Ej, ei can not be strictly less than ej.

one of the following two conditions must hold.


Exploiting this principle in the proposed framework implies retrieving the authorizations/prohibitions by querying the SAKB ontology.

for example, to verify whether a user u is authorized to specify access control policies for the read privilege on object o, it is necessary to verify if the instance AdminRead(u,o) is in the ontology, i.e., to perform an instance checking.


Second, merged instructions should combine bits belonging to the same word only.

the task is to move and merge as many instructions as possible while satisfying both conditions.


(For notational simplicity, we will not explicitly annotate an event with its corresponding principal.)

the principal associated with an event that violates some policy will be the entity that we want to punish; for an event that satis.es the formal de.nition of a violation below, we will refer to the associated principal as the violator.


Second, the resource manipulations in a candidate .ngerprint may be associated with multiple, possibly unrelated resource instances.

candidate .ngerprints must be re.ned using precision constraints.


These kinds of details in the timekeeping architecture of a system can be viewed as noise.

3.3.2 The Basic Steps here are the basic steps we use for .nding timers: 1.


In a network of size N with the expected degree d of each node, the average number of packets invoked by a newly-added node per each node is nearly (d - 1)2/2(N - 1).

as node density d grows, the total number of packets transmitted from adult nodes to a newly-added node increases.


Basic,Digest, NTLM) information for the domain.

this is done regardless of whatpagecaused thebrowser to initiate thisrequest.the webbrowsercanbecomeaconfuseddeputy[16],and thistypeof attackisknownasCross-SiteRequestForgery(CSRF).CSRFdoes not rely on XMLHttpRequest to work, and can be performed in a varietyof ways,e.g.


The active segment magnitudes extracted on the wrist watch and mobile phone are used as basis for determining if devices were actually shaken together.

one of these devices sends it s active segment magnitude over the secure channel to its counterpart device for further processing.


We further assume that the adversary does not use the query content to infer the client s location.

the adversary can only observe the location .eld in each client query.


When we apply threshold operator, the above equation can be written as P = t [A1 AND (A2 OR A3)]     where 1 = t = N For AtDRM, the dummy attribute .. is acknowledged as a mandatory attribute in making the access decision.

the access policy can be expressed as P = .. AND t [A1 AND (A2 OR A3)] We made an assumption that the user attributes are fetched from an Active Directory (or its equivalent) and the hierarchal access tree semantics are preserved during retrieval from the Active Directory.


The templates were authored by developers prior to our CSAS engine implementation.

we believe that these examples represent unbiased samples of existing code written in templating languages.


Implementation Non-Existence A proof that a particular implementation does not exist is typically harder to produce than a constructive existence proof.

in our work so far, when discussing a lack of an implementation, we often resort to informal arguments for justi.cation.


With the same number of sample runs, we observed that the mean execution time only slowed down to 2.473 seconds (less than 1 second) with an average of 84.24 calls.

we believe that our implementation is practical and efficient, because this short slowdown in execution time is almost unnoticeable and acceptable for a human user.


This proof is a LaTeX .le that includes the individual and batch veri.cation equations, with an enumeration of the various steps used to convert the former into the latter.

while Theorem 3.1 already argues that this proof is valid, this provides a means for independently verifying the security of any given batching equation.


The aim of dimensionality reduction is to preserve as much of the signi.cant structure of the highdimensional data as possible in the low-dimensional map.

mDS allows an analyst to visualize how far observations are from each other for di.erent kinds of similarity measures, which in turn can deliver insights into Figure 2: Visualization of geographical cliques of attackers.


But the statistical tests show these differences are not signi.cant.

h3 and H4 are not supported in our experiments.


Or, the temporal context day d can be noti.ed one day before: notifContext(day(d), day(d - 1)).

activation and violation contexts can be associated with noti.cation contexts in order to specify when obligation activation and violation are pre-noti.ed.


For example, if companies A and B are in con.ict, interaction of company C with A would result in information written to an access class requiring permission to both A and C s data.

when C interacts with B the data of A would not be leaked.


However, it maybecome clear that malicious activityis transpiring when looking at a sequence of views.

we introduce the notion of aggregating past views into a pro.le: De.nition 5 We de.ne P as the set of all possible pro.les.


3.1 Packet Sequences and their Features In general, packet sequences have four major features: unique packet lengths, packet length frequency, packet ordering, and interpacket timing.

a packet sequence P can be written as: P = (t1, 1), (t2, 2), ..., (tn, n) In the above, ti is the difference in time observed between packets i and i - 1 (interpacket timing), with t1 = 0; i is the byte length of packet i.


From our literature review, we did not find any SEND implementation for Windows families.

we decided to implement SEND for Windows.


Furthermore, this paper showed by experiments conducted on face and fingerprint biometrics that if two-factor biometric system is configured to yield a zero EER, an imposter with a stolen transformation key needs no more than two attempts on average to be falsely accepted by the biometric system.

we argued that setting a two-factor biometric authentication system to achieve zero EER introduces a serious lapse in security in the case of stolen keys where the False Acceptance Rate (FAR) reaches unacceptable levels.


By de.nition, the degradation ratio for B (i.e., b(S,D)(B)) is the sum of normalized occurrences of the links in B.

degradation ratio can be accurately modeled by the cumulative distribution function (CDF) of the Zipf-Mandelbrot distribution since the normalized link occurrence follows this distribution.


Using the .ow of tags as opaque predicates for obfuscation enjoys severaladvantages.

first, the .ow of tags is inherently a part ofthedata-.owof aprogram.thevaluesofthetagsare .owsensitiveinstead ofbeing constant valuesthroughtheprogram execution asinprevious approaches[6,23,20].


4.1 Open Linguistic Considerations Prounceable password generators must be able to generate nonsense words that humans would nonetheless .nd appealing; however, the properties that make such word-like strings appealing also represent opportunities for an adversary to narrow down and possibly rank-order the space of possible passwords.

we are concerned with the linguistic factors that a.ect the security of pronounceable passwords.


Remote access over the Internet is restricted depending on the control bit of the broadcast signal.

proximity check can be used to distinguish between local and remote devices.


This way, integration problems are detected early.

integration problems are easier resolved as they do not have time to grow.


[n] -{i1,...,it}), the item p(i)that A' presents to Ais uniformly distributed over the items not yet seen by A.

a'(u)is independent of u s particular item i .


However, in sensor networks using deployment, it is not feasible to determine the placement of nodes in advance because they are placed almost randomly.

key information should be pre-distributed to each node so that it can share a key with any neighboring node.


We can observe that the system s memory is only changed when a task is running.

we divide the system s memory into two parts.


Later, we used this DTW matrix as input feature space for standard SVM.

for prediction, each test example must be mapped using the same representation as we have used for the training data set.


gain advantage during the authentication in phase 2.


The relatively low sampling rate allows one to use an inexpensive DSO.

the whole attack takes several minutes and requires 1000 USDs worth of equipment.


In this case the algorithm veri.es that the .rst object is in input stream, whereas the second is an internal one.

in step 2.d.i, the algorithm calls Sec Read(Position,Rick).


Correctness: As according to the policy pro.le B1 is the only fragment bundle, the availability of the key e can be calculated as aj .

due to the minimum key- Sj.B1 availability boundary condition policy it holds that: aj = A Sj.B1  -wj 2-W .2= ij.K .wj = W ij .K the weight of all items in the knapsack does not exceed the knapsacks capacity.


In fact, seven reported that someone else had used their phone in the past four weeks (88% of 8).

these participants were concerned about regulating access to their devices, rather than locking others out completely.


We will prove in the next subsection that k=1 k=1 this construction ensures that the probability for a child node to be selected on the path is proportional to its count value reported in the aggregation phase.

a child with a larger count will be attested with a higher probability1 .


In this case, we may specify that the grantor must request the delegatee consent in order to activate the dynamic context.

context obligatee approval * will activate a pre-obligation for grantor S to request the consent of the delegatee S ' to delegate obligation D as follows: Obligation(S ' , S, req consent, D, immediate, Cv).


Moreover, for each query, at most one temporary key will be established between a device and the target device.

a query requires O(1) temporary space on each intermediate device and at most O(n) on the target device.


Moreover, fully pipelined architecture with a central controller simplifies the control of data flow.

for various applications, an image compression system can be rapidly built based on the proposed JPEG core architecture.


In this rule, all table lookups in Bob s policy are replaced with view predicates with the username bob as the .rst parameter.

when another principal, say Alice, accesses the picnic table, view.picnic will be invoked, but the .rst clause in the body of the rule will fail if bob does nothave read-access toAlice s employee tableinformation.


In which case, the token is valid when it consists of both values.

an adversary in possession of a single value cannot replay the token.


Nevertheless, the societal aspect is comprised of privacy techniques based on laws and regulations that help the owner to protect her privacy and con.ne the holder to certain rules that de.ne how to use or disseminate the personal information of the owner.

the .rst level of classi.cation of technological privacy techniques for LTE-based PSN branches out into two classes, .rst responders and holder.


Compared to the customized threshold, the static threshold scheme must compromise one false alarm rate for another.

the customized per-process scheme performs best among the three.


The same data set can be activated by different role mining algorithms.

we can do the comparison experiments on different algorithms.


In this case, P has a record in R2, but not in R1.

if a matching record r2 in R2 has to be the corresponding any instantiation.


At run-time, these data can be further classi.ed into stack, heap, and global at both the user and kernel level.

we denote Duser = {Dstack , Dheap , user user Dglobal = {Dstack kernel , Dglobal }, respectively.


For example, the operating system may update a .eld representing a performance counter quite frequently, but its value is not signi.cant to the correct operation of the OS.

to be con.dent that a signature based on a particular .eld will be robust against evasion attacks, we must ensure that the .eld cannot be arbitrarily modi.ed.


