unique session secret keys between two communication devices, which protect xDLMS APDU transmitted between a COSEM client, Central DCS or Concentrator, and a COSEM server.


Ideally, most user-groups can be by the DBPsolver in this study.

our approach identi.ed as sets of users with the same job code.


As the proof of Theorem 1 does not use the marking condition, innocent users are not likely to be accused even if the pirates can .nd the positions of the .ngerprint code and thus they can break the marking condition.

we can be reasonably sure that any accused user is a member of the group of pirates even if we do not know any bound on the size or power of this group.


However, for small values of |A| (especially, |A| < 28k+6.65) then one may get a counter-intuitive result.


However, many interesting open problems still exist in the management and analysis of obligations.

we would like to investigate the following problems in the future.


In short, the idea of combating domain .ux by simply acquiring more domains is clearly not scalable in the long term, and new approaches are needed to tilt the balance away from the botmasters.

the security community shouldbuilda stronger relationship with registrars.


Furthermore, the expected subrange interval lies symmetrically around N+1 .For |D| = 2, this reduces 2 the IND-OCPA properties of the random subrange selection approach to that of the approach used in the subrange.

it is again possible to adopt the argument given in [12], to show that for this speci.c domain size random o.set addition provides a higher level of IND-OCPA than random subrange selection in combination with the ideal object or a random uniform sampling approach.


have proposed the notion of PEI(policy,enforcement,implementation)models[31].

they have introduced a distinction between policy goals, which are traditionally high-level and abstract, and enforcement mechanisms, which de.ne a usable structure for creating an implementation.


Table 1: Error rates per click and completion time per game type Game Type Completion Time (s) mean (std dev) Error Rate Per Click mean Ships 4.51 (1.00) 0.04 Animals 9.10 (0.96) 0.05 Parking 4.37 (0.90) 0.09 Shapes 5.26 (0.59) 0.03 Error Rates: An important result is that all the tested games yielded 100% accuracy (overall error rate of 0%).

none of the participant failed to complete any of the games within the time out.


Similarly, smcoutput is used to specify output variables and the output party who is to learn each of them.

including smcoutput(x,1) for private x will instruct the compiled program to output shares of x into a .le which at the end of the computation is sent to output party 1.


In particular, looking at the analysis of [1], the (truncated) PRG G ' inside the refresh procedure is only needed to ensure the state pseudorandomness of their construction.

if one drops (only the) state pseudorandomness from the BH model, the simpli.ed BH construction is already robust in their model.


In addition to identifying documented kernel objects, we also aim to extract partial knowledge of undocumented kernel objects.

we would like to discover types of the pointer .elds, including both data pointers and function pointers.


In this class, the querier is only allowed to retrieve one record at each session.

the privacy of the database is breached if the querier learns more than single record at a time [28].


It is a program that collects outputs from all available sensors and combine them together using defined rules.

a concentrator has two tasks, combining sensor outputs and processing them.


The .rst term of that formula is constant and cannot be changed, therefore the problem of computing an optimal solution reduces to maximizing the second term of the equation.

in the optimal partitioning of n documents into m groups the sum of minimal elements of the groups is maximal.


Note that the windows are non-overlapping and that a window corresponds to a single extracted data point in our pro.ling data.

each observation in a user s behavioral pro.le is a summary over a window of N mouse movements.


CONCLUSION We show how mesoscopic properties of a social network can be leveraged to improve the degree of de-anonymization of anonymized social network datasets.

decomposing the network into communities allows for de-anonymization at a coarser granularity .rst, and then at the node level.


In this framework, a Policy Manager module is added into a normal DSMS to make it a Hippocratic DSMS.

this module manages the access control policies specif ed by the streaming data providers and/or the system administrator.


CIPHERTEXT TRANSLATION We now give a solution to the AEAD-problem that permits arbitrary associated-data.

we show how ¨ to transform an AE-scheme .


for all signature schemes S in the system, using a simple padding with random bits.

all signatures in the system would be L * bits long and look completely random, no matter how they were produced.


Several tools have been developed to assist policy authors for the veri.cation and analysis of policies, but most of them are limited in the types of analysis they can perform.

they are not able to reason about predicates of non-boolean variables and, even if they do, they do it ine.ciently.


In contrast to a naive representation with d dimensions, this feature space describes states independently of absolute di.erences.

each state change induced by the consumer is treated equally, whether it involves switching on a small desk lamp or a powerful washing machine.


Then pt matches pA s .phases[t * - j + 1].T .

messages m1 of those two transcripts are equal, and so are messages m2 of those two transcripts.


Again, note that the Amazon AWS keys are not password-protected.

an attacker that gains access to these keys is then able to instantiate Amazon resources (e.g.


Especially, we inject the Consent Management Service, Policy Composition Service, and EHR Authorization & Selection Service as the major system modules to convey the core features of our proposed approach.

the Consent Management Service enables the patient control by collecting and verifying the patient s access control policies as encapsulated in consents.


On the other hand, an enterprise would like to outsource business capabilities not only to reduce cost but also to take advantage of the best skills available outside the company.

many traditional businesses depend on outside suppliers due to the lack of internal skills for effective Internet marketing.


In particular, it can provide the following bene.ts: 1) it provides a designer with more realistic measure of SCA resistance at design time; 2) it enables integration of the right level of protection; and 3) as we observe later, the PDN causes variation in SCA resistance with operating frequency, which helps a designer to choose right frequency of operation and/or accomplish balanced protection across frequency spectrum.

the paper makes the following key contributions.


The StorageManager is an L4 process which encrypts data from other compartments and seals the data to the integrity measurements of the TCB, using the sealing function of the TPM via TrustManager.

the integrity measurements of the TCB include all trusted software components as depicted in Figure 3.


We give a feasibility evaluation of our full privacypreserving solution.

we describe our implementation of the authentication protocol and the bill computation protocol.


., k - 1, where each yi is chosen randomly from Zq and A = rk-1 A2i i , and showing i=0 that each xi hidden in com(xi) is either 0 or 1.

the exact statement that the user proves is of the form: PK{(a, ß, ., d, d0, .


What should be the user-study methodology for access control systems?

bene.ts of lab vs. .eld studies, and what each can teach us about the usability of access control systems?


When investigating this issue we found out that a single instance of Node runs in a single thread [2].

if CaWICC is working in server-side generation mode, then it relies on Node.js and, thus, only utilizes -without further implementation -only one CPU core.


Key-evolving signature scheme is a quadruple of algorithms KESig =(Gen,Upd,Sign,Vf), where: KESig.Gen, the probabilistic key generation algorithm.

input: a security parameter k. N (given in unary as 1k); and the total number of periods T; Output:a pair (SK 0,PK ), the initial secret key and the public key;  4randomness of the evolution was optional for forward-security, but is crucial for tamper-evidence; while one-wayness of the evolution was of central value for forward-security, but is optional for tamper-evidence.


Many current systems o.er a large attack surface, because they still deploy large amounts of native code implemented in unsafe languages such as C/C++.

modern smartphones have recently become an appealing attack target (e.g., [11, 8]).


Our iOS policy framework is closely related to these works.

we enable SFI for iOS applications, by instrumenting all calls to the Objective-C runtime.


Hence, to prove security we show that solving this variant of DUE assumption (denoted by DUE1) implies a solution to the original DUE problem.

given a random (m, n, d) graph with a planted shrinking set, an algorithm for DUE1 can be used to distinguish with some constant advantage between nodes that participate in the shrinking set to other nodes.


Also, if it is not expected, then it should not be satis.ed by the enforcement behavior (line 10).

there should be a one-toone correspondence between the expected and enforcement behaviors.


We implemented our scheme by modifying the popular Pretty Good Privacy (PGP) encryption software suite [3].

we modi.ed GnuPG 1.2.0 [21], a free software replacement for PGP.


The evaluation showed that PassShapes could be more easily and longer remembered when the repeated input strategy was applied.

the PassShape is practiced several times within one session by actively drawing it.


We restrict to the case in which a user is entitled to only one value for each attribute.

we do not consider the case, for example, in which a user is both male and female.


Our analysis reveals both positive and negative perceptions that security practitioners have for IDSs, as well as several issues encountered during the initial stages of IDS deployment.

practitioners found it di.cult to decide where to place the IDS and how to best con.gure it for use within a distributed environment with multiple stakeholders.


Our formalization of hybrid security uses ideal functionalities that are aware of both the set of corrupted parties and the computational power of the adversary.

the behavior of the functionality, and hence the security guarantees, varies depending on both parameters.


