If password policy does not require a suf.ciently complex password, users are more vulnerable to their passwords being cracked.

if a password policy requires an overly complex password, users may have dif.culty remembering their passwords consistently and may therefore write their passwords down.


Moreover, NoForge needs to maintain server-side state in the form of valid (session id, token) pairs.

jCSRF does not maintain state, and is less prone to DoS attacks.


This reduces the implementation complexity of maintaining its own rights policies database for inside users.

dOFS s application execution model creates one problem: Sharing permissions of sensitive files are never checked when they are accessed by server application processes because these processes are considered local processes on the DOFS server.


Through binary data dependency analysis, we can easily determine that the address l must be the value of ebx+esi.

the general situations where T argetAddr(v) may be computed from the corrupted data require additional research.


All these services and providers can also be part of the mobile TSS.

a TSS implementation might become very large so a discussion about specifying a slim mobile TSS might be of interest.


Our simple and adaptive mitigators use the polylogarithmic bound log2 T , which appears to make a reasonable trade-off between performance and security.

as this section illustrates, even with this more relaxed bound, the distance between deferral bounds increases exponentially.


Observe that moving from easy to fair distortion, as wellasfrom fair to good distortion,substantiallyincreases protection against automatic recovery.

the extra security margin o.ered by insane distortion is rather limited.


Hence, one may prefer to suppress duplicated volunteers when the .rst volunteer broadcasts its intent.

this can also help adversaries because a malicious node can volunteer quickly to suppress others, and then never deliver the hotspot list to the o.ine authority.


Security experts believe that if a dynamic technique that meets the aforementioned requirements can be developed then it will be resilient to code obfuscation, self-encryption and polymorphic transformations of a stealthy malware because a malware .nally has to do the desired malicious activity while it is executing.

these transformations can easily defeat well-known static techniques.


Based on their most recent demographics report, released in June 2010, our sample closely resembles the larger Facebook population of users.

we underrepresent the 18-24 group, and overrepresent the 25-34 age group (Table 2).


As a result, we do not address this issue directly.

the capability expiry mechanism can approximate the e.ect (to within a capability-reissue period).


"X"   "30-40"   "765XX"  2.3 An Example Graph Transformation Step We show the general steps of the medical procedure only for one patient in Figure 1 for clarity.

in reality Figure 1 would be a subgraph of a much larger graph that describes provenance for n patients.


It grants at least moderate level security for the system.

it is worth noting that the security level implied by our approach is not quite as high as the one introduced by isolation based systems, e.g., [3].


A simple back-of-the-envelope calculation shows that for a one-bit SECTAG, an 8-way associative, 64K L2 cache, with 128 byte lines, requires (block size×width(SEC T AG)) or a 128-bit tag per cache line, if the tags are added to each line.

with our scheme, the number of additional bits per cache line is 2+log2(#sets)+log2(associativity)+log2(8/width (SEC T AG)), or 14.


The model was presented in a formal simple case study to demonstrate the application of the model.

the above-mentioned research works do apply context-awareness on traditional access control such as Rolebased Access Control (RBAC).


To obtain e(U0, SK1)nA, the last four elements have to be eliminated.

the values of the last two elements are unknown to the adversary, and cannot be constructed.


All three Insert conditions resulted in improved passwords having signi.cantly more estimated bits of security than the Control and Replace-2 conditions (t(831.87) = 13.50, p < .001).

the three Insert variations produced improved passwords of similar estimated security (F(2, 480) = 0.32, p = 0.727).


As long as they use their privileges for precisely the purpose for which they were granted1, they will not commit an insider attack.

it is easy to see that GTIP 2010 Dec. 7, 2010, Austin, Texas USA Copyright 2010 ACM 978-1-4503-0446-7/10/12 ...$10.00 1 Assuming that the security policies are valid.


In other words, when an inter-organizational workflow is designed, it is a single workflow across multiple organizations.

this single inter-organizational workflow design is split into multiple autonomous workflows, and they are deployed to participating organizations for execution.


Due the fact that each anchored signature may accept several characters at the starting point, the number of anchored signatures increases by 579, resulting in about 167 KB additional memory usage.

compared to the total memory on most of the modern systems, the added memory can be neglected.


5.3 Legal MemoryAccesses Memory isolation mechanismprovidedby CloudVisor ensures the entire memory space of a guest VM is inaccessible to the VMM and the management VM.

there are several cases where the VMM and the management VM should be allowed to access some memory ofguestVMs.