The query is then forwarded to the processor that executes in the same level as the query.

the query processor at level l can view only those input tuples whose levels are dominated by l and produce output streams at level l. during query processing overt information .ow can only occur from levels dominated by level l to level l. In the proposed architecture, level l receives tuples from dominated levels and stores them at its own level.


We think that the performance degrade on ARM is greater than on x86 due to the QEMU s emulation overhead.

we conclude that PIPs do not degrade performance signi.cantly.


Moreover, botnet operators may knowingly reserve static IP addresses for control channels, meaningthey neversend mail orbecomeblacklisted(Tab.4).

theseIPsfall outsidethescope of rulelearning(a segment we anticipated successfully mining).


To protect Alice s identity, this message must be sent privately to the rj encrypted using rj s public key.


After watching part of the video, the driver starts the engine and accelerates the car.

m edia is no longer allowed to present the video.


It is this paper's contention that due to the nature of asymmetric key-based authentication schemes at IPF-6 or above, they provide significantly better protection of credentials than secret sharing schemes.

this author believes that the IPF Scale provides better clarity with respect to authentication technology than the NIST LoA framework.


The problem becomes worse if the unauthorized node is a malicious user.

a mechanism is necessary that prevents an outsider from being part of the network.


The impact of mobile device use on password authentication and password selection is a relatively new area of research.

there is a lot of room for further investigations.


Note that Microsoft Outlook is not fully configured on the Application Servers.

users cannot read their e-mail on our application servers using Outlook.


Since physical properties depend on environmental conditions and measurements always contain noise, PUF responses of the same device are highly correlated, but not fully identical.

syndrome coding schemes such as Code-Offset Syndrome Coding [1], Index-Based Syndrome Coding (IBS) [2] or Differential Sequence Coding (DSC) [3] enable error correction for PUFs to increase the reliability of the output key.


This makes them particularly well-suited to evaluation by simulation.

the techniques we describe in this section are simulation-based.


Jif is designed for enforcing different IF policies in a program, which is more than we need.

we did not build our prototype over it, and instead, implemented our own lightweight tool for taint analysis.


As a design alternative (listed as Baton alternative in Ta-Each delegation token, including a signed hash of the dele ble 1), it is possible to avoid embedding a certi.cate chain at gation token prior to itself in the chain, allows cryptographic all by retaining all previous versions of AndroidManifest.xml veri.cation of the entire certi.cate chain.

this prevents an and the META-INF directory in future versions of the APK.11 adversary from removing, adding, or rearranging delegation signing a new APK will bind the current Androidtoken elements in the chain.


We OP m ()and service cost Cm ttt assume that all services running on the Cloud are trusted.

the value of ()is obtained by using: Rmt() SRd ()| d OPm ) ¦ ( 1 PRd ^.


However, for the scope of this paper we limited the feature set to the CDR records representing details from SMS and voice call transactions, used by most wireless carriers for billing.

for each user, we consider a set of features containing data from the CDR records corresponding to the SMS and voice transactions within each observation time interval.


First, in those nations that maintain a two-stage election tally process, where preliminary or uno.cial vote tallies are followed by more a more careful thorough canvass (often known as the o.cial or certi.ed results), the claim will be that any intrusion into networked tallies and transmissions of voted ballots can be corrected at the o.cial count.

use of networked communications should not be o. limits for transmitting preliminary tallies and voted ballots.


We assume that the collusion strategy is independent of the index i in the sequence.

we can describe it for any index i, and we will drop indexing for sake of clarity in the sequel.


The greater the information gain, the most discriminating that feature is.

they sort features based on the information gain and keep all features above a threshold limit in their discriminating set.


The program counter label summarizes the information depen- dencies of the decision to arrive at the corresponding program point.

a declassify operation using the authority of a set of prin- cipals P introduces the integrity constraint:/(p._q) ___ Ip where "rp is the label {?:pl,...


By default, TrustDroid denies all untrusted applications network communication to local addresses on the phone and the Policy Manager instructs the FW Manager to enforce this isolation also for newly installed untrusted applications (step 11 in Figure 6).

any local network communication between trusted apps is isolated from untrusted apps.


In case verifier is stolen by breaking into smart card database, the attacker does not have sufficient information to calculate the user s identity IDi and password Pi.

the proposed protocol is secure against leak of verifier attack.


When traceroute does not reach a destination we assume the presence of the destination immediately past the last hop found.

the 3For IP to ASN mapping, we use the public IP-to-ASN mapping database by Cymru (https://www.team-cymru.org/ Services/ip-to-asn.html).


In our running example, line 14 checks if the variable discount has a value.

every fserver generated from an input that fails to set discount will always include the constraint ¬required(discount).


This adds 2.34 ms. Computing all these numbers, the minimum period of activity for the CH is 85.8 ms.

the minimum duty cycle in 16 minutes is much lower than 1%.


Then a topic is chosen from a multinomial distribution over topics speci.c to the author, and the word is generated from the selected topic.

a multi-author document inherits the mixture of probability distributions associated with each author, allowing the mixture weights for di.erent topics to be determined by the document authors.


),s)in case Server tries to see whether Alice and Bob are at the same place or not.

the Server cannot deduce anything from these messages.


All of these stages deal with small amounts of data that are loaded into memory in a single step.

they are hashed in their entirety before they are given control.


Martina Zitterbart University of Karlsruhe 76128 Karlsruhe, Germany +49 721 608-6400 zit@tm.uka.de or simple feasibility reasons, tiny sensor hardware is not tamperproof and therefore an attacker willing to eavesdrop or even modify essential data might compromise a loyal node for his purposes or add a malicious node to the network.

data transportation starting from a sensor node towards a data sink has to be protected against such threats.


the computing complexity for PD is not high.


Interestingly, .NET s HTTP library outperforms WinInet for larger documents; the margin is large enough to mask ServiceOS s overhead.

native Windows applications that used WinInet may actually encounter faster content fetch with ServiceOS.


If the relation is bi-directional, i.e., either data item can influence the other, we denote the relationship as x < I ; Y We assume that any data item can be updated by using its previous value.


4.1 PKI Vulnerabilities Trust based on a chain of single keys is compromised if any key in the chain is compromised.

the use of traditional PKI for trusting a key within an update system, whether that key is for signing .les or for transport layer security, is problematic.


Axiom (3) states that if a user u can activate a role r, then all the permissions that can be acquired through r can be acquired by u.

for the case where user u and permission p are assigned to r, the axioms imply that u can acquire p. Similarly, axiom (4) states that if there is a user session in which a user u has activated a role r then u acquires all the permissions that can be acquired through role r. We note that axioms (1) and (2) indicate that permission acquisition and role activation semantics is governed by explicit user-role and role permission assignments.


A few thousands students configured his/her private Gmail account to retrieve messages from the student mail server and Gmail periodically accessed the POP server.

the number of POP accesses to the mail server was almost stable, and it represented the number of authentication request to the LDAP authentication server.


Then we use this simulator to simulate the communication transcripts.

the deniable property can be proved via the simulation process of the simulator.


While an attacker can craft such a stack on normal MCU, IBMAC prevents this as the malicious code isn t able to freely modify the return stack.

it is not possible to maliciously manipulate the control .ow with return-oriented programming, even tough arbitrarycodecanbe runonthedevice.


In essence, it is inappropriate to manually assign the set of semi-id features due to the following reasons: (1) if a smaller set is empirically designated, then users privacy might be inferred as long as the correlations among features could be found; and (2) if a larger set is pre-de.ned, then the data privacy might be over protected, and consequently deteriorates the performance of the subsequent data analysis.

the algorithm capable to identify an appropriate set of semi-id features, especially in the context of big data, is urgently needed which could then be integrated with most of existing privacy preserving algorithms such as kanonymity [19], [17], l-diversity [10] and t-closeness [6].


Finally, we have that p should not be less than t, since otherwise c will be incompatible with RH .


Secondly, we note that a considerable number of accounts followed by the Twitter users is actually represented by news feeds, i.e., BBC, CNN, etc., celebrities, notable academics and 4 http://www.swansea.gov.uk/index.cfm?articleid=44946 other popular figures.

in a sense the Twitter social network reflects the interests of a user, rather than his or her friendships.


However, substituting the label of an edge is just to change the way in which two stages are related.

it should have less cost than edge insertion and deletion.


Taking the Rate procedure into account, the asymptotic execution time of the MaxAvail algorithm amounts to O(m* n ), where n constitutes the number of stores and m the 2 *2m maximum number of bundles de.ned in the policy pro.le.

it does not depend exponentially on the num 2For the sake of simplicity, we only address vulnerability in the explanation.


This means components may be exported by the platform, even if the developer is not expecting it.

any time the platform implicitly makes a component exported, this can create a security risk.


The longest trace we found had a length of 4 (Table 8), while any successful attack that attempts to brute-force the current ASLR implementation will inevitably create a trace of size close to 1024 (the number of di.erent randomization o.sets used in our implementation) over a relatively small number of attacked devices.

crash address trace size is an excellent indicator that can be used to detect ASLR derandomization attempts.


Section 4 is devoted to describing Patrol in detail.

we show our basic setup, the security mechanisms we have implemented, and the token communication.


The attacker can launch a DoS (Denial of Service) attack consisting of a single flow of packets to trigger these last-matching rules, i.e., overwhelm the firewall with hoax packet processing.

with a low-rate flow of these packets, the cost of processing and filtering becomes so high that legitimate users will eventually be denied service.


In obfuscated databases with group privacy, computational cost of access depends on the amount of information retrieved.

group privacy can be thought of as a step towards a formal cryptographic model for economics of privacy.