During the kernel build, the data sections are not copied or modi.ed: they remain unchanged when compared to a base kernel.

the data relocations in the split-base and split-hardened code must refer to the same data.


6.2 Analysis of the Security Architecture Our security architecture leverages the underlying security hardware to satisfy the requirements (SR1) and (SR2).

it relies on a separate processor providing an isolated execution environment and a dedicated secure memory.


In the ideal world, there is a trusted party T through whom all parties interact.

in the ideal world, values stored in tags are not visible to the adversary directly, and instead it must interact with T to obtain readings.


An important aspect of this cloud computing service is that the instance s maintenance is completely under the responsibility of the user.

she is 1428  Figure 1: System Architecture the one who can be held responsible for any content provided by the machine, and she is the one who has to assure its security.


This line of work does not address the dynamic and noninteractive nature of on-the-.y MPC.

once a subset of parties and a function are chosen, the protocols of [19, 4] require the parties to be online and run an interactive MPC protocol to generate a joint public key.


Another novel feature of our approach is that policies on access to personal data is facilitated in a distributed as well as a dynamic context.

we allow data subjects to choose freely what sources of information are to be used to determine authorized access to their data.


Before turning our attention to this computation of z, we observe that we can choose, without loss of security, the modulus of the additive-splitting to be the same as the one for the homomorphic encryption system.

if arithmetic is modulo T for the homomorphic encryption, then (1) we can assume that P1 (resp., P2 ) initially has xand (1) (2) (2) (1) (2) y(xand y), such that x+ xmod T = x, and (1) (2) y+ ymod T = y.


In another variant, TI is partitioned according to the origin AS.

we de.ne Ta,I as the elements of TI that share the same origin AS.


We now ask two questions: Guest perspective Given a quota of DMA mappings, what is the optimal eviction strategy?

how should the guest use its given quota of DMA mappings so that the total number of remappings (evictions) is minimized?


We developed a Fine-Grained Detector derived from BotMiner [7] and BotSni.er [5], and we plugged it into our botnet detection framework.

we used two components: i) an implementation of the malicious Figure 2: Packet Sampling Architecture activities detector derived from BotMiner s A-Plane monitor, which can identify groups of similar malicious activities based on the attack features (e.g., the scanned port, the exploits or binary content), and ii) BotSni.er s IRC-based botnet detection module.


During this session the user has a trust level which allows her to use the roles associated with that trust level.


4.2 Unknown degradation schedule We now consider the more general online service setting in which the degradation scheme is unknown.

the center does not know when or if a user will be degraded or revoked, or when or if the user will be reinstated as a privileged user.


If A later corrupts some players in pid, then due to the way corruptions are handled by S this will not introduce any noticeable di.erence from the point of view of Z (again relying on Claim 6, the assumed AKEsecurity of 1, and the pseudorandomness of F ).


Our goal here is to design systems that preserve the user s privacy as much as possible, while remaining auditable from the viewpoint of the service providers.

a user should have control over which claims are presented, but we do not attempt to make repeated uses of the user s credential unlinkable.


Now, nodes act like switches, which can block or unblock enforced .ows.

in periodic role enabling/disabling, each role is associated with a periodic expression that indicates the activation period of the role, e.g., all ·Y ear +{1, 4}·Months b 2 represents the set of intervals starting at the .rst and fourth month of every year, and having a duration of two months [6].


Per-channel puzzle solution: Another desirable property is for the work done by a client to apply on a per-channel basis, rather than a per-puzzle basis.

we would like a client that has solved a puzzle for a particular channel to be able to e.ciently compute the token for the same channel number on any server.


The job of split is to produce two strings: one to be passed to unrank for formatting, and one that will be passed along as-is.

split takes up to t + m bits (and at least t bits) from the front of the bu.er, which we refer to as C'.


EXPERIMENTAL RESULTS In this section, we report on our preliminary experiments towards building a generic toolkit for evaluating both sanitization methods and inference attacks on geolocated data.

we describe some clustering algorithms and heuristics, which can be used as inference attack, and evaluate their e.ciency for the identi.cation of POIs, even after the application of sanitization mechanisms such as sampling and perturbation.


This 2Note that these assumptions are for presentation purposes only, and our data structures can easily be generalized to other grids that are not of this form.

it is not necessary to increase the actual size of the grid to obtain m and n of the above form, but instead rounding can be used in computing partitions of the grid.


Further, this communication channel is restricted to be a stream of bits whose semantics is well-understood.

each 0 bit in the stream denotes a violation of regulatory compliance, while a 1 bit denotes otherwise.1 The client can setupa user daemon(e.g., within Udom0) that is awakenedby the SSChypervisor uponevery new bit transmitted bytheMTSDoverthis channel.An honest clientthatdoesnotviolate the provider s regulatory compliance policies should therefore only expect to see a stream of 1s transmitted to Sdom0.


= t · 2do = O(t)· o. td d·tg  4.3 Oblivious Bloom Intersection The idea of the basic protocol is shown in Figure 2.

to run Algorithm 3 by two parties using oblivious transfer.


We measured the Sechduler s overall performace overhead on our testbed system s overall throughput.

we employed the ab Apache Webserver benchmarking toolset to measure the system throughout.


6R is the average degree of the vertices in VR  6X is the average degree of the vertices in VX  6R is the average number of passwords associated with a response.


4.1 Evaluation Criteria The performance of random key pre-distribution schemes can be evaluated on the basis of several criteria [2, 3, 4, 5, 6, 7].

we choose connectivity and resilience against node capture as the criteria for performance evaluation.


We assume an attacker is already in possession of the mobile device, and the password (can be PIN or gesture) to unlock the device.

the .rst security barrier has been breached.


Projects in the field of big data ISM are actively implemented by the leading manufacturers of IT products and systems.

the results of IBM research are implemented in a series of InfoSphere Guardium products to protect structured and unstructured data in real-time and offline mode.


FrSIG covers six kinds of security levels, i.e., combination of two levels of unforgeability and three levels of anonymity.

(uf , anon) represents a security level as uf is parameterized by eUF and sUF, and anon is parameterized by basic anonymity, anonymity against attribution attacks and anonymity against full key exposure.


As information .ows from one container to another, thepolicy is also propagated.


2.3.4 Availability Data transmission over ad-hoc wireless and sensor networks as well as unprotected radio-frequency identi.cation (RFID) tags are known to be vulnerable to active attacks such as tra.c analysis, spoo.ng and denial of service [28, 27].

limited bandwidth of the ad-hoc communication networks that are used in ubicomp applications exposes such systems as targets for denial-of-service attacks.


The attacker in this model is static as in [7].

it chooses S * and obtains the keys for identities outside of S * , before it sees the public parameters PP.


In that setting, the computational parties do not have access to the private inputs and it is essential that they do not learn any information about the data they process, while still being able to correctly carry out the required operations.

the computation needs to be data-independent or oblivious.


OVERVIEW OF VOIP NETWORKS SIP, by the virtue of its design, operates on a truly end-to-end basis.

if the end points of any particular session are known to each other, then a SIP session can be established entirely between the end points, without any support from the network infrastructure.


As of April 20, 2010, 54,429 of the retested devices are still publicly accessible, out of which 52,661 devices remain vulnerable.

approximately 96.75% of accessible vulnerable devices are still vulnerable after a 4 month period, and factory default credentials have been removed from only 3.25% of the same set of devices.


Then, the tree is dynamically built and expanded as the phase proceeds.

a negotiation tree NT is a tree in which each node corresponds to a term, and edges correspond to policy rules.


The key elements of our experimental set-up were the same as in [10].

we used the same anomaly detection systems, namely, PAYL 1-gram and 2-gram, as well as the same attack and same traf.c datasets, as in [10].


It is thus dif.cult to precisely locate f, c, or the conditional branch in the target disk, and corrupting them raises OS integrity alarms that can render the system unusable after rebooting.

directly tampering at the OS and user-level can lead to easy detection by the target computer.


Though the router incident to a bottleneck link can deliver enough information for a deployed router to adjust .ow rates, this approach requires the router incident to the bottleneck link to do some work.

it still requires some level of deployment.


How exactly can it be translated to the domain of security7 How do we define different parts of the model?

how do we decide which actions are active failures, and which are latent?


A di.erent way of slicingisknownasapplicationcommunities[22]: assuming a software monoculture, each node running a particular application executes part of it in emulated mode.

applications are sliced up in the spatial domain and adistributeddetectoris needed to cover thefull application.