This is also the method used in the prototype described in section 5.


Hence, the user authorization module can be seen as a particular kind of application logic that performs the sole task of determining and authorizing the user.

in this case it is not the XML document access method that is exploited for its deviation, but it is the deviation in assumptions that both modules make.


A few are described in [3], [5] and [10].

none of the existing intrusion detection methods guarantee that an attack will be detected immediately.


These mechanisms perform access control regardless of IP addresses.

in ACL-based access control, each object device must maintain each ACL.


INTRODUCTION Tor is a volunteer-operated anonymity network that is estimated to protect the privacy of hundreds of thousands of daily users [13, 22].

tor is known to be insecure against an adversary that can observe a user s traf.c entering and exiting the anonymity network.


Thus, the privacy risk is always equal to 0 for this solution.

the sharing loss is the absolute maximum, as all con.icting segments, which may be allowed by at least one controller, are always denied.


Therefore, the proposed scheme has a good perceptual quality from the spatial domain.

if one is to alter the other complex conjugate roots, s/he would be altering the low pass or band pass characteristics of an image as well.


The latter point is important in practice, this frequency interpretation of trust /distrust degree can be used as a practical method to calculate trust /distrust degrees, by using the data accumulated in the interaction between a trustor and a trustee.

when the data of interactions are not available or not used, a trust /distrust degree may be given as a subjective probability but with the assurance that the calculus itself is nevertheless correct.


Insecure information .ows via global variables are overlooked.

the system may perform interprocedural analysis by inlining functions before a type-based analysis as we do in experiments in Section 5.


For example, in Figure 3, the number of output function call (echo statement) is three (Lines 3, 13, and 16).

the number of input filtering function (htmlspecialchars) call used in the code is two (Lines 3 and 13).


So only a .that is comparable with N has any real e.ect.


Clearly,thesmartphoneisnottheonly choice.Agenome could also be stored at a physician s of.ce.

an individual may visit many types of medical specialists and/or change physicians.


The work reported in this paper builds on a previous paper by us [1], where we develop the technique for authenticity veri.cation that we use in the current paper.

the current paper signi.cantly extends our previous work with techniques for con.dentiality and completeness enforcement.


Our main approach is to use lazy evaluation to identify the essential measurements required from the underlying privacy mechanism to evaluate an expression.

the languages we considered exhibited a tension between lazy semantics and transparency of evaluation: lazy languages were less inclined to violate referential transparency, concealing whether a measurement was truly needed for an evaluation, while strict languages such as F# [1] make it cumbersome to write lazy programs.


Also, note that in a typical real world scenario, direct interconnections of hosts (between two networks) that exhibit vulnerabilities would not be allowed.

in order to see the forest through the trees, for this example only, such direct interconnections are allowed.


HILTI s runtime associates with each virtual thread a separate array that contains a copy of all thread-local variables.

as one compilation unit might access threadlocals de.ned in another, only the link stage has the global view necessary to determine the .nal layout of that array.


The alphabetical path, however, shows our unsupported MSI request (a), which the platform detects and blocks.

when System Error Reporting is enabled, the platform sets the SERR status bit on the Memory Controller Hub (MCH) PCI Device (b).


Unfortunately, for this multi-ciphersuite simulation to work, it is essential that public keys not be shared across ciphersuites: this technique could show that switching between an RSA-based ciphersuite and an ECDSA-based ciphersuite is safe.

to analyze using the same RSA public key in two di.erent ciphersuites, one would have to take an alternative approach, as it may not be possible to generically prove that re-using the same public key in two ACCE protocols is safe.


We call this function decide, and de.ne it as follows, for nodes xA,yB and transaction a with risk r. decide(A, B, ar)= if r = t(A, B) then perform else abandon  3.3 Dynamic Response to Policy Changes If we were to leave the security policy as de.ned up to this point, it would be a static policy, never changing once deployed to a network.

wSNs are often subject to dynamic forces beyond the control of the designer, and a comprehensive security policy that can adapt to those changes quickly and e.ciently would be a tremendous advantage.


It propagates labels de.ned at the OS layer across systems, throughout label enforcement at the network layer.

dStar does not integrate enforcement at the application layer, although that is mentioned as future work.


The authors define a set of principles guiding the design of secure vehicular communication.

the general guidelines are not specifically dedicated to usages.