However, the difference would soon disappear since calculation performance of computers increases day by day.

in our proposal, amodal completion is applied to three dimensional objects in order to increase the calculation cost for a computer more than the cost for two dimensional objects.


Likewise, the ways in which strength increased between the EM and PPM conditions did not observably di.er.

we merged the two experimental conditions and performed a Wilcoxon Signed Ranks test to compare the characteristics listed in Table 2, between participants previous and changed passwords.


bob s friendship with Charlie would be counted as part of the 68 friendships where both people lock.


Note that many steps in this process can be performed offline.

offline preprocessing will significantly reduce the average time required for online generation of challenges.


OPERATING SYSTEM DIVERSIFICATION One of the main goals of an operating system is to provide a variety of services that programs use in a shared manner [24].

the operating system and its system call interface are an abstraction between user applications and the services provided by hardware of a computer.


However, sensor nodes embed low-cost crystal oscillators which drift from the reference time.

sleep Tsleep and wake Twake periods are not equally measured by all the sensor nodes.


Whilst one service provider might solely support CardSpace, another might only support Liberty.

to make these systems available to the largest possible group of users, e.ective interoperability between systems is needed.


In the preamble .elds, HT-LTF1 to HT-LTFN represents the known sequence sent via each individual antenna for receivers to estimate their CSI.

these .elds do not leak CSI either, because CSIsec sends an unknown sequence U in those .elds instead of the original known sequence K. the only remaining .elds that might leak CSI to eavesdroppers are Figure 17 Packet structure in 802.11n/ac.


The analysis also applies to the aggregate operation performed by the requester.

to authenticate a delegation chain of length n (i.e.


[5] use binary strings to represent both customer policy con.gurations and document policies, but they allocate one bit per policy on the assumption that there will be a limited number of di.erent subscription types.

1If k = m log n then the card can explicitly store the m items.


If the maximum similarity score continues to converge towards the value 1 after each consecutive step in the set of performed interactions, then the visualization produced by the active user is becoming similar to a visualization used to identify or detect a suspected attack by an expert user.

as illustrated in Figure 1, NAVSEC is guiding an active user to a visualization completed by an expert user.


We can conclude that |D| = 1,000 is su.cient to discover the power-law distribution in the top100 rank because it displays the same power-law distribution in the range as that observed with smaller size for D; i.e., |D| <1,000.

with a relatively small number of measurements one can learn the power-law distribution of the few but frequently observed high-rank links.


The rationales behind using the timing correlation are the following: 1) fast worms strive to propagate to and infect as many other hosts as possible in the shortest possible time; 2) fast worms are usually small in size.

the volume of worm infecting tra.c is small.


This allows users to perform variety of tasks on these devices.

smartphones usually accrue sensitive information over time and often gain access to wireless services and organizational intranets.


Moreover,there must be a point i in this sequence such that .l < i,rl = j and ri = j.


This problem is particularly di.cult with languages such as PHP that are weakly typed and not formally speci.ed [25].

we complement a form of static analysis taint analysis with the use of data mining to predict the existence of false positives.


For these forms, the user has already assisted iTrustPage, albeit unknowingly, to validate this page.

iTrustPage does not ask the user to perform an additional Google search.


Generally the components that simultaneously match tens of thousands signatures at the speed of multiple gigabits per second are required.

effective pattern matching algorithms and architectures are very important.


The absolute addresses of these entrypoint functionsarestoredintheinternaldatabaseoftheloader,and they point to the image loaded at the original base address, causing false-positives when they are dispatched.

when image loading is hooked, we parse through the loader databasewhichisaccessiblefromPEB(ProcessEnvironment Block), and convert these entrypoint addresses as soon as theyareregistered.


While these negative results show serious limitations on the possibility of general-purpose obfuscation, they focus on speci.c (often cryptographic or contrived) functionalities.

they do not rule out that obfuscation may be possible for many programs of interest.


Survey Results A primary goal in both of our experiments was to maximize ecological validity during the password creation and login phases by making these tasks required steps to complete larger subterfuge tasks.

up until this point, we did not reveal the true purpose of the experiment.


points are added one-by-one, constrained by the requirement that no two points are close to each other, until it is impossible to add more points or suf.cient number of points have been added.

if the original template consists of s points, and the total number of cha.


We distribute compromised nodes over an inner square area with 200m each side (from 150m to 350m of each side of the 500 × 500m 2 target area).

compromised nodes are strategically-placed in between the base station and the source node.


They require symmetric routing on local and non-local wires, which is very hard to achieve, as shown in [14].

rO PUF are currently the best choice for general FPGA PUF designs.


The output of the Extract function may be random, but we may not have guarantees about the uniformity of this randomness over its many bits.

we need to use a scheme that provides security even in the presence of this potentially weak key.


Second, a non-LUT implementation of the Extended Euclidean algorithm occupies a non-trivial number of FPGA resources.

in a resource-limited FPGA such as ours, rather than unnecessarily use flip-flops, LUTs, gates and various routing resources, a better choice is to put the table in the FPGA block RAMs, in a parallel approach.


Furthermore, if RoM is equipped with software to analyze recent logged requests, it could identify apotentially misbehaving User by identifying any IDU identi.ers that are associated with an abnormal number of requests.

while both of these types of denial-of-service are possible, it is our observation that these attacks are not contingent on the design of our architecture, and a number of mitigation techniques are possible.


ON THE CONSISTENCY OF RESILIENCY AND SEPARATION OF DUTY POLICIES As we have discussed in the introduction, resiliency policies are a natural complement to traditional safety policies in access control.

a question arises regarding the consistency of resiliency policies with other policies.


Some aggregation functions are found inherently insecure, such as MIN/MAX, because the change to a single sensor reading can cause noticeable changes to the .nal result [9].

we also consider a content-based attestation approach to validate an outlier.


Inspection of the inference rules for atomic policies (Table 2) shows that only one of them can hold at a time.


That report proposed a core consisting of 280 lecture hours with the assumption that a normal three credit hour semester long (15 week) course has 40 lecture hours.

280 lecture hours is equivalent to seven three-credit-hour courses; in other words, 21 credit hours.


The proof of the theorem relies on the observation that to maintain the truth value of each predicate for each tuple of entities, we need O(n a) bits, because § each predicate has arity at most a.

each authorization state can be encoded with O(pn a) bits, which is polynomial in the size of the input, given the assumption that a is a constant.


We make no computational assumptions and therefore model Eve as being computationally unbounded.

this requirement implies that all the entropy in R comes from w. one of the most important requirements of such a protocol is that the output length of R must be as long as possible given the entropy of w. The di.erence between the entropy of w and the length of R is called the entropy loss.


As discussed above, mesh routers can be distinguished by the parameters they hold and by the operations they perform.

we imposed the burden of the master key generation on them, which decreased the number of nodes present in that phase.


The DFA is represented compactly without wasting any memory slots (states shown with dots in Figure 6 point to other states not shown in our example).

this representation lends itself to a high-performance implementation.


According to [1], calculating UAS in line 1 is not within polynomial time.

exhaustive-Search is not within polynomial time either.


Instructions have the form [instr id,args].Initialization instructions set an initial value and also point to the instructions to be executed when the counter reaches 0.

decrement and test instructions are combined into a single instruction that decrements a counter and compares it to 0, executing the previously supplied instructions if so.


The standard way to de.ne a t-conorm is to use a t-norm: S(x,y)=1-T((1-x),(1-y)) [16, 11], and the S is referred to as the T s dual t-conorm.

the three dual t-conorms are: Sg (x, y) = max(x, y) (Gödel t-conorm)  Sp(x, y)= x + y - x · y (Product t-conorm)  Sl(x, y) = min(1,x + y) (Lukasiewicz t-conorm)  The criteria for choosing an appropriate t-conorm are exactly the same as for t-norms.


As a correctness test for Ktmp the VMKR contains the encryption of a bit-string with prefix 0xDEADBEEF under the correct media key Km.

whenever decryption of the ciphertext using the temporary key Ktmp results in a cleartext with prefix 0xDEADBEEF, Ktmp is equal to the correct media key Km with high probability.


Since all messages are eventually unicast, it is easy to see that all the topology sensitive schemes (TI, TD and TC) will be equivalent in terms of revocation messages generated and message visibility outside the destination set.

we will have n-1 unicast messages being generated on the last hop whenever any member leaves the group.


As a result, there is usually no way to even communicate a security failure to the subject performing the read or write1 .

security failures have to be mapped into other failures that can occur on reads/writes, such as an attempt to read a .le before opening it.


Of course, this method inherently contains an error margin (in this case, ±500), but for a larger domain size, this error margin seems quite reasonable.

we argue that our attack approach is equally applicable to attributes with larger domain size.


The evaluation shows our approach effectively protects a smart phone against a new kind of DoS attack that sends excessive I/O requests to drain limited system resources in virtualization environment.

it guarantees good performance and availability in most any circumstances.


BUILDING CIRCUITS THAT HAVE UNI-FORM TOPOLOGICAL STRUCTURE When a circuit is scrambled, the operation in each gate is hidden; however, the topological structure of the circuit is not.

the client could infer some information about the server s function by looking at the scrambled circuit if the server constructs the circuit in a naive way.


If that condition is not true, then it means that ß is an old version of ORAM block b, so ß is free, and it can be safely overwritten.

u can therewith check if a block is free in constant time.


next state for a number of states is a function of both the present state and Code-Word.

the value of the obtained Code-Word plays a key part in determining the transition relation in the functional mode.


For each of these groups, it uses a unique DEK.

a recipient cannot read data for a group it does not belong to.