Di.erent from the policy model used in this paper, they assume actions in provisions and obligations are disjoint from those requiring privileges.


introduced additional leakage functions: L3 and L4 in their paper.

for additions L3 leaks a deterministic function of each keyword in a ciphertext.


Goldreich states in [16] that although the general secure multi-party computation problem is solvable in theory, using the solutions derived by these general results for special cases can be impractical.

e.ciency dictates development of special solutions for special cases.


guarantee that every script executes and travels in its accented form.


As we are in the public-key setting, it is worth noting that adversary A =(A1, A2) is given the public key upk and so can encrypt any message of its choice.

the adversary can mount chosen-plaintext attacks (CPA).


The algorithm sets s1 =4 (line 10), since I1 = {9,10,11}, Field(9) = [4,5] and Offset([4,5]) = 4.

4 is the smallest offset accessed by instructions in I1.


It is seen from table 1 that OEPE method obtains the largest embedding capacity and PSNR value, which indicates OEPE method keeps most comparability between the original and watermarked image while the most watermarking information is embedded.

oEPE method realizes best tradeoff between transparency and payload.


The second principle is the notion of groups within groups .

in a given g-SIS system, there may be any number of groups.


EVALUATION To evaluate our proposal, we performed a wide range of experiments.

we investigated the performances of all the presented basic methods (cfr.


First, the attacker is able to notice exactly when a new page is requested.

the attacker knows which sequence of packets corresponds to a single page.


POLICY SIMILARITY Before introducing the policy integration preferences, we need to analyze the behavior of the policies to be integrated with respect of the requests they authorize.

we need to determine whether there are requests authorized by a policy and denied by another.


Easy adoption: HTTPi should .t seamlessly into the current web infrastructure.

the design should be transparent to the intermediate web servers (such as CDN servers and HTTP web proxies) and should involve minimal changes to servers and browsers.


The bitmoving algorithm minimizes the total transmission power.

users whose QoS is not met will be allocated more bits.


The above computation raises an interesting technical point in that the comparison must be performed correctly even if one or both of the scores have no contributions and are therefore 0.

if a physician j1 has no ratings for condition k, both rj1k and wj1k are 0 (and thus s .


The strength of our mechanism relies on the enhancement of the known audio/image/video watermarking algorithms [7, 10, 11, 17] with the usage of a semantically secure watermark as in the case of compressed audio watermarking algorithm [13, 14].

instead of using a simple bit sequence as a watermark, we apply a semantic watermark which is a bit sequence that represents a certain combinatorial object with a specific characteristic known only to its creator.


For this purpose, we model security scenarios by using defense trees (an extension of attack trees) and preferences over countermeasure using Conditional Preference networks (CP-nets for short).

we introduce two di.erent metho ds for the composition of preferences: the and-comp osition and the or-comp osition.


For this purpose, ARBAC97 uses role ranges and prerequisite conditions.

prerequisite roles are used as user and permission pools for administration roles.


Besides o.ering secure storage, the Vault also ensures state continuity [24].

protection against two possible attacks is provided.


Furthermore, it is also a passive processor.

it cannot read or write directly into memory or other devices, and cannot do anything unless the CPU requests it.


We chose to work with four prime factors for ease of exposition.

one could imagine using a prime order group and specifying several subspaces VR which are orthogonal to each other.


The attacker .nds the .rst possible attack and tries to execute it because there is no knowledge of how easy the attack is.


We interpret terms in the free algebra, i.e., syntactically di.erent terms represent di.erent values.

two di.erent constants always represent di.erent entities.


Different from the prior arts, the evaluation results further trigger autonomic trust management based on the sub-model of trust management (ATM) in order to ensure and sustain the trust relationship [12].

tR and CTM can be used to compare trust relationships for auto-configuring a set of components that could cooperate with each other in order to provide expected services.


In this context, an emerging trend is the integration of smartphones into modern automotive systems and applications such as access control to unlock, con.gure and start vehicles [41, 39, 47].

the NFC interface is well-suited for such applications due to its short nominal communication range (of a few centimeters) providing basic assurance of the user s physical proximity.


By not only directly observing the bot clients but also the reconstructed botnet C&C server, we were able to wear the shoes of the botmaster and were thus able to identify some of the performance and design challenges that botnet creators and botmasters must face.

what would have been a textbook solution to ensure data con.dentiality and integrity, i.e.


The algorithm writes a vector of the standard basis as a sum of an even number of samples; next, this is extended to an odd number of samples, as it is required by the attacks of Section 5.


The attacker can even consider system call traces that could not possibly be output by any execution of the application, so long as those traces will be accepted as normal by the IDS.

the attacker can examine the set of system call traces that won t trigger any alarms and look for one such trace where the malicious sequence can be safely inserted.


We remind that we are in the honest-sender setting.

the sender does not encapsulate fake or wrong identities.


Namely, when data remotely measured by patients is used by tele-health services or in the medical professional world, healthcare providers need to place greater trust in the information that patients report.

in order to make sound medical decisions based on this remotely measured biomedical signals, they have to be ensured that a measurement contains as little noise as possible, the amount of noise being an indication of the quality of the signal.


Unfortunately, while this process prevents explicit misuse of participants DNA data, it turns out to be insuf.cient for deterring information leaks in a more implicit way.

this paper reports a surprising .nding of our research: even the test statistics computed over a small set of SNPs, like those routinely published in GWAS papers, could reveal a substantial amount of genetic information about participants, and even lead to disclosure of their identities.


If num(i,Xj) is not larger than the number of the corresponding pixel value i in S -i.e., num(i,Xj) = .i .i=0,1,··· ,255, then all the ciphertexts of block Xj are di.erent from each other, no matter their plaintexts are the same or not.

the encryption procedure of our  (a) (b)  (c) Figure 2: The function of RandPermut([Sß ]).


(attr, P ub) form a simple policy, and sig is the signature on both attr and nym made with the secret key corresponding to the public key P ub.

the CA issues a credential asserting that nym has attribute attr by providing sig to the owner of nym.


We aim for a level of security comparable to that provided by authentication systems using a four-digit personal identi.cation number (PIN).

an impostorshouldnotgain accesstothesystemwithaprobability higher than 1/10,000.


[12] have suggested that it may result in an overoptimistic estimate of the malware clustering accuracy.

limiting the reference clustering to samples for which a majority voting-based consensus on the family label can be reached, and discarding the remaining ones, may reduce the reference clusters to only include easy to cluster malware samples (i.e., clear-cut cases of malware samples that are very similar to each other) [12], thus potentially causing the accuracy of the malware clustering results to be largely overestimated.


Because of the inconsistency of the Kaspersky labels (some Kaspersky label groupings, such as the jorik family, represent a very diffuse range of malware, whereas others, such as webprefix represent a very specific set of variants) we heuristically selected four Kaspersky defined malware classes that we believe share a similar range of behavioral traits.

we selected the xtoober , jorik and vbkrypt families, alongside a random selection of malware samples Kaspersky labeled as unknown samples.


The available services are grouped together into a socalled community.

services in the community share a common set of actions S, the actions of the community.each available service in the community exports its behavior to the community itself in terms of the actions in S (the actions recognized be the community).


They pointed out that many prior proxy re-encryption schemes (before their paper) cannot satisfy the intuition of anonymity: an adversary cannot learn identities by observing su.cient ciphertexts (before or after re-encryption) and re-encryption keys, even it colludes with some corrupted users.

for any probabilistically polynomial time adversary, it cannot distinguish a valid re-encryption key for a pair of users, from a random one selected from the re-encryption key space, although it can access re-encryption key generation oracle and re-encryption oracle (perhaps decryption oracle additionally).


Note that, for building the access activity model, we do not require any knowledge about malicious processes.

the model is solely built from generalizing observed, good behavior.


For example, PIO overlapping is similar to the PIO con.guration space attack, but in this case the attacker can only recon.gure the con.guration space of a speci.c device she controls.

by changing the PIO BAR register of a directly assigned PCI/PCIe device, an attacker can overwrite the BAR value with the one of another device attached to another VM.


Completeness: Do not let any infection stay at-large.


When moving from .ner to coarser levels, the coarser level subsumes results from the .ner elements.

an auditing company wins whenever, for example, a speci.c penetration test succeeds.