As only veri.ed CDIs are provided to TPs, one may think that nonveri.able CDIs should be simply deleted.

it is too simplistic to assume that any non-veri.able CDI item can be deleted, as other data or perhaps the system may depend on the CDI items.


Since it is difficult to input complex strong passwords on smart phones, weak passwords (e.g., 4-digit PIN) have been widely used for user authentication.

it suffers from brute force attack due to its low security entropy.


Obviously our idea is not a completely novel idea; prior work in the area has had a similar goal.

most of those attempts have not properly addressed the requirements for the trusted system, generally preferring to use existing generalpurpose systems even when on a "dedicated device."


Thus, the state transition probability distribution should be given by the conditional probability Pr(7tI7t-1,Yt,zt)for each quadruple (7t,7t-1,Yt,zt).

since the size of the domain of the quadruple is very large for practical applications, it is not appropriate to de.ne the conditional probability by hand.


Poisoning Behavioral Malware Clustering Battista BiggioKonrad Rieck Università di Cagliari University of Göttingen Piazza d Armi Goldschmidtstraße 7 09123, Cagliari, Italy 37077, Göttingen, Germany battista.biggio@diee.unica.it konrad.rieck@unigoettingen.de Davide Ariu Christian WressneggerIgino Corona Università di Cagliari University of Göttingen Università di Cagliari Piazza d Armi Goldschmidtstraße 7 Piazza d Armi 09123, Cagliari, Italy 37077, Göttingen, Germany 09123, Cagliari, Italy davide.ariu@diee.unica.it christian.wressnegger@ igino.corona@diee.unica.it cs.uni-goettingen.de Giorgio Giacinto Università di Cagliari Piazza d Armi 09123, Cagliari, Italy giacinto@diee.unica.it ABSTRACT Clustering algorithms have become a popular tool in computer security to analyze the behavior of malware variants, identify novel malware families, and generate signatures for antivirus systems.

the suitability of clustering algorithms for security-sensitive settings has been recently questioned by showing that they can be signi.cantly compromised if an attacker can exercise some control over the input data.


Prior work [31, 6] reported the results of applying static analysis to 10 12 carefully selected packages.

in the experiments reported here we have applied our tools to all C/C++ code in the Debian Linux repository, and completed analysis of 3,692 packages.


It is mainly because of two reasons: (1) voice is time sensitive media and (2) its presentation requires at least several thousands bits of information per second.

if we could show that it is possible to hide a telephonic conversation by creating a covert communication channel within another (i.e., cover) conversation, without using LSBs or any other previously known audio steganography methods, it will have profound effects on call monitoring and media interception.


Intuitively, this approach might seem to reduce the accuracy of inference.

in examining Equation 1 derived in Section 3.1, we see that the dummy nodes in a given user s public list only add an additional constant term to the expected value of ...., which will not a.ect edge coverage attacks which only consider the ranking of nodes by .. (..).


Therefore, if there is a safe disclosure sequence G according to Alice s original policies, then after the above policy migration, G is also a safe disclosure sequence according to the covering policies.

suppose that according to the disclosed covering policies, there exists a safe disclosure sequence G. Since Alice never discloses the policy of C*, G does not involve C*.Let Ci be a disjunct of R s policy that was satis.ed before Ris disclosed in G. If the original policy of every credential C in Ci is satis.ed before C is disclosed, then G is also a safe disclosure sequence according to the original policies of Alice.


If all consumer devices would support cryptobinding, this method would probably be the best way to mitigate our attack.

from our experiments we concluded that Apple devices do not support cryptographic binding at this time.


These plg(t +1)l bits are in e.ect programmed into the card when the authority issues it.

note that the authority cannot alter these pre-programmed bits once the card is issued, since the strong minimality property from [10] (which is encompassed in our condition 5 above) prevents the prover from learning any information from the veri.er during the protocol.


The results describing the estimated user interaction time are necessarily speci.c to our system.

our system provides integrated support for resolving miscon.gurations at the time of access.


The Judge acknowledges that the suspicion of one or two employees does not require an entire company to preserve evidence.

the Judge inferred from the evidence presented that the relevant people at UBS anticipated litigation in April 2001.


Software exceptions, model-speci.c registers, and the cpuid instruction are not generally treated as inputs in previous replay systems.

it is extremely dif.cult to emulate them right.