Otherwise, the robustness condition ensures that, if the adversary can in.uence a declassi.cation, then it can also directly access the declassi.ed information [Zdancewic and Myers, 2001].

depending on the lattice, a program with some declassi.cation (hence not necessarily CNI) may still be compiled, with an implementation that provides the same security guarantees as for the source program against the restricted class of adversaries that make it safe [see also Chong and Myers, 2006].


Mathematically, this is written as max,(1 -P1(6)) subject to Po(~) _< ak.

we compute the likelihood ratio and decide H1 is true if fk(xlH1) _ > ~ (5) where T is the decision threshold.


Indeed, from our simulation results, we observed that the mean of the false negative of the Base protocol over all the simulations is about 43.6%, while the mean of the Adaptive protocol is about 42.9%.

the Adaptive protocol not only has better performance respect to the Base one, but it has also a lower percentage of false negative.


Also, to perform security-critical tasks (such as spawning new processes, modifying .les, or contacting network services), a program must invoke at least one system call.

we believe that it is reasonable to monitor the progress of a running program by inspecting the system calls that it invokes.


Moreover, negative policies are also useful to preclude undesired resource accesses or information disclosures due to wrongly speci.ed positive authorization policies, if the Deny takes precedence over Permit approach is used to solve con.icts among authorization policies.

the decision type of xfACL, decisionT, includes both Deny and Permit.


Unfortunately, thread termination in Java is an inher- ently unsafe operation, because the terminated thread immediately releases all monitors.

objects may be left in an in- consistent state.


make sense in general context (as shown in Table 4), those in .-1 may not have a clear meaning.

care should be taken in constructing cardinality constraints based on them.


If attackers can absorb this much delay they will be able to perpetrate undetected short range attacks.

the number of clock cycles required to calculate the response must clearly be very small.


Although often overlooked, the security of virtually all cryptographic protocols stands or falls by the strength of the random number generator (RNG).

a secure RNG is one of the core building blocks of cryptographic designs.


PROBLEM STATEMENT AND MOTIVA-TION The problem of access control to data has been investigated by the data management community.

several techniques and models have been proposed to improve data security and ensure con.dentiality [12][8][10][2].


For simplicity, we assume here that timestamps are simply natural numbers with 0 representing that the event has not occurred, and with other values increasing monotonically with time (e.g., the current index in the action sequence).

the case in which the object add precedes the user join can be identi.ed simply by comparing the associated timestamp values.


The number of WSN nodes can range up to thousands of nodes.


Finally, PjScan learns from malicious PDFs only.

it has no way to select discriminant features, in order to achieve high accuracy.


As it is a proprietary implementation, RSSI values from di.erent vendors represent in general di.erent physical circumstances.

we were interested in establishing a more objective base for our measurement campaigns.


Obviously, when the receiver acquires the watermarked image, the authentication information being embedded can be extracted for comparison.

the receiver will be able to verify the integrity of the watermarked image as well as identify any possible area which has been tampered.


Instead of direct function calls or accesses to DOM objects, developers would be forced to layer such interaction on top of asynchronous postMessage-based protocols, which carries extra marshalling costs and may be hard to design correctly, as illustrated by recent .aws found in Facebook Connect and Google Friend Connect [19].

a developer may be discouraged from converting some content on an HTTPS site into HTTPi to bene.t from its cacheability properties.


If eavesdroppers cannot successfully record a wireless signal, no amount of computing power will allow them to extract useful information.

physical layer security has been attracting much attention in wireless networks.


For Sweb, the inputs of a program are just the initial web state, and any web state resulted from program execution is part of the outputs.

a program s satis.es the noninterference property if evaluating s under two web states with equivalent lowcon.dentiality parts results in web states that also have equivalent low-con.dentiality parts.In otherwords,low users cannot distinguish the two executions.


As new network transactions occur, our tools will display them on a moving timeline.

analysts can dynamically zoom through data spanning months or years in just seconds.


If this intuitive approach is deployed, it has to trap all writes to memory pages containing kernel hooks, even those not targeting at kernel hooks.

it will introduce signi.cant performance overhead, particularly from frequent unnecessary page faults that are caused by write-accesses to irrelevant data.


To ensure that the existing non-CR receivers can properly receive signals, the authentication tag must be transparent to them.

we present two schemes, one conducting tagging in QPSK modulation, the other in the error-correcting coding.


It assigns a .rst-order model (Dw, = w, Rw, Fw) to each world w. Let the individual elements of Rw be denoted as ri,w, and the elements of Fw as fj,w .

s enables a potentially di.erent .rst-order interpretation at each world.


However, for redundancy removal at policy set level, both redundancies among children nodes and rule (leaf node) redundancies, which may exist across multiple policies or policy sets, should be discovered.

we keep the original segments of each child node and leverage those segments to generate the authorization space segments of PS.


This is the only assurance a correspondent node gets from BU.

the protocol is able to provide good protection against the session hijacking attack provided the number of bits in II, (128-n), is large enough.


Let t1 be the number of auctions that occur until (and including) X s .rst win, t2 the number that occur after that until and including X s second win, and so on.

.ki=1 ti = t.Since X does not win until auction number t1, X is defeated in the previous auctions.


The free XOR technique [KS08] allows to compute garbled linear gates, i.e., XOR and XNOR gates, without communication (no garbled table is needed) and only negligible computation.

the dominating factor for the complexity of a circuit is the number of non-linear gates.


Note that, some of these actions occur individually within normal operations of DBMS.

our aim is to provide a thorough characterization and classification of suspicious actions, which will be used later on in the detection phase (described in Section 3) to accurately separate true exfiltration activity from false positives.


Setting an appropriate value for n. A higher value of n should theoretically make the system more secure, but also puts more strain on the user s memory.

we suggest a maximum of n = 4, as there is evidence that the number four is considered to be a limit on the capacity of human memory [14].


Essentially, this violation makes applying existing work in document similarity for identifying infection vectors impractical, because core elements are discarded.

we introduce our own similarity measures.


After .ltering out other system calls except the system call we intend to trace, and selecting the system calls exercised by the actual fuzzer process, we store the trace output in normal text .le as strace and SystemTap.

in some cases, the .ltered storage overhead can be higher than the original one.


In this view, security experts and systems designers have already made the security choices for end-users.

by making end-user security invisible, users can pursue their primary tasks without the annoying disruption of dealing with purportedly secondary security tasks.


In other words, Cover Locations indirectly take into consideration the user query patterns (as recommended in the work of [30]), since it generates locations close to the real locations, at times the user visited those locations.

we can conclude that the Cover Locations provide an acceptable level of privacy even when the adversary has access to the user location history.


However, the processing time was longer than we had expected; it took about 5 seconds to hash them using the processor on Veri.er.

we included a hash accelerator in SnapMon to shorten the processing time to a reasonable level; and it improved to be about 1.3ms to hash one snapshot.


Since e and ni are small, pi can be approximated to pi =1-(1 -e)ni nie.

the set of trials of mi within dt can be uni.ed to constitute a single Bernoulli process with success probability nie.


In a public key scheme, anyone can encrypt data without any secret information.

in a public key PCE system, we can allow anyone to encrypt documents for the patient s .le, and upload rights do not imply the ability to read other .les in the same category.


However, the resulting privacy guarantees can be simpli.ed as a P3P promise that is o.ered for the users of the services.

p3P is used to publish an enterprise privacy policy in order to collect PII from the customers while E-P3P is used for internally enforcing the enterprise policy to control accesses to the collected PII.


Another important standard access control language is XACML, an XML encoded and attribute-based policy language, which supports a .exible speci.cation of access control policies through the use of permit and deny rules within the same access control policy, and the combination of (possibly different) decisions from different rules by policy combining algorithms.

xACML has also been selected by several ongoing industrial and academic projects, e.g.


i=1 i=1 This shows that the more a node collects the receipts, the required memory storage gets larger.

considering that di is much lower than pi in most cases, the overall storage requirement mainly depends on the number of the collected receipts.


A wrong id will not guarantee that a fabricated sensor can set up a pairwise key with uncompromised sensors.

by restricting the distribution of the number of rows of a secret matrix A to .,we can prevent the node fabrication attack.


Finally, she will use the category names to generate the appropriate decryption keys and will thus decrypt the desired .les.

the key aspects we have to cover when describing such a scheme are (1) how the directory entries are generated, and (2) how they are decrypted.


First, in Scheme 2, the members that join in or before session i are expected to compute all their shares on qi(x), ..., qm(x).

we can reuse the masking polynomials as discussed earlier.


We specify our transcript form aiming to categorize several kinds of data it contains, which will structure the subsequent security discussion.

a Faerieplay transcript T consists of entries of the form (Time, Operation, Data).


The monitoring at MSb continues till [(t-.)+(N*.)].

vb is constructed at MSb as follows: ( Vb = ., Fb1 , Fb2 , Fb3 , ... , Fbl , ..., FbN ) (3) The correlation coe.cient, denoted by ra,b(Va,Vb)or simply r(Va,Vb), between the target vectors, Va and Vb, is obtained by the following equation [10]: 1 PN r(Va,Vb)= [Va(l) -V.a][Vb(l) -V.b](4) Nsasb l=1 .of the monitored features of the vector Va, respectively.


If the number of bits representing a group element of G is approximately log(N)=6., then our secret key has length 3n log(N) = 162. bits, and the variables in our update matrices can be represented with 2(n - 1) log(N) = 96. bits.

the amount of leakage al  1 lowed per update/signature is roughly a 162 fraction of the 1 secret key length, a 96 fraction of the update randomness, and a 1 fraction of the total length of the secret key and 258 update randomness.


We analyzed the resources o.ered by mobile devices to identify contexts and properties relevant to the users and their behaviors in pervasive environments.

the following authentication-relevant contexts were identi.ed [21]: Operational context: describes the goals, tasks and activities of the user;  Interpersonal context: describes the social aspects of the user, such as the relationships and communication channels between the user and his community;  Spatial context: considers attributes regarding the use s location;  Environmental context: captures the situations surrounding the user, such as services, people and information accessed by the user.