WATCHER -This is a secondary thread that manages: a) The Qemu-KVM startup; b) The registration of the Qemu-KVM pid into KvmSec; c) The abnormal termination of Qemu-KVM;  Communication channel with Qemu: Since both the DM and the Qemu processes are executed in userspace, we can use any of the Linux System V IPC facilities for Inter-Process Communication.

we chose to make use of a named PIPE (or FIFO).


This is a botnet architecture that uses social networking based steganographic channels for command and control.

image steganography is used to achieve this goal.


The primary goal was to reduce and bound the TCB of a Xen-based system, in order to improve its security.

by removing Dom0 user-space from the TCB, we would remove the requirement that the administrator of the physical platform be trusted.


Charlie then creates a signature of the con- catenated value of el and E¢(d211IDA).

sigc (el lIEs (42 I IIDA)), where Sigc(.)


Returning to the body of the loop, the next step is to make sure that for every Pi (line 3) its threshold check (Figure 4) will not reject Pj .

given the query q and the estimated knowledge of Pj, we make sure that the answer to the query will not reveal too much about Pi s secret xi (where by too much we mean Pj s certainty about Pi s possible secret exceeds threshold ti).


Typically, new paths and nodes may appear in View and the node ordering may be different from the Source one to prevent inference.

view represents the total amount of information a grantee can gather by subsequent queries.


We use partitioning for a somewhat di.erent motivation than described in the SSS paper [31].

the SSS construction relies on partitioning mainly to get rid of oblivious sorting [11, 12], thus achieving a constant factor saving in bandwidth.


In this paper we present our initial work on an axiomatization of privacy and utility.

we study how these concepts are a.ected by randomized algorithms.


A policy language which introduces a decision to indicate the occurrence of errors in the policy evaluation process is XACML v2 [1].

xACML v2 uses decision set {Permit, Deny, NA, Indeterminate}, where Permit represents the permit decision, Deny the deny decision, NA represents that the policy is not applicable to the given query, and Indeterminate indicates that the policy decision point is unable to evaluate the query because of some error (e.g., missing attributes, division by zero, network errors while retrieving policies, syntax errors in the query or in the policy).


Such a generalization is important as it opens doors to much broader information sources for trust decisions, including organizational LDAP directories, role databases in RBAC, and audit trails generated by intrusion detection systems.

feedback reports and ratings in online communities and P2P systems are a special form of credentials as well.


We argue that the lack of a consistent de.nition of an insider hinders research in the detection of threats from insiders.

a de.nition of an insider is .rst required in order to ensure that the research is, in fact, detecting threats of the desired type.


We think its core concept lies in the membership grades given to a data point for each group, and thus the concept could be effectively utilized in our instance selection task from unsupervised data for network anomaly detection.

we will extend current FCM algorithm and use it to select the most valuable and representative data from the normal training data for efficient network anomaly detection.


To compute the public key pk, the CC computes the modular multiplicative inverse of sk by using the extended Euclidean algorithm.

the CC computes d such that sk * d = 1 (mod .(n)).


2.4 Reliability Requirements In addition to patient security, physicians must also be protected from unreasonable users or dishonest competitors.

a small group of users should not be able to sabotage a physician s reputation.


2.3 Hardware IOMMU To improve the isolation, performance, and security of I/O devices, hardware supported I/O Memory Management Units (IOM-MUs) were introduced [26].

intel VT-d [27] provides hardware support for DMA and interrupt virtualization.


The essence of this platform is precise heterogeneous replay.

we record malware execution using hardware virtualization for transparency, and then replay and analyze the malware s execution using dynamic binary translation for .exibility and ef.ciency of indepth analysis.


Step 3: Generate Constraints for Candidate Roles.

we take con(r) to contain every equality that holds between every assigned user and every assigned permission of r. for each attribute au in AU and each attribute ap in AP , we add the equality au = ap to con(r) i.


Then, there is a better chance for criminal hubs to successfully allure other criminal accounts followers to become their own followers.

these followers have been already proved to be more susceptible to follow criminal accounts, which many legitimate accounts may not choose to do.


Our protocol gives authorization for a set of services that is fixed at the time of user registration, whereas in some cases it may be desirable to give users access to a set of services that is only logically identified when the user registers and whose membership may change at run-time.

we do not provide a mechanism for revoking access to particular services in this model.


FRAMEWORK OVERVIEW AND THREAT MODEL 2.1 System Framework Overview The basic requirement of OS kernel integrity protection problem is to control accesses to sensitive kernel objects (e.g., the kernel text, the system call table, the interrupt descriptor table) in a real-time manner.

authorization decisions should be based on the real-time attribute values of requesting subjects and target objects.


4.2 Changes for Precise Replay Considering all these challenges in software emulation and dynamic binary translation, we come up with several design changes in the work .ow of software emulation to ensure precise replay.

we have modi.ed the implementation of dynamic binary translation in QEMU to comply with these design changes.


Since PKIs operate over a possibly untrusted network, the adversary, in the worst case, can control the network.

we assume that the adversary can eavesdrop, modify, and insert messages at will.


Since the Random Value is generated by the strawman router,a matching pairof RandomValuesin the packet andin the router s local memory implies that the previous packet was successfully received and acknowledged.

the receiver and the sender collaboratively acknowledge to the router that the RandomValue and the packet therein were successfully received.


While traditional encryption schemes can provide con.dentiality, they do not hide the data access pattern which can reveal very sensitive information to the untrusted server.

the blocks accessed on the server and the order in which they were accessed is revealed.


We design novel constructions for a collection of fundamental problems over streams represented as linear algebraic queries.

our basic schemes authenticate dynamic vector sums and dot products, as well as dynamic matrix products.


This panel will examine the issues surrounding the role of the media and privacy.

it will examine legislative and self-regulatory models governing the behavior of the press.


More rigorous government information assurance examples include the Common Criteria (CC) [1] standard ISO/IEC 15408, a framework in which computer system users can specify their security requirements, vendors can then implement and / or make claims about the security attributes of their products, and testing laboratories can evaluate the products to determine if they actually meet the claims.

cC [1] provides assurance that the process of specification, implementation and evaluation of a computer security product has been conducted in a rigorous and standard compliant manner.


A PIP is a program that runs on two or more platforms without change.

we formulate and address the PIP generation challenge.


The propagate idiom is the default failure handler used in BelLog speci.cations.

we need not explicitly encode it using BelLog rules.


The two clusters are expected to distinguish imitating attackers from genuine users.

based on the discussion above, the smaller cluster is considered to be attacker cluster (line 12 16).


This paper focuses its attention into an approach to modeling system-centric information in order to facilitate RE process.

it .rst discusses the general informational characteristics in RE and two informational .ow types among authorities involved in RE, forward information .ow (FIF) and backward information .ow (BIF).


> 13% of peers), our cooperative of 30 peers avoids a false positive.

a high rate of recognition (m/n) does not imply  non-worm Figure 5: Average and maximal rates of recognition for non-worms whose average rates of recognition exceed 1%.


Let V iewB((p, s), t) be a random variable representing Bob s view during the real execution of SPH-PSM.

we say that SPH-PSM guarantees Alice s privacy if there exists a Probabilistic Polynomial Time (PPT) algorithm B* such that, given Bob s output b, the following holds: {B * (t, b)}((p,s),t) =c {V iewB((p, s), t)}((p,s),t) for all possible inputs, with the knowledge of the output bit b and Bob s input, B* can e.ciently simulate the view of Bob.


(2) The inference of the assignmentsbetween business roles and technicalrolesis very conservative.

for indi.erent biclusters without substructure, the assignment ukl between the usergroup k and the permission-group l is 0.


In [7] we considered the relative performance of various queue management strategies with respect to maintaining this QoS measure.

since illegitimate connection that make it to the queue never get completed (e.g.


The injected code needs to be compatible with the execution environment for these attacks to succeed.

the attacker needs to be able to talk to the target system in its own language .


The proposed protocol must be secure against passive and active attacks.

it must not allow active or passive attackers to learn the key exchanged between two paired devices.


In this paper, we present a proxy-based public key infrastructure that allows LBS mobile users to shield their identities using pseudonyms and protect their communications using mediated identity-based encryption.

we propose the .rst identity-based signature scheme applicable in a mediated environment.


5.2 Experimental Identi.cation of relevant State Information We introduced the notion of a pro.le in De.nition 5 abstractly as an aggregation of views.

a pro.le may consist only of the last view as-is, but may also contain accumulated information from a series of consecutive views of a system run.


3.3.1 Random False Data Injection Attack With the resources to compromise up to k meters, the attacker may use a brute-force approach to construct an attack vector.

the attacker may try all possible a s consisting of k unknown elements and m - k zero elements.


Cleverly attacking companies might go a long way before being detected.

if they provide excellent business service, they might have excellent reputation scores while being your biggest threat.


An essential insight was that the database could consist of short sub-strings that may occur in a trace.

consider each sub-string of length N (commonly called N-gram) of a trace.


which are challenges for future standardization but outside the scope of this paper.

we used in this paper some information sources from Wikipedia and other newspaper channels because they are the first-hand materials related to our study and also because of the lack of serious research publications or the state of the arts reports regarding this topic so far.


On the other hand, the security requirements by eCK actually cause the eCK-model less applicable than the traditional CK-framework.

any DHKE, where the session-key can be derived from the DH-exponents that are speci.ed as the session-states (e.g., IKE [49] and SIGMA [50], STS [32], SSL [35] and TLS [30], and JFK [3] and much more), cannot be proven secure in the eCK-model.


The users that assigned to a temporal delegatable role, a .xed delegatable role and a regular role are exactly the same if these three roles are in the one-to-one relation.

a pair of (regular role, .xed delegatable role, temporal delegatable role) will be used as a single role in user-role assignment.


In order to get from the isolated model, in which each consumer of identity information manages this information himself to an identity management which takes the decentralized nature of the Internet into account, we argue that consumers of identity information need to be able to assess and distinguish the quality of the information they receive.

with regard to the launch of electronic ID cards as fostered by several european governments, di.erent sources of identity information will have a di.erent quality in terms of correctness and integrity.


In Chapter 5, we concentrate on browser-based protocols and derive technical consequences from the privacy requirements.

we present design decisions that are mandatory to fulfil the privacy requirements.


INTRODUCTION In 2001 and 2004, Hannu Kari of the Helsinki University of Technology provocatively predicted that the Internet would collapse by 2006 due to being completely overrun by malicious users [19].

users dissatisfaction with the state of security on the Internet would be so high such that they would abandon it [6].


5.2 Simulation Setting We simulated different node captures, varying the captured node and the capture time.

starting from 100,000 seconds after the network deployment, we have considered the events split in 13 intervals of 6 hours each.


A UAS is a set each element of which is a set of roles that can be activated in a single session by a specific user.

a user assigned to a role in a hierarchy can activate only those set of roles that occur in a UAS associated with him.


Thus, we formulate the problem of emulating the malware sample as constructing an emulator that behaves as the sample expects with respect to the anti-emulation check, but is otherwise unchanged.

this modi.cation Eel of Ee satis.es f(Eel ,I)= f(Er,I) (the anti-emulator check is fooled), even though g(Eel ,I)= g(Ee,I) (the environment is otherwise the same).


x The input ACL is run through a lexer and a parser that performs a minimal translation between the grammar de scribed in Section 3.4 and the Perl-like syntax expected by the .NET regular expression library.

the translation must interpret wildcard tokens ( !


As a result, that tag is not able to respond to a further query from a legitimate reader.

a genuine reader cannot communicate with its legitimate tags.


The easiest way to exploit this structure is for the recursive construction of the G structure to stop as soon as its corresponding sub-grid consists of cells that all have the same key.

step 1 of Data Struct Build needs to contain a termination test for when all of the mn cells share the same key (in which case it stops even if n > 2).


Consider how this algorithm works for the set of events shown in Figure 3a (Figure 3b pictures the log of events as a complete dependency graph): GraphGen is initialized with the detection point, which is .le X at time 10.

the administrator knows that .le X has the wrong contents by time 10.


The key property of our schemes is that it is possible to identify a personalized decryption software.

it is possible to trace a given implementation or a copy thereof.


One important observation about our .tness function is that it is ground-truth agnostic.

we need not assume that a CAPTCHA must be solved correctly by nonattackers.


In this attack, the attacker intends to construct an attack vector a such that the resulting estimate x bad = x + c,where c =(c1,c2, ..., cn)T and ci for i .Iv is the speci.c error that the attacker has chosen to inject to xi.

the attacker wants to replace xi1 , ..., and xir with xi1 + ci1 , ...,and xir + cir , respectively.


However, in the Bell-LaPadula model the criterion is universal the security label of a subject must dominate every part of the security label of an object.

if we de.ned the security level of a permission to be R(p), we would require that R(p) R(u), where this order inequality is interpreted as .R(p) ..R(u).


Since e was not removed, it belongs to both Gu and Gw.

j is not iteratively expensive with respect to either u or w. As before, since i .


Very closely related to the non-binding nature of this pattern is the lack of guest portability.

if the guest system software is changed or replaced completely, the software architecture descriptionmust alsobechanged tore.ect this and the view-generating function must be constructed anew to accommodate the new system software.


Such collusion increases the average detection error, since honest nodes use all the values provided by bad-mouthing nodes when they compute the indirect trust in sel.sh nodes.

when the number of bad-mouthing nodes is higher than the number of sel.sh nodes, as shown in Fig 0.9 ure 7, the average error decreases when the number of dishonest nodes increases.


When applying the PIP list derived from the Hotmail log to the Windows Live ID sign-up problem, we detect more than 3 million bad accounts right on the day of their signups with 97% precision.

over 77% of the detected bad accounts are registered using non-PIP addresses (§5.1).


The data PX has the property that, from PX and another biometric template Y , the original X can be recovered, provided that Y is close to X.

pX can be used to remove the noise from Y , if Y is close to X.


The Mac version of the product does not have feature parity with the Windows version; however, ITSG was most concerned that the product met a specific set of requirements, not whether it was the best or the most full-featured Mac based whole disk encryption product.

pGP Desktop for Macintosh was not rated against competitors or against the Windows version.


Nevertheless, our .ndings about challenges in IdM process before deployment of the IdM solution corroborate their key .ndings.

they identi.ed a set of challenges that we also observed in our case study: management of exceptions, getting noti.cation about policy change (employees leave the organization or change their department), getting updated information about who is responsible for a resource, verifying requests, keeping records, and choosing a usable access control management interface.


Thus, imprecision in the lyzes loop bodies exactly once.

it ignores back-edges of results of the analysis will mean manual intervention to determine loops.


In response to a command, the counter must produce a veri.able output message that certi.es the output and the execution of that command.

if a user invokes a command cmd(t) on the counter at some real time t and then subsequently receives a corresponding output response message Out(t) from the counter, there must be a veri.cation algorithm that the user can follow to check Out(t) and convince himself that the counter has in fact executed cmd(t),and that Out(t) is indeed cmd(t) s correct output.


(int .int) Accordingtothistype, C should provide a proof of (B says Do(o)) .Do(o) The reference monitor can then try to establish Do(o)for itself, in this case by proving B says Do(o).

the reference monitor may simply assume B says Do(o)if it has authenticated the caller as B.


We have given two e.cient algorithms for the dynamic model-checking problem, supporting the feasibility of running implementations of our framework on devices of limited computational and storage capacity; a useful property in global computing environments.

it is noteworthy that principals need not store their entire interaction histories, but only the so-called active sessions.


Middleware provides tools to manipulate uniformly heterogeneous components running in a system.

the proposed system focuses on three main areas: flexible solutions for context-centric access control, active context view provisioning to mobile users, and privacy support in the propagation of user context information.


For example, to measure H(a) would require an aliasing analysis to know what addresses a could have pointed to, and a calculation of the joint entropies between all values that could have been loaded and the taint source.

equivocations for address dependencies occur when there is not perfect entropy in the range of values that could have been loaded or stored, due to limitations on the address or redundancy in the values in memory.


As the fault is in emulation mode, we have known the fault location.


{b'id In a hybrid run, Hand Areceive the same messages, but with a different distribution.

the session key is not drawn at random from {0,1}kbut is the sum of the n-tvalues .


There is a good reason for this, since benign samples typically contain much more ob jects (e.g., text, images and so on), with respect to malware samples.

malware samples in the wild typically contain only objects that are necessary/useful to execute an exploit.


Speci.cally, it is the smallest time found in any triple in ST Z1 Z2 - (Z1 Z2).

the earliest scheduled time for any upcoming event which is in either Z1 or Z2, but not both.


In this paper, we exploit public data available on Facebook to infer users undisclosed interests on their pro.le pages.

we infer their undisclosed interests from the public data fetched using Graph APIs provided by Facebook.