For example, in Section 5 we are able to solve FullObserve for small IEEE bus topologies due to their small size.

by establishing that our PMU placement problems are NPC, we claim that there exist bus topologies for which these problems are di.cult to solve (i.e., no known polynomial-time algorithm exists to solve those cases).


This rigid structure means that it isn t always possible to neatly match a given software state with a single hardware mode.

we instead decided to treat the security evaluator s set of modes M as also forming a lattice, in this case ordered by mode inclusion, with any at the top and none at the bottom.


This is good news compared to Table 5, all of the percentages are markedly lower.

it will be harder to guess the password which was strengthened which means that a GBF attack will take signi.cantly longer.


Since we assume b > 0, the expression in (8) is quadratic in c with 22 2 leadingmonomial2b2 c (note that c¯= (1-c)2 = 1-2c+c ).

(8)is minimized if its derivate with respect to c is 0: .


In a monotonic system, once an obligatory action becomes enabled, it remains so in later states.

weak accountability in this context is equivalent to requiring that each obligatory action is enabled at the end of its time window.


Within a transaction, some of its operations may be independent of each other.

not all operations of an affected transaction are affected in case of an attack.


One difference is that it does not need to take the new (possibly smaller) universe as a parameter as no new false positives are introduced when elements are removed.

we can infer the new universe simply from correctly removing any elements that are no longer false positives as a consequence of the removal of elements.


The boundaries concerning a di.erent type of attack are highly expandable and in most cases not yet technically exhausted.

we consider the following attack scenarios as hard to match with the remaining categories.


Emulators based on binary translation avoid some classes of transparency failures, since they can completely replace instructions, but they are complex enough that making them completely transparent would be impractical.

our goal is to successfully emulate a malware sample, even if an emulator suffers from transparency failures that anti-emulation techniques would normally exploit.


Indeed, with network connections measured in gigabits per second but with latencies measured in milliseconds, the number of rounds of communication is likely to be the bottleneck, not bandwidth.

because of this ordersof-magnitude di.erence between bandwidth and latency, we assume 1/c M = N, for some .xed constant c = 2, but that Alice s memory is smaller than N. Equivalently, we assume that c = logM N is a constant.


Fourth, the OS can only manage the page tables during a context switch, when a process suspends or resumes execution.

a multithreaded application cannot isolate the memory accesses among its threads when the process is the smallest principal.


It is important that not only are faculty and staff trained in the proper behaviors necessary to secure information, but that Information Technology students are taught these as well so that they will be able to participate in the development of information security programs upon graduation.

it is necessary to determine if university faculty and staff are engaging in proper information security practices, and if not, how we can make recommendations to correct any flaws in our practices, best train our users, and include these best practices in the pedagogy of our information technology courses as well as in employee training.


An internal stream can be de.ned in terms of (the portion of) the graph by which it results.

given an internal stream S and the corresponding graph G, the protection object like representation of S can be de.ned in terms of the boxes contained into G. More precisely, given a graph G, not containing an Union box, de.ned over a set S in of input streams we can de.ne the stream S resulting from graph G, as the Cartesian product of streams in S in, where all attributes speci.ed in the Map boxes of the graph G are projected, and all predicates speci.ed in the Filter, Join and Resample boxes are applied.


the outdegree of a vertex in the backward state graph is bounded by |g|2dt.


Computed hash values are used aspointers into thetransitiontable implemented in the BlockRam of the FPGA.

the actual look up in the memory consumes one clock cycle.


The basic idea is that aggregation enables indirect assignments (e.g., subject type-permission assignments) in models that use them.

for a subject type-permission assignment, subject types may be aggregated by one or more aggregate statements, and they may be assigned to a permission aggregate which is constructed by one or more aggregate statements over permissions.


Real-world virtualized infrastructures consist of tens of thousands low-level components and similarly many edges, an initial complexity that could easily overwhelm the solver back-ends.

we support the solver back-ends in traversing these graphs e.ciently by either abstracting from low-level nodes not impacting the analysis or introducing fast lanes into the graph: Definition 6 (Optimization: Graph Refinement).


Open source based sensor applications have been developed as well.

applications share more and more common code as they use similar development environments.


The results show that we obtain less than 0.50% switching probabilities of the HT gate in all the benchmark circuits, which is considered very low and di.cult to observe by the switching power-based detection.

our results indicate that the attacker can leverage the rare but non-zero switching activities to activate the HT during the operation of the wireless system, since the one-gate HT is di.cult to detect before the actual activation of the malicious circuitry.


We note that as discussed in Section 3, our integrity control system is supplementary to the conventional access control mechanism.

the purpose of ACP being discussed here is to prevent improper accesses, not unauthorized accesses.


In V2V communication, PIDs are generated with initial PIDs by TPD, biological information and timestamps.

any V2V message could be used by KMC to trace its biological author with privacy preserving.


In case of an anomaly, perturbations in this dependence structure are .agged as anomalies.

the level of temporal dependence can serve as an important metric for modeling anomaly scores.


However, di.erent countries can have di.erent legal constraints in respect to bank secrecy, data security, privacy, cryptography, etc.

an access control system that regulates the access to data from different countries has to account for the law situation of the source and destination country of the data access.


If at some point, any byte in the address space of X is tainted, it means that the sensitive data has leaked into X, which should not happen.

the program must be malicious and is probably a keylogger.


In this case, the Web server did not halt and sent the  Figure 7: Detection of Sequence of attacks error message appropriately.

the administrator knows that the attack did not succeed.


This indicates that noise reduction increases the probability of a spam source being identi.ed as well.

both false positives and false negatives are reduced after noise reduction.


Then when the next patient contributes her secured rating to the system and the scores get updated and published, it is likely trivial to .nd out what value, and for which physician and condition, the patient submitted a rating.

the aggregate scores must be protected as well, with only the recommendation data (such as a sorted list of best-ranked physicians) made available.


Thus, in some way, an access control authorization represents a relationship p between u and o, meaning that u can exercise p on o.

we decide to encode an access control authorization for privilege p as an instance of an OWL object property, named p, de.ned between the authorized person and the authorized resource.


In addition, the management of certi.cates or keys and their revocation lists from multiple external suppliers is technically complex.

many organizations may not want their end-users to have to deal with these issues.


At the same time, the e.ectiveness (i.e., number of pre-empted .les) of our algorithm decreases with tighter distance thresholds as can be seen in Table 1.

there is no single correct value for the checkpoint time and the distance threshold.


What software can verify for now is the syntactic validity of sentences structures.

we will develop the method of Word Substitution to overcome this problem.


Any attempt to fake the execution of SENTER by directly extending them or modifying them after SEXIT can be detected.

the end user can verify the integrity of the MLE as mapped by the guest OS using PCR-18 of the target VM s TPM.


Every piece of information here is actually meant to be disclosed by Android and most of such data has been extensively used by legitimate Android apps: for example, hundreds of data usage monitors are already out there [5], relying on the usage statistics to keep track of a user s mobile data consumption.

.xing these information leaks must be done carefully to avoid undermining the basic functions of these existing apps and to strike a balance between system utility and data protection.


It is ine.cient for a group with many users when the keys are re-distributed frequently, e.g., multiple users need to be revoked asynchronously in one time slot, or multiple users need to be revoked in di.erent time slots, or the revocation needs to persist for multiple time slots.

it may not be suitable for a large group with frequent revocation, highly dynamic group, or long term revocation (key exposure).


Given M as de.ned in (7), deg(cj) gradually decreases as stated by Equation (8).

the minimum number of iterations iis given by 2m-n-1 -i(m-k) :0 2m-n-1 =i>,* (17) m-k '' For polynomials over GF(2) a,b' with deg(a) <n and deg(b') <n, c0 = a' *b' can be partially reduced to c=c0 mod M,deg(c) <nas follows: c0 can be split up into c0,h and c0,l with deg(c0,h) <n-1 and deg(c0,l) m. the minimum number of reduction steps iis n-1 n-1 -i(m-k) :0 =i>, * (18) m-k 7.


Our experiments indicate that this increase is small and does not lead to drastically larger state machines (see Section 7).

this approach is e.ective for creating deterministic hardware monitors.


It generates a signature s * = ots.Sig(sk * , (E1 * ,  {C.i }i.L,vk*=0, {C.l+i }i.L,vk*=1,CJ).

ii It outputs the challenge ciphertext as E * = (E1 * , {C.i }i.L,vk * =0, {C.l+i }i.L,vk * =1, C, s * , vk * J ii If (g, A, B, C, Z) .Dbdh and we let s = c, then we have s).i Y s = e(g, g)abc , E ' = C.i =(g = T 's and E ' = C.l+i = (g s).l+i = T 's the ciphertext is a valid random i ii l+i.


Furthermore, these paths in Gb contain at most one occurrence of each cycle in Gb, because transitions that go around a cycle in Gb a second time would not add more irrevocable roles or constraints to the corresponding forward states, hence the corresponding fragment of the path in Gf would be a cycle, contradicting the assumption that the path in Gf is simple.

the number of states in Gf is bounded by the number of paths in Gb that go around each cycle at most once.


Finally, communication with a backup C&C server might use a slightly different format that cannot be detected by our C&C signatures.

9% and 8% mark the lower bound of samples that revealed valuable endpoint information.


This could be achieved, for example, through a secure credential establishment protocol [9, 10, 21].

these keys and permutations are derived and known to each member of the group but not to the server.


Other examples are when a patient chooses to volunteer in aresearchprojectorsharespartsoftherecord withan insurance company to adjudicate insurance claims.

it is neither possible nor e.cient that the patient looks after sharing with each single individual.


FLOW OF EVENTS The author has created a web-based messaging system, similar to an email system, that is used to provide authenticated login and to communicate with each team [6].

announcements can be made to each team depending on the part of the scenario that is happening.


Furthermore they both rely on an of.cial vetting process as a measure against malicious applications.


She is free to select any p from a password space P that is permitted by S. When the number of characters in the password is restricted (and it is so in most systems), the space P is finite.

each user has a username (picked from set M) and a password indicated by mapping U : .


Obviously, this resulting value can not pass the validity check as shown in algorithm Decrypt.

reencrypted ciphertext CT ' j can not be decrypted by Uj with overwhelming probability.


In a federation the authentication of a user is not necessarily performed within the service provider s domain, but can be performed in the user s local domain.

the service provider has to rely on authentication results received from a federation partner to enforce access control.


Notice that the client side update and the server side update go through the same computations, except that the server also updates the labels of nodes along the veri.cation path.

the time cost of the client side update and the server side update is roughly the same.


After max k ÿ attempts, an attacker will be in the s state and » max continues to remain in that state after subsequent incorrect attempts.

to launch any meaningful attack, the attacker will have to do so from the s state.


Since Update algorithms of both in [5] and proposed scheme consist of computing a abß mod n, the computational cost of both Update algorithms are in proportion to the size of a and ß.

update algorithm of the proposed scheme becomes |e|/|e' |times faster than that of [5] since a and ß will also be in ' proportion to the size of e and e, respectively.


Note that the diagnosis engine can easily determine the correspondence of instructions in di.erent crashes by reversing the memory remapping (using the information about how the re-mapping is performed).

the diagnosis engine can determine the non-Case-IV crashes through a majority voting, and choose any one of them for the subsequent analysis.


yi ' .i, i.e., extrema indices Both the transformation functions and reduction factors are known to the receiver-side.

based on the received transformed value yi ' , its corresponding true value yi can be recovered.


The malware programs might simply decide to stay dormant in this case, which undermines the malware detection capability.

we also mark the cluster requesting any bypassing behavior as malicious when disallowing the behavior.


Our key evolution approach is designed in a way that only devices d that are in the same context as the target device d1 for the majority of the time during a key evolution cycle will succeed in the key evolution step.

since correct peers are signi.cantly more often in the same context than wrong peers, the value .


In addition, the pro.ling is conducted along side the covert channel communication, its resolution is therefore constrained by the polling frequency of the target channel.

the results should not be viewed as a characterization of the scheduling properties for the underlying scheduler, but just a concrete example to illustrate the impact of environment factors to the channel bit rate.


For the obtained Radon image, we compute Eigen values.

given a matrix A, a scalar A is called an eigen value of A if there exists a nonzero vector x such that, Ax = Ax for a square matrix A of size nxn, the eigen value equation can be expressed as- Ax - AIx =0 Here, I is the identity matrix of size nxn.


By contrast, a disabled role cannot be activated by any user.

constraints on enabling of roles specify when roles can actually be activated by users.


It is also noticed that the structure of the network can influence the propagation of the dual-stack worm.

it is necessary to consider the worm defenses in the future Internet construction.


At the same time, we can pre-compute a ' = e(u, a), b ' = e(g, a) and c ' = e(v, a), and publish them as part of the designated con.rmer s public key.

in the con.rm and deny protocol, C and V only compute some exponentiations.


Second, being either the spam target or the relay, the remote SMTP servers are usually very reliable; and the implementation and listening port of these servers strictly follow the SMTP protocol semantics.

the packet symmetry rule always holds, and SMTP packets can be easily identi.ed based on the port number of TCP header.


If the only event is a send to j then Sj will not be in.uenced since the only sub-state received as a result of a message will contain the initial time stamp equal to the time stamp of the local sub-state s0 and therefore will be removed by the algorithm (lines 23-24).


These chunks are copied exactly, so any moved header chunks will retain their old timestamps.

chunks moved due to garbage collection may appear to be newer than they actually are.


We are still guaranteed that the map will have O(logn) levels, but we reduce the communication complexity of a map operation by a factor of O(log n).

in terms of communication complexity, reading from the map is constant in O(B), and updating/writing is in O(B·logn).


for r!number LAP we have 2Pr number of PD values.


That is, the compliance checker must return zero or more sets of local evidence that minimally satisfy p so that the local entity knows which local evidence can be sent to the remote entity to gain access to the resource protected by p. We say that some set E of evidence minimally satis.es a policy p if no proper subset of E also satis.es p. A compliance checker capable of recognizing all possible subsets of the local evidence that minimally satisfy a given policy is required to ensure that a trust negotiation protocol will establish trust whenever possible and can also a.ord its user a number of strategic advantages.

our focus in this paper is to e.ciently solve the following speci.c instance of the more general policy compliance checking problem: The Type-3 Compliance Checker Problem.


To see that it is bounded by some function of |NR n PR|, note that the set of nonpositive roles in the state is the same in every state in Gred except the initial state, because the reduced transition relation never adds non-positive roles to the state, and revocation has no preconditions, and hence invisible transitions that revoke non-positive roles occur only in composite transitions leaving the initial state.

the set of non-positive roles is the same in every state in GNR except the initial state, so the number of nodes in GNR is bounded by some function of the number of positive roles in NR.


With this assumption, we increased the number of shares needed in the reconstruction process by increasing the number of shares that the mesh routers hold.

resiliency of the system is increased without increasing the number of required neighboring nodes.


We count the number of frontier packets in each di- Figure 1: Attacker Accuracy vs. Bandwidth Ratio tackers, respectively.

while the BuFLO and CS-BuFLO trade-o.s might vary depending on the attacker, the Glove trade-o.


4.4 Exploit Firmware As the utilization of the co-processors includes the definition of entry-points, interrupt service routines and further con.gurations, we tend to choose a standardized format for our exploit.

the adversary-.rmware is organized in the executable and linkable format (ELF -format [5]), which is the common standard for executables in UNIXlike OS and also the binary-format for co-processor utilization frameworks like remoteproc [11].


Each path upwards from PE1 includes the role PL1, which is controlled by PS01.

the conditional constraint is satis.ed and PE1 is in the administrative scope of PS01.


She uses a rental car for company business trips.

she is interested in the new pay-for-use (PFU) program that is offered by her insurance company, Giant Inc.


While adhering to the principles and the methods ofprovable security, veri.ed security takes the view that cryptographic proofs should be treated in a manner similar to high-integrity software, so that con.dence in the designof acryptographicsystemis nolowerthancon.dence in the software systems that use it.

veri.ed security mandates that security proofs are built and validated using state-of-the-art technology in programming languages and veri.cation.


In the mouse data collection, a continuous mouse movement is discretized to a set of mouse coordinates, which are sampled at a certain rate.

the measured resolution of mouse movements is dependent on the polling rate of a recorder.


Due to the unattended nature of a sensing node, it is possible that an attacker tamper with it in such a way so as to alter the data it is sensing.

our .rst application is secure data collection, or trusted sensing.


While deceptive mutation in.icts more computational overhead than random mutation, it is more detrimental to persistent attackers (refer to Section 6).

the IP mutation takes place according to the random strategy, unless we observe abnormal in.ation in the size of connected components in the network connectivity graph.


In We make our hypothesis that the reason why social promoters tend to have close friendships with criminal accounts is probably because most of them usually promote themselves or their business by actively following other accounts without considerations of those accounts quality.

promoters may become criminal supporters by unintentionally following criminal accounts.


A kernel function basically maps non linearly separable data to high dimensional space, where data is linearly separable.

it is very important to use an appropriate kernel for better classi.cation accuracy.


Except the initial node bus 1, all buses present different measured and estimated phase.

the Control Center has to search the correct Reserveddata and generate the DEK.


Once a system call is permitted, the resources on which the system call operates are not further restricted.

this approach should always be combined with other access control models.


Second, because multiple applications can execute concurrently, the TLR runtime must be multitasked.

each trustlet service thread is bound to the respective application process running in the OS-domain.


Some of the initially suggested OPF schemes rely on traditional encryption techniques to generate intermediate ciphertexts, assign them to buckets based on the order of their underlying plaintexts, and prepend bucket identi.ers to obtain resulting ciphertexts [4, 5, 6].

with the bucket identi.ers, ciphertexts can be compared, allowing e.cient range queries.


Moreover, if two packets arenotsent back-to-back, say the intervalbetween these two packets being largerthan .CAP ,then the IPD will be equal to the original interval if there is no cross traf.c[21].

althoughRAINBOW andSWIRLintroduce asmall delay to the packets, they disturb the distribution of IPDs less than .RTT .


The Google Play divided its applications into 34 categories.

at least 34 roles are set of initialization in our model and users can assign one or more roles to an application after the installation, besides, a role can be assigned to one or more applications after the definition.


NA and PK cannot convey the intention of users, so they are inadequate.


However, note that .R1 as well as R are random values with unknown discrete logarithms, which can not be computed using any values from signatures or public keys.

the values tT (a)P + R and dP are uniformly random and, consequently, e(tT (a)P + R, dP ) as well as C = H ' (e(tT (a)P +R, dP )) are also uniformly random.


Since q > 2 3 kn2 log n, for a constant k, q = O(n 3) and log q = O(log n).

protocol 1 sends O(n) bits and computes O(n) operations.


However, accessibility support usually o.ers interfaces to programmatically generate user inputs, such as keystrokes and mouse clicks, which essentially enables the interface to act as a human being.

it might be possible to bypass these defense mechanisms and abuse a user s permissions by generating synthesized user inputs.