The mapping between the input CSI samples Cu,s and user pro.le Cu,s is constructed in the form of the kernel function Kernel(·, ·), such as Kernel(Cu,s,Cu,s )=FT (Cu,s)F(Cu,s ).

we choose a polynomial kernel as the mapping function and the problem in Equation 6 can be expressed as: S Sl 1  max{ as- au(yu,syu,s Kernel(Cu,s,Cu,s ))as } as s=1 2 s=1 s =1 subject to the constraints: (8) S as = 0, asyu,s =0, (9) s=1 where as is the Lagrange multipliers associated with equation 7.


Probing the kernel closely models the performance of a virtualized environment as probes also result in a trap when execution reaches the probe, emulating the behavior of a virtualized environment.

we use jprobes and kretprobes [21], which allows us to get a handle to the probed kernel function arguments and return values respectively.


Note that one policy implication is immediately apparent, In those regions where .V/.S<0 it makes sense to attempt to change the state space, perhaps by educating users, rather than to increase security.

while we have taken Security Use Sensitivity to be given, it may in fact be subject to influence.


HIERARCHICAL DATA MODEL AND INTENDED PURPOSE LABELING As in [3], our access control model is based on purpose metadata associated with data objects.

every data object is tagged with intended purpose labels, and the data access is controlled according to these labels.


r2 | r1; r2 | r * | f?, where P is an atomic proposition in P , r is a regular expression over the set of actions in A ,and a is an atomic action in A .

pDL formulas are composed from atomic propositions by applying arbitrary propositional connectives, and modal operators ( r) f and [r]f.Formula ( r) f means that there exists an execution of r (i.e., a sequence of actions conforming to the regular expression r)reaching a state where f holds; and formula [r]f is intended to mean that all terminating executions of r reach a state where f holds.


In general, all three of these aspects are interrelated and, ideally, they are in agreement.

the algorithm should solve the formulated problem in that it returns the best possible result as de.ned by the quality measure.


3.2.2 DynamicTimeWarping Similarity (DTW-S) The Dynamic Time Warping Similarity (DTW-S) [5] uses for comparison an adaptation of the classical DTW algorithm.

instead of giving as a result a distance measure, this method gives as output a percentage of similarity between the two series.


Not only does this delay detection to Epoch 225 in our case, but also note that whether or not a new worm s .ngerprints ever correspond to the most frequently occuring set depends upon the relative rate with which the worm packets appear during the time window captured by the distribution.

if the rate of Witty worm packets remains below that of the Slammer worm, detection mechanisms that analyze the most prevalent .ngerprints will not yield good results.


These include parameter and results caching meth Communication Path  ods to avoid frequent accesses to backend servers, request redirection and scheduling for load balancing or to di.erentiate service levels for di.erent end users [1], and request duplication or partitioning to service complex requests or to attain high levels of reliability [13].

the actions and communications explicitly carried out by applications are subject to a myriad of implicit controls to gain performance or reliability advantages.


(6) sli..i  3.3 Equilibrium Analysis Based on the de.nition of NE (De.nition 2), each controller plays her/his best response strategy in an NE.

no controller has any incentive for changing her/his own strategy while the other controllers .x their strategies.


The CS is modelled as honest-but-curious (as considered in state-of-the-art on data outsourcing [22,36]).

the CS is trusted to honestly perform operations requested by the DBUs according to the protocol speci.cation.


by changing the key update procedure) and studying its physical implementation in various devices are typical examples.

an interesting question is to determine the minimum architecture size (e.g.


CONCLUSION In this paper we propose a new biometric measure for users of smartphones.

we focus on the movement that a user performswhen answering(or placing)aphonecall,andweinvestigate whether this movement can be used as a biometric authentication measure.We propose four basic methods(leveraging different sensors available on the phone and several similarity algorithms).


In order to reduce collision probability below 0.5, for any network size, CW size in each station must be larger compared to network size.

for better throughput performance, the number of competing stations on network should be well below the operating CW sizes.


The initial state information for the corrupted parties is given ~o the adversar3~.

the adver- sary is static, which simplifies the protocol presentation.


All role names that appear in the  of the Role  should be delegated roles.

their roleType should be set to delegatedRole.


2 X (p(c) - u(c))2 .= (4) u(c) c.C This statistics also has the property we need.

when the two distributions are identical, the value is 0.


Thus, we have a set of candidate attribute-value pairs, cau r for every user {ui,uj,uk ... } who is assigned to role i r. The union of these sets is the candidate role attribute set cau r for role r. Some of the individual attribute-value pairs sets will be exactly the same.

some users assigned to role r are likely to have exactly the same attributevalue pairs, cau i r .


3.1 System Details In this section, we illustrate the details of our approach.

we describe the states of our Markov models, how the states are combined together to generate signatures, and how the signatures are matched to classify webpages as malicious or benign.


If we have two sets, S1 and S2, and |S1| = |S2|, then we say that S1 is denser at n-bits if |Cn(S1)| < |Cn(S2)|.

if the total number of n-bit CIDR blocks containing S1 is smaller than the set containing S2.


This property is preserved over all constraint reductions in the proof.

we cannot unify payload with non-payload subterms.


In particular, this is true for the analysis of false positives.

authors collect traces only for a small set of benign applications.


3.3.3 Enhanced compressed DFA-based solution We want to overcome the main limitations of our compressed-DFA design.

we want to reduce warp divergence and thread underutilization.


attribute-based encryption(ABE)[1,8,10,18] enables encrypting events, such that they can only be decrypted by parties thatpossess the corresponding attributes.


The TVMM provides basic services, such as support for running multiple, isolated VMs concurrently, but the management VM is responsible for higher-level resource allocation and management.

the management VM allocates memory and disk space to VMs, and controls VM access to physical and virtual devices.


We propose desiderata for good protection schemes.

we argue that the protection scheme should not only be able to prevent inference but also be able to guarantee the success of trust establishment as much as possible.


On the other hand, we cannot simply provide an equa- N N tion such as ReplicatedSystemi because this implies ini=0 dependence in the failure of each system including the interaction of subsystems in their environment [20].

one can imagine that for some 0 = j,k < N and j = k; ReplicatedSubSystemj causes ReplicatedSubSystemk to be less safe, or indicate a less safe system.


On the other hand, the result of Lemma 1 is applied to solve the problem in a convex fashion.

problem (14) is recast with p1,...,pK as the variables, i.e., minimize -t (15) p1,...,pK ,t N ainpi subject to t -=0,i=1,...,Kbin + pi n=1 K pi =Pmax R , i=1  which is a strictly convex problem, and can be solved by any standard convex optimization algorithm.


However, session key distribution in [27] requires that any coalition of at most t valid group members cannot get any information about another member s personal secret, while De.nition 2 in our paper requires that the uncertainty of such a coalition to determine another member s personal secret is at least b bits.

session key distribution in [27] doesn t allow any information leakage, while our De.nition 2 allows certain information leakage as long as the uncertainty of the secret is at least b bits.


In this paper we explored these risks in depth from an image repository perspective.

we analyzed the risks faced by administrators and users (both image publishers and image retrievers) of a cloud s image repository.


9,826 (33.8%) of the analyzed malware programs exhibited insuf.cient progress at some point during the analysis.

at least one of the heuristics triggered.


CONCLUSION AND FUTURE WORK In this paper, we clearly address the user authorization query problem of RBAC systems that include hybrid hierarchies and DSoD/cardinality constraints.

this relates to the issue of processing user s requests for a set of permissions or a set of roles within a single RBAC session.


(The reader can refer to a recent overview of SMC [10], or a textbook-level treatment [6].)

by running a distributed protocol amongst themselves the parties can learn the desired result f(s1,...,sN )(or, in the general case, each party Pi learns the result outi) while ensuring that no information about other party s input is revealed beyond what is implied by the result(s).


Another key issue overlooked in [8] is that the notion of IVP does not address the case in which the veri.cation of data fails.

it is not clear what actions need to be taken when the veri.cation procedure fails to con.rm that a data item is in a valid state.


When a user joins or leaves the group, remaining members should not be a.ected.

join and leave operations should be completely oblivious to other members.


We expect that attackers will employ a channel changing strategy.

the attackers will either try to .nd the channels the network nodes are currently using and attack those channels, or simply attack channels according to a pseudo-random sequence.


However, the attacker shall not be able to subvert or replace the authentic access point.

the attacker cannot manipulate the access point s light, which can be external to the access point, in any other way than by manipulating the communication channel.