As many Android apps designed to serve a dedicated web application, MyFBApp is designed to serve Facebook only.

if the web pages inside WebView only come from Facebook, the risk is not very high, given that the web site is reasonably trustworthy.


Here, it is possible that the dynamic code generation library is loaded at di.erent locations on each instance it is loaded.

cFIC maintains the signature as a [module:o.set ] pair to validate across load instances.


The system often uses a handle as an ID of an object, not as an address, so it would be problematic if handles are regarded as an address for our conversion, because then the system would not be able to recognize them.

when parsing through therelocationtabletolookforpre-generatedaddresses,ifan address points to the base address, we leave it unconverted as it is most likely used as a handle.


T. Because the way tracing is de.ned, all bu values will equal 0.

the probability that the relation = over T has a single equivalence class is equal 1 - negl, i.e.


This list is intended to contain what look like plausible passwords users might generate; it is not intended to be a list of highstrength passwords.

this honeyword generation scheme is qualitatively di.erent than the process of tweaking a password to generate anew password: it is OK for a honeyword tobe much weaker than the true password in an attempt to trick the adversary.


After 8 seconds, the script navigates the browser to a fake re-login page to phish the user s password.

in this involuntary navigation scenario, what the user perceives is exactly as if the login page voluntarily navigated to the re-login page.


When this happens, the permis sions of the variable are updated to the static permissions of the function that updates the variable.

iBAC model tracks during the whole execution the information about which function had in.uence in which variable.


For the application to utilize persistent objects stored in the database, they have to be returned within SQL responses .rst.

we collect all the observed SQL queries and responses, as well as the corresponding session variables.


However, since each object can implement its own version of a method, the same selector might refer to di.erent implementations.

the Objective-C runtime determines the appropriate method implementation based on the class of the receiver at runtime.


However, new governmental regulations (e.g., Sarbanes-Oxley [22]) assume data encryption for publicly-traded companies, health and government organizations.

for these companies and organizations, secure deletion via encryption is much cheaper because the encryption-related overheads are paid in any case.


Second, query sets restriction and data perturbation hurt usability.

we propose using lightweight detection approaches as an alternative or complement to prevention approaches.


On the other hand, this conclusion is challenged by Ozment, who showed that the pool of vulnerabilities in OpenBSD 2.2 is being depleted and vulnerability rediscovery is common.

he gives the opposite conclusion, i.e., vulnerability hunting by white hats is socially bene.cial [18].


Shared cryptographic .le systems (e.g., [32], [40]) share .les among a group of users.

these systems should complement the basic cryptographic services with more sophisticated key management techniques that e.ciently handle key sharing and key revocation.


tees of anonymous communication networks [6].

aN OA is a useful building block for analyzing anonymity, but it lacks the generality to model the scenarios in MATO R. we extend the AN OA framework in this section such that it is suitable for proving that the anonymity bounds of our MATOR monitors are secure.


The space needed for each state is polynomial to the input size which includes the initial user-attribute assignments, attributes scopes1 , query and administrative policies.

all problems are in NPSPACE and thus also in PSPACE as implied by Savitch s theorem [32].


We observe that this chain is usually no longer than three for most applications.

we look back for two interactions in our inference.


From this log, the TTP can check the usage status of each of the user s certi.cates, and produce validation certi.cates that attest to the usage status of the user s certi.cates at that time.

in a future transaction with another user (not requiring contact with the TTP), the user need only present a PRU containing the validation certi.cate plus any new incproofs, and does not anymore need to present any old incproofs that have been seen and validated by the TTP.


Obviously, the information hiding capacity is finite when selected one pair in original image.

numbers of pairs are increased in location map to improve the capacity of embedding information into the cover image.


The other receives a message on a and, if its second component is s, it forwards the .rst component on a channel b.

we may say that s serves as a capability (or password) for the forwarding.


The remote control over infected machines enables an attacker to abuse compromised systems for .nancial pro.t, for instance to distribute spam messages or steal password and credential information.

means for detection of malware communication are crucial to combat current threats on the Internet.


The error of the clock estimation is below 15 µs for Sk < 16 CL CL CL minutes.

by adding the error and the minimum accuracy, we conclude the minimum precision of cluster time is 25 µs for 2 <Sk CL < 16 minutes.


We evaluated the computation costs of this secure comparison by .xing m = 5 and varying values of n. Following from Figure 1(b), the running time of secure circuit comparison varies from 37.45 to 185.013 minutes when n is changed from 1000 to 5000 respectively.

we observed that the running time of secure circuit comparison grows almost linearly with n. Based on above results, as shown in Figure 1(c), the computation costs of O-PPBA protocol scales approximately linearly with n and m. For example, when m = 5, the computation time of O-PPBA increases from 39.032 to 194.934 minutes when n is varied from 1000 to 5000.


Since TrustZone is implemented in hardware, it averts software vulnerabilities as found in pure software security solutions.

it is possible to protect peripheral and memory.


These statistics show that there exist a large percentage of lowend smartphones produced by low cost manufacturers in developing countries and these devices domain the Android smartphone market.

the exponential growth of Android and the abundance of low-end smartphones attract hackers to develop new ways to distribute malware.


Interestingly, all these utilities read proc .les to inspect the kernel state.

.le access related syscalls: open(2), read(2), fstat(2), stat(2), lseek(2), readv(2), readdir(2), close(2) are of our particular interest.


However, it is dif.cult to achieve high-performance computation while keeping cost low by combining all the building blocks on a single chip, because the silicon fabrication technology for the NVRAM and that for high-performance computational logic are different.

today s trusted hardware is generally slow, which affects the throughput and latency of the whole system.


These requirements, however, might not be necessary for all services within the federation and might change if this service is dynamically replaced.

users are forced to authenticate by a prede.ned strong authentication method, even though weak authentication would be su.cient for the service they want to access.


If the records do not have a foreign key (FK) relation or a similar primary key (PK), they cannot be linked using a simple SQL join.

a more complex action is needed in order to match the congruent records.


Given the recursive nature of KOP s memory traversal, an incorrect object may cause more errors during the rest of the traversal.

itis critical to reduce identi.cation errors and prevent them from propagating.


Application developers are not supposed to provide their own lock screens for these devices.

it is hardly surprising that there are no programming interfaces that allow for the implementation and integration of such a feature.


Fur-thermore, instead of involving all the authorities to produce the pseudonym, one can use a threshold (blind) signature scheme [35].


Since the second condition holds, the designated winner bid Bg, yet the sale price is sp = Be > Bg.

if the fourth condition is violated without triggering detection, then the designated winner must have colluded, possibly tacitly, as this bidder is now obligated to pay more than its bid!


4.5 Implementation Aspects The aim of SecureLock is to deny the usage of the device without prior authentication.

secureLock is intended as a substitute for Android s screen lock.


The resource restrictions of these devices, thus, limits their ability to store large volumes of data or to perform complex and sophisticated computation, which implies that the amount of security that these devices can o.er is limited.

our work aims at providing an optimized security solution that increases the unpredictability / uncertainty associated with the communicated messages, increasing the system security.


We cannot estimate how many others chose not to participate for similar reasons.

it would at .rst seem that our sample is biased toward users who are unconcerned with privacy.


On the other hand, it is obvious that M-Gap-SQDH = Gap-SQDH since one can use the DDH oracle to answer DSQ oracle queries.


Our example uses a backend relational database management system.

the objects of protection are relations, tuples, attributes and views using modes of access operations such as SELECT, INSERT, DELETE and UPDATE.


For this reason we do not have anyspeci.c support for a not function.

our model cannot be categorised in either of the traditional de.nitions of open and closed policies.


Although the nonce is contained in the HTTP request, it is not replaced with the actual secret data since the name of the POST parameter does not match.

the attacker cannot utilize the search functionality to extract the secret password data from our password manager.


The devices themselves may not have any user interfaces.

zero-interaction pairing will greatly improve the usability of con.guring these devices.


The basic patterns address the modelling of parallel execution branches and the merging of these branches.

consider the following work.ow description given in Figure 1 consisting of four human tasks, where task t2 and task t3 are executed in parallel.


However, there is still a concern that given inauspicious traf.c which may actually be arti.cially crafted by an attacker the state construction may eventually consume more memory than we have available.

we also implemented a memory-bounded DFA state cache.


In practice, quantitative risk assessment is in many contexts missing the necessary reliability for automatic decision-making because of insu.cient input data quality.

we see the decision-support approach, as suggested in this paper, as more practical.


However, breaking a card is costly and will mostly be done for economical reasons.

employing techniques that protect from massive sharing might be the most appropriate action.


The EROS kernel does, in fact, use the same variable in both calls, and we know from the implementation that any attempt to decache the process must ultimately call either proc NeedRevalidate() or proc Unload().As long as neither of these functions is called, a cached process will remain cached.

so long as the value of param1 has not changed before the call to proc GetRegs32, we know that the process remains cached.


The construction of M shows that the complement of RCP( ) is in NPNP .


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

memories that agree on these expressions before starting c1 just as well agree on them before c2, and visa versa. ''


(1) Map each state variable to one user attribute whose scope corresponds to the domain of the variable.

s0 and s* map to two different attribute assignments.


Trust values are then used by peers to exclude untrustworthy peers (which send inauthentic .les) and to select peers from whom to download .les.

the number of inauthentic .les in the network decreases.


Unfortunately, hX (·) is not su.ciently universal to make it a good extractor, and therefore we cannot argue that S ' itself is random as long as ¯ I has entropy.

we need to apply an additional hash function h ' = [X ' · Y ]m which takes as input X1 (Y ) 1 Y .


2N+2 = .. + j · (8 log q(nB)) the .nal error after a multiplication and relinearization is at most ... +8N log q ·(nB)2N+2 = ... +(B ·n)O(N) , as claimed, for the setting of q =2n .