The TPM user can (for example, through faulty code) cause the TPM to run out of a certain kind of available resources, thus preventing any operation that requires creation of new objects of that type.

we discovered that some TPMs failed to release authentication sessions when certain GetCapability functions fail and quickly run out of sessions.


Gi+1) = 1/C(d), where Gi is the i-th reported region and Gi+1 is the subsequent reported region.

he never leaves the gray region adjacent to the initial square in the above mentioned .gure.


We note that a user can potentially draw inferences on tuples that she cannot access only when such tuples have index values in common with other tuples that the user can access.

there can be inference whenever there are plaintext tuples that have the same value for at least one attribute and can be accessed by di.erent, but overlapping, sets of users (i.e., the tuples have di.erent but overlapping acls).


We argue that many of these contexts are congruent to other contextaware ubiquitous computing applications.

we present a context-aware access control model for healthcare informatics.


The polynomial function f in the veri.cation query Qi will take values on a subset of Zp of size = (p - (i - 1)f)/f as deg(f) = f. Thus, A can correctly guess the output of f with probability = f/(p - (i - 1)f).

qi will be a valid type 2 forgery with probability at most e f/(p - (i - 1)f), i.e., Pr[Yi 2|Bi-1] = .


This suggests that participants intuitively know which questions uncover more information about their passwords.

as mentioned in Section 4.6, participants were especially unlikely to answer Q14 (what symbols), which reveals the most information about their passwords; and especially likely to answer Q18B (contains year), which reveals the least information about their passwords.


- log2 max(|aut(C)|, |aut(S)|), where |aut(G)| denotes the number of automorphisms of graph G. We derive an upper bound on accuracy that may be achieved by any de-anonymization algorithm using the number of graph automorphism.

if the social network S has |aut(S)|automorphisms and contact graph C has |aut(C)| automorphisms then the accuracy of any de-anonymization algorithm cannot ex .C .S ceed min(1 - , 1 - ), where .S is the smallest natural |VC ||VS| number such that .S!


Naturally, people would like to make their private data only accessible to authorized users.

di.erentiated data access is frequently required in the sense that users with di.erent attributes or roles should be granted di.erent level of access privileges.


These permissions are neither granted too early nor revoked too late , ensuring in this way a tight matching of permissions to actual usage and need.

the granting, tracking and revoking of permissions are automated and synchronized with the progression of associated tasks.


Further, in an ideal taxonomy the axes of the lattice would be orthogonal from each other, but we can see that our current axes are not.

we have seen an interplay between the Decision Mode and the Enforcement axis: in the systems with Centralized decision mode, there exists the potential for a network failure where the central server is inaccessible, and so a service will default to fail-closed rather than possibly improperly service a request that limits the implementation to total prevention on the Enforcement axis.


On the contrary, orientation sensor has never been used before our proposal.

our proposal leverages both accelerometer sensor and orientation sensor.we implementedaproofofconceptofour proposal for the Android system.


This is accomplished by having each ciphertext include a MAC in each encryption layer.

the (i + 1) st eneryption layer of a given input includes a MAC employ- ing a key derivable by server Si+l from the compressed key schedule.


For backwards compatibility, we chose not to serialize taint information.

we wanted to ensure that a web application with taint tracking enabled would still be able to read data it might have serialized earlier before taint tracking was enabled and vice versa.


Let Blockl(x, i) denote the ith block of length l of the binary string x.

blockl(x, i) is bits (i-1)·l+1 to i · l of x.


To mitigate these issues, in this paper we want to study to which extent it is possible to enrich the information collected during malware execution to make the experiments repeatable and achieve full network containment.

we experiment with a protocol-agnostic technique [20] previously adopted to model the attack tra.c in high-interaction honeypots [18, 16].


Even though some of them are subtle, hiding deeply inside the systems, they can all be exploited in practice through carefully-crafted attacks, which often cause serious consequences.

we found that an unauthorized party can circumvent security checks of GCM to preempt the registration ID of the victim s app.


Similarly, when single-path symbolic execution is applied to test case generation toincrease coverage, itwillbe unable(in one iteration) to generate an input that forces execution down a different branch than in the original execution, if taking that branch is only feasible with a different number of loop iterations.

in single-path symbolic execution, the values of a symbolic variable re.ect only thedatadependencies on the symbolicinputs control dependencies, includingloopdependencies, areignored.


The most obvious approach to mimicking humans would be a replay attack.

a bot could record a human play of the game and then simply replay the recording.


That means, when the neighbourhood is copied to anyplace of the image, the secret sum changes as follow.


Inferable Relationships (IRs) may include the following: (i) Equivalence relationship between two concepts.


Therefore, we first identify the important domain-independent relationships among concepts, categorize them and propose propagation policies based on these categories of relationships.

we allow propagation of authorizations based on the semantic relationships among concepts to prevent illegal inferences.


2 The key observation of the proof is that U1 n D2 = Ø from the typing rule for the sequential composition implies: ''' '' ''' '' m1 I(Ei ) m2 .

m1 I(Ei ) m2 , i = 1, 2 variables that appear in expressions that may be declassi.ed in c2 (namely, expressions from Ei ''' ), are never updated in c1.


To relate the behavior of our implementation to the theory of the framework, the semantics of calling a method not mentioned in the policy is considered to be the same as if the body of that method was recursively unfolded into the client code.

the labels of values returned by internal function calls are determined solely by the rules for arithmetic operations (as described in Section 7.1.1).


This way, only the credit issuer and the trusted merchant devices can write valid balances on the user s device.1 The harder problem is that of preventing the user from rewinding or replaying his account balance.

even if the balances are signed with an unforgeable signature, the user can still easily copy old signed balances and reuse these copies with different merchants.


DOFS stores enterprise sensitive files on a protected server and prevents bits of the files from physically leaving the server.

once a sensitive file is checked into DOFS server, its digital content can never be directly taken out.


In the simulation, they use an administrative model that is far more powerful than ARBAC97 or any other administrative model considered in the literature.

they assume the existence of administrative permissions each of which can simulate the effect of an ATAM command.


We observe that in most cases the attacks we developed were quite sensitive to minor tweaks.

although simple versions of the attack were quite easy to construct, maximizing their e.ectiveness required a lot more e.ort.


These are multiplied modulo N to form the multisignature a.

a = H(M) dl+d2 mod N. The partial signature al is considered valid if and only if a~ 1 mod N = H(M).


Characterizing the Behavior of a Program Using Multiple-Length N-grams Carla Marceau Odyssey Research Associates 1 Ithaca, NY 14850 carla @ oracorp.com ABSTRACT Some recent advances in intrusion detection are based on detecting anomalies in program behavior, as characterized by the sequence of kernel calls the program makes.

traces of kernel calls are collected during a training period.


All pixels must be in Oused(b) which represents all pixels of all used display areas.

for each pixel there exists an application that sets the pixels color, which ful.lls Req.


We start with the assumption that the attacker was able to penetrate the .rewall to place an executable on the end host (e.g., overwriting an existing application), evade the anti-virus software (e.g., by performing an xor with a bitmask), and execute the software on the end host (e.g., by the user running the executable).

we achieved this through a client-side exploit, altered the calc.exe executable, Table 1: Time of events of the example to obtain memory contents and recon.gure the network.


While our experiments focused on mass-mailing worms, the technique was general enough to apply to any class of malware behaviors.

we note that the variants in our test set exhibited behaviors above and beyond those traditionally characteristic of a mass-mailing worm.


This observation has been used to build forwarding mechanisms that use the notion of community to make messages .nd their way from source to destination.

this paper describes how to make use of the social nature of contacts to get a network stronger against the node capture attack.


We can also observe that the posterior probability that the original degree value di is far away from the observed value d i tends to be zero.

it is very unlikely that a node s degree has a signi.cant change after perturbation.


There exists a polynomial P such that |c * |= P (., N).

the size of c * is independent of t and |C|.


If a private key is not secret, then there is a potential rogue phone problem.

someone could place an authentic private key into a rogue phone.


They identi.ed that when tapping a touch panel, the exact coordinates of a tap were depending on the used .ngers.

di.erent .ngers could generate slightly di.erent coordinates.


INTRODUCTION In today s main stream operating systems applications are typically executed with the security context of the user.

applications have the same access rights as the user has on the system.


The third case is for a later execution of the PUF to produce x0 as a result.

there must exist some j such that the contents of Reg would be the sequence x0,R1,R2,R3,...,Rj = x0 Recall that we assumed (m = 1) |Cj| = |Rj | = |Rj ' | = |x0| = m = .- log2 .. Then the probability that any Rj = x0 would be 1/2m , which gives us 11 11 P (Rj = x0)= == == .


And a user obtains privileges through tasks.

only when the user is assigned to a task can she use the privileges associated with that task.


An important task of our system is to identify the actions of the code under analysis.

we are interested in observing cases in which the potential malware sample accesses tainted data.


Keeping in mind the diverse requirements on OPE, this article investigates randomized construction schemes of orderpreserving functions that improve on one-wayness-related properties of the ideal object .

when considering the functions produced by a speci.c scheme and an entry c .R of the ciphertext range, there is a distribution specifying the probability that entries from the plaintext domain D are mapped to c. For the ideal ob ject , this relates to the hypergeometric distribution [3], featuring a dominant peak at the most likely plaintext (m.l.p.


First is the propagation of sampling error as hosts repeatedly add together their hits and scans counters.

even though a given host, h, has a value scans = s, it is not necessarily the case that sdistinct scans were performed to compute h s hits value.


We present a framework for extracting topological and structural information from dense .lament networks stored in scalar volume data sets.

we describe a novel method for extracting the network structure that is robust in the presence of noise.


In order to make full use of temporal masking effect, the watermark is only embedded into attack-sensitive audio blocks in our algorithm, which have a high energy value.

the weak energy watermark is masked by the high energy audio samples in these audio blocks.


U to a reputation category (which can be thought of a number of stars ) such that the worst and best reputation categories are 0 and c' = 1 respectively, and where the user advances to the next category after having accumulated c = 1 additional ratings.


In addition, since the means to go from the input to the output is data-oblivious with respect to the I/Os (simulated using the address keys), the server who is watching the inputs and outputs cannot correlate any set of values.

independent of the set of I/Os, any input item, x, at the beginning of the sort can be mapped to any output item, y, at the end.


Active: We require a revocation mechanism that encourages sel.sh nodes to commit suicide for the good of the network.

nodes should be rewarded for sacri.cing a short-term loss in utility in favor of longer-term gains.


V endork: T 2Vi,k + T 2Vj,k = 1 (10) Equation (10) constrains that for any pair of dependent tasks i and j, T 2Vi,k and T 2Vj,k can never be 1 at the same time.

the constraint prohibits dependent tasks from being scheduled on cores from the same vendor and hence on the same core.


We further stretch several new and practical attacks, and then provide the solutions.

we have not seen similar solutions to authentication and authorization in the literature.


For instance, if the abstract state graph is deterministic, then there is an equivalence between the application s code and its abstract state graph.

the model is not an overapproximation of the application behavior but is an exact abstraction.


Although motivated by ICS, our proposed framework is generic, and can be used in other areas, such as health information networks, military and government information management.

access control for cloud-based information and computing services across security domains is a great challenge; our proposed framework can be used in a uni.ed form of attributed-based policies to combine RBAC with traditionally used mandatory access control, including non-hierarchical caveats, and other security polices; the framework also helps to deal with a great number of security objects, including both information and cloud services.


We argue that protection should be achieved through careful monitoring of activity at the DBMS layer.

we identify four dimensions of tasks and actions executed by cyber-insiders during data exfiltration missions; these are: identification of data sources, data retrieval from the DBMS, lateral movement and exfiltration proper, i.e., transferring data outside the organization.


Under the con.guration x, not all links may be feasible.

the data-rate of link l under x, denoted by c(x)={c1(x),···,cL(x)}, is given as follows.


This problem is illustrated in our own measurement data from sensors deployed in three diverse address blocks (two /16s, one /8) sharing the same upstream provider.

the sensors are address-diverse but topologically similar.


To understand memory cost, we focus on signature memory requirements.

experiments report memory space for route announcements, signatures and bit vectors.


The exposure of any other piece of information, such as session-speci.c values, should be of no use for the attacker to impersonate Alice in other sessions.

a basic security requirement is that the exposure of ephemeral session-speci.c secrets should have no bearing on the security of other sessions.


This raises complexity in designing and analyzing a user obligation system.

it makes it essential to have deadlines.


Instead, we .nd the most straightforward approach to be exactly that used by TPMs.

the PUF ROK device would require a certi.cate created by the manufacturer, storing a persistent private key generated by the manufacturer.


in the case of a = 100 , when every node sends a message with probability 0.21 after every random period, the probability of the event messages being discovered by an attacker is close to 1/n.


XXEA allows an attacker to read arbitrary .les within the context of the used web server.

it is possible to read con.guration and SSL keystore .les.


This decoding is stored as additional FastDecode (see Table 2) information and is attached to the instruction, so that it can be used to generate appropriate bytecodes later.

fastDecode information includes whether it is signed or unsigned, a bit mask, a bit shift and a summand.


A new group of MA attacks, called Branch Prediction Analysis (BPA), on the other hand, exploit instruction path of a cipher [2, 1, 4, 3].

an adversary can reveal the execution .ow of a cipher using BPA, and if this execution .ow is key dependent as in the case of RSA and ECC, then he can compromise the system.


In order to solve this problem, we leverage the asymmetry between the simulator and the cheating committer.

note that the simulator knows how to equivocate even at the start of the decommitment phase (conditioned on the event that it previously extracted a valid trapdoor from the receiver), while the cheating sender can only equivocate after the receiver reveals the trapdoor.


Instead of embedding one bit into an audio frame, multiple bits with different time delays can be embedded into each audio sub-frame.


In particular, the conformance relation under LGI is enforced by its very construction.

the very de.nition of a law N as subordinate to M,prevents N from violating the restriction imposed by M on its subordinates.


The .rst condition says that there is an algorithm that checks whether a given bit-string t * , that has been submitted to H1 by B, corresponds to the challenge y.

if the tester answers yes (1), then t * matches with the value of t as computed by the decryption oracle and additionally satis.es the sanity check; and if it answers no (0), then t * does not satisfy the sanity check.


This strategy will improve the performance experienced by mobile users of Tor when accessing the Internet not only for standard web-browsing but also for a wider range of services.

the successful use of streaming services, such as Voice-over-IP (VoIP), by a rapidly growing community of mobile Tor users, may depend on some such strategy, since the current design of Tor is likely to lead to a level of interruption to this type of service that will be considered unacceptable by users.


Finally, we show that reputation systems that are lively (in addition to being local and non-discriminatory), are more severely restricted.

if a reputation function is lively (i.e.


Unlike messages, locks do not induce failure dependencies.

if a transaction acquires a lock after it was released by a committed transaction, it does not become failure dependent on retroactive abort of the latter transaction.


However, our instrumentation approach also allows us to load additional, arbitrary Dalvik classes into an existing process.

we are able to write instrumentation and attack code in Java.


But a compromised machine might still try to read con.dential data from a remote host and then leak the data.

we assume that a run-time access control mechanism is deployed so that read requests from untrusted machines for con.dentialdatawouldbe rejected.akeystorewould not send keys to untrusted machines, so a compromised machine is not able to obtain con.dential databycorrupting codeexecution.


Rather than the conventional way of using tree map visualization for displaying the hierarchical pattern of IP addresses, we use tree map here to visually represent the hierarchy of the attacks types.

the tree map categorizes attacks according to their types such that every category displays IP addresses that have launched the corresponding type of attack in smaller squares.


2.3 The Role of Heuristics Safety properties of HRU security models in general are undecidable.

there is no algorithm that, given some arbitrary HRU model, will always terminate and tell us whether a given state is safe, rendering it dif.cult to devise algorithms for automated safety analysis tools.


More formally, we have the following de.nition [6]. '

if any change to will only be observed by and roles r r r ' more senior than any change to made by rr r. will not have unexpected side e.ects due to inheritance else-Definition 1.


To achieve its goal (e.g., introducing errors in the aggregate), the .rst thing that the aggregator would attempt to try is to modify individual data coming from participants whose data it is responsible to aggregate.

since a participant generates a tag for each of its data item using the Tag algorithm, we require unforgeability of Tag .it should be computationally impossible for the aggregator to forge a non-trivial tag of a victim participant.


In this section we discuss these di.erent approaches and compare them to our own framework.

we discuss in how far previous approaches adhere to the protection mechanism design principles.


Ef.ciency and Scalability Now,we proceedtoevaluatingthe operationef.ciencyof XACCESS.

we intend to capture the in.uence of twofactors: the scale of the underlying social network, and the volume of historical activity data.