Although current STM systems incur high costs, hardware acceleration and language support may soon provide competitive overhead[42].

in the near future, much software may be written to use STM techniques.


A partial identity contains only a subset of all user attributes.

partial identities can be designed in way for data minimization and privacy protection on the application layer.


For instance, the HR system may not contain all users.

it is important to .ag imported users in the ERBAC repository.


The number of possible codes for Bi+1 is in the range of [n +1, 2(n +1)], according to Lemma 1.

the jammer can jam the transmission of Bi+1 by randomly selecting a code from these codes (rather than from Cp).


To provide access to XSEDE cyberinfrastructure, each end user must be mapped to a speci.c user account that is connected to an allocation.

the ideas provided by eduroam are valuable, but they must be extended.


As a result, the taint storage overhead on the stack is also limited to 256 KB.

we focus on the taint storage overhead on the heap, which dominates the memory overhead of taint tracking in Dalvik.


The assumption here is that n = 3k +1 where k is the maximum number of nodes which can be compromised in a given time frame.

this technique even handles compromised nodes which give byzantine output.


However, the biggest problem for this approach is it has to pick up a victim process from the guest-OS and replace its program execution context with the implanted one.

to the victim process, its semantics has been completely disrupted.


The rules about Sealed Envelopes (SE) use information from the care records and the workgroup memberships.

their type is: types SEPolicy = (Operation ×Spine ×S) m.unit A user is allowed to read an entry directly (i. e. without breaking a seal), if the entry is either not sealed or, else, he is a member of the respective workgroup.


Note that it is important that the attackers not be able to calculate the actual assignments for any other players but their own; if they could, that might help them incriminate an innocent player.

a feasible extension of our approach is that the code assignments are randomly permuted at each code position, that is, at each variation point in the movie, and in each movie itself.


For example, Amazon Web Services o.ers both the Simple Storage Service (S3) and the Elastic Compute Cloud (EC2).

we might develop a collocated PDP service, leveraging more complex data possession proofs in CBDG.


Now, Bob runs an FTP client (gftp standard implementation) and logs in to Alice s FTP server.

bob is able to list and read the contents of Alice s home folder; he transfers the usage-controlled .le AlicesFriends.txt to 1http://zvi.ipd.kit.edu/english/26_422.php   Figure 2: Mousepad fails to open the protected .le.


We assume d is measured from the end time of b1 s interval.

b2 s stipulated time interval in our approach will be [e +d,e+d+w].


In the ideal case, the minimum time to send a bit using L2 cache is the sender s write time (Tw) plus the receiver s read time (Tr).

the maximum bit rate would be 1/(Tw +Tr).


Since this number is unique for a sensor and no attacker can compromise more than .

rows of a key matrix A.the attacker cannot fabricate new sensors by installing new row elements to a fabricated sensor.


In these cases, we document the .rst published policy that we found.

while there is no guarantee that we .nd the only password policy in force at a university, there should be no bias in the policies indicated in Table 7.


All we need to to is to use a good authentication protoocol.

we would like a version of Strategy C based on an authentication mechanism that does not require server knowledge of the user password, so that the same password can also be used to encrypt the user data.


When Bob requires Alice to show her driver s license, Alice responds with policy P.Only after P is satis.ed by Bob will Alice tell Bob that she actually does not have a valid driver s license.

the policy Pactually speci.es under what circumstances Alice can tell others the fact she does not own a driver s license.


Each .ag contained (cryptographically) the service that it belonged to, the state of the service (active or not), and a timestamp signifying when the .ag was created.

when a .ag was submitted by a team, the .ag submission service had all the necessary information to determine the .ag s validity (.ags were valid for 5 minutes).


The receiver needs to keep state of the most recent value it received for each hash chain.

the receiver can easily verify the authenticity of new values by hashing them and comparing them against the most recent value of each hash chain.


Unlike the Tahoma system, where each VM is an application component that does not interact with the host system, we envision that our distributed applications may leverage some host system resources.

we cannot use the Tahoma approach where policies are de 1Freely available information, which is analogous to open sourcesoftware.


Particularly, the card must act securely in face of an untrusted or malicious terminal2 .

the anonymous credential system must protect the citizen s security andprivacy autonomously and cannot(easily)delegate computations to the terminal.


To this purpose, the algorithm makes use of the Sec Join operator (Sec Resample operator) over the requested stream.

in this case the authorized views are given by the Aurora expressions obtained by applying the Sec Join operator (Sec Resample operator) over Objs1 and Objs2,plus the views generated by applying the Join (or Resample operator) over each possible combination of Aurora expressions in Sec Objs1 and Sec Objs2.


Such a pairing for the network can never be done autonomously without any user interaction, because otherwise an attacker would also be able to legally add an arbitrary number of malicious nodes to the network.

the user or a special device, the so called Master Device (MD) representing the user, must establish the initial pairing.


i, in the transformed space rep resents a convex set.

the intersection of them is convex as Each of the halfspace conditions, H Then for any i .


The NOP sled achieves this by occupying buffer space with non-operational code that correctly identifies the beginning of the payload.

the likelihood of it directing program flow to the payload increases, albeit at the expense of providing a bigger signature for detection as the ratio of NOP sled to payload increases.


By specifying the style of the protected Web page with stylesrc,it is possible to restrict the access to undesirable CSS .les.

cSS-based animations for reading DOM nodes or a usage of the CSS content property will no longer work in this case as an attacking tool.


And in Liao-Wang s scheme, the number of use the hash function is 15 times except registration phase[8].

these schemes have more efficiency better than our scheme, however, these schemes are not safety.


This approach requires the modi.cation of the mobile operating system itself.

this interception method is only feasibly for open source operating systems such as Android.


Again, random selection process does not consider any available factors to get a correct authentication selection decision.

adaptive selection algorithm is a feasible option to satisfy these criteria.


The return gate subsequently restores the saved program states and returns to the original call site (line 8).

each inter-module call requires two system calls.


For example, it becomes a hard task to perform discrete Fourier transform (DFT) or discrete wavelet transform (DWT) on the whole image in the encrypted domain with the packing method.

the packing method do not satis.es the non-interactive property.


In other settings, as for example the server-side detection of web-based attacks, one is restricted to passively wait for attacks using network honeypots.

it is not possible to put together a representative set of server-side attacks in a timely manner and classi.cation methods should not be employed.


In addition, to establish the identity of genuine with high trust, the biometric matching need to produce a large number of mutual information between two biometrics to indicate that the two actual biometrics are from a same individual.

it is important to maintain a complete biometric information.


In such environments, multiple virtual instances run on the same physical machine concurrently.

the isolation in the system is not guaranteed by the physical infrastructure anymore.


Denning and Denning characterize explicit .ows [19] roughly as follows: a .ow of x is explicit if and only if the .ow depends abstractly on x (that is, it depends on the existence of x,but not on the value x).

for example, the violation of DFI in Example 3.2 does not depend on the value empty any other value causes the same violation.


The models thathavebeenpreviouslyshown mainlypresent the following limits: On one hand, it is so easy to assign semantic labels (eg Very Trustworthy, Trustworthy, Untrustworthy) ([1], [18]) as it is more complex to give a numerical evaluation.

most solutions that address the trust evaluation make one of the following assumptions: (i)The trust initialization is not a problem of the model, it is the responsibility of the actor of the system.


Because all vehicles participating in V-Charge are relaying and storing currently valid Bundle Revocation Lists while parking, these lists can be kept as Floating Content [14].

arriving vehicles immediately receive currently valid lists either from the PM or from other parked vehicles.


s. We note that in our case the gaussian nature of the attacker is solely assumed in order to make the formal analysis feasible, the proposed algorithms (Algorithm 1 and 2) do not rely on this assumption.

regrettably, the Maximum Likelihood decision is not applicable either in our case.


Open source based sensor applications have been developed as well.

applications are sharing more and more common codes as they are using thesimilardevelopment environment.


Hence, a change may be represented as: (si,oj ,ak) .c (si,oj ,ak' ) It can be readily inferred that .c is a three-place-relation over S × O × A.Furthermore, let M denote the class of all possible ACM versions.

.c can be thought of as a binary relation over M and '' M .c Mi.


In addition to the existing elements, it proposes the presence of an EvidenceType element, which enables carrying a set of Assertions or Assertion references.

the AP can validate the Assertions presented as Evidence and based on that issue an appropriate Assertion, in response to the AssertionRequest.


The security of the scheme depends on the properties of the algorithm and the quality and secrecy of the key.

cryptographic keys need to be created and managed carefully.


Decisions on how to handle ongoing trust negotiations during a policy change are business decisions that depend on factors such as the reasons for replacing the old policy, nature of the changes, importance that all ongoing instances comply with the new policy, and existence of temporary transition policies.

instead of providing a .xed change management process, we provide policy management operators that policy developers can use to de.ne their own change process suitable for  their needs.


Recently, both the utility and the complexity of the cyberspace has exploded in an unprecedented manner.

there is an imminent need for protecting these cyber infrastructures.


Fix some constants d and .. We will show that for all large enough m, any algorithm Q that takes as input X and a stream St ' and outputs a·a ' ±o( v m) with probability at least 1-O(m -2) can be used to compute a vector a such that ai = ai for all but an .

fraction of i .U with probability 1 - d. the existence of such an algorithm Q implies that X cannot be E-di.erentially private for any .xed E. Indeed, assume for the sake of contradiction that an algorithm with the given properties exists and X is E-di.erentially private.


This entity represents the parties that wish to conduct secure transactions.

a User can be a Subject wishing to securely access a LBS or a Target that requires to securely send her location information, or a LBS that receives connections from mobile users.