At the meeting point, the adversary is uncertain about how to make a link between the observed events immediately before and after the meeting.

the adversary s uncertainty in reconstructing other parts of their trajectories is low (because their trajectories are far from each other in other parts).


A straightforward solution is to copy the security manager and the isolated workload out of the SMRAM to an unprotected memory.

this will introduce an unacceptable performance overhead.


Deniable AKE convinces two parties of each other s identity during the protocol execution, but does not allow either party to convince anyone else that authentication was successful, and therefore provides repudiability.

mpOTR provides repudiability properties which are weaker than the two-party version.


Since shadow objects are linked to real objects, when the real object becomes unreachable, the shadow object automatically becomes unreachable.

the use of shadow objects still presents a challenge during garbage collection.


Hence, these threats are not covered in this paper.

there are no appropriate mechanisms for preventing denial-of-service (DoS) attacks on a mobile device.


The browser need only recognize the re.ected script and block the attack.

there are a number of challenges to building a .lter with zero false negatives, even for a restricted set of vulnerabilities.


The discovery that code and data can be systematically interchanged was a key advance in early computer design, and that dual interpretation of bits as both numbers and commands is inherent to programmable computing.

all that .exibility and power turn into security risks if we cannot control how and when data become interpreted as code.


Our dataset exhibits the patterns one might expect: the average battery life of infected devices 16 http://bit.ly/IDjWos   was less than that of clean devices and the average number of installed applications on infected devices was larger than that in clean devices.

the di.erences were not always signi.cant.


INTRODUCTION Cloud computing pursuits the goals of broad network access, on-demand self-service, resource pooling, rapid elasticity, and measured service [2].

the security of all of these services depends on properly isolating trusted from untrusted code.


For rewriting the application binary and enforcing CFI, we base our implementation on our MoCFI framework [11].

we need to extend MoCFI to introduce the policy enforcement and the runtime Objective-C analyzer.


The manufacturer claims that the bitstream encryption as implemented in Xilinx Virtex-II Pro FPGAs can thwart even most Class III attacks [28], i.e., attacks by wellfunded intelligence agencies [5].

our research does not support this claim as shown in Sect.


The architectural modi.cations we devise are designed to sit between cache and CPU in a single unit that can be added to a processor core without modifying either the instruction set or the rest of the architecture.

some optimizations are possible if one is willing to modify the instruction set (for setting dynamic memory permissions) and CPU (to optimize the instruction pipeline for performance).


The details on the techniques used to perform this mapping are not provided in the paper.

we attempt to map all disk blocks in the protected storage back to actual applications and hence the scope for TimeCapsule is much larger.


This is because MyPage-Keeper has a limited view of Facebook data the view provided by its subscribed users and therefore it cannot see all the malicious apps present on Facebook.

during the nine month period considered in our study, MyPageKeeper observed posts from 111K apps, which constitutes a sizable fraction (over 20%) of the approximately 500K apps present on Facebook [25].


The ARM architecture is a 32-bit architecture, hence it is imperative that the operands of instructions must be able to span the entire 32-bit addressing range.

since ARM instructions are 32 bits and a number of these bits are used to encode the instruction OP code, operands and parameters, operands that represent immediate values will never be able to store a full 32-bit value.


Similarly, if a CA gives a third party access to its records, individual privacy would be compromised.

these actions would not enable the impersonation of an individual since the attacker still would not have access to the individual s private key.


The threat of EM display stealing from tablet PCs has not been discussed in conventional studies because tablet PCs have weaker EM emissions than conventional PCs do and such weaker EM emissions seems to be reduced to the noise floor quite close to the devices.

our experimental results clearly identify the security hole of tablet PCs based on such EM emissions.


2) Time-to-time call detail records (CDRs) are analyzed to discover any anomalous subscriber behavior (i.e., sudden spike in the number of calls to Cuba, Jamaica etc.).

it should be noted that such fraud is not easily detectable, and when detected it is already too late as signi.cant damage has already been done.


It may be good for users to be able to update all information at one time for their convenience.

it might cause the problem if a cracker happened to interpolate the files just at that time.


No authentication protocol protects against such attacks and therefore our protocol does not have special measures to prevent it either.

our protocol does offer protection against a manin-the-browser attack that tries to obtain the user s credentials.


This problem is not critical, because it is related to bodies of malware while our main goal is to detect a dropper in due time.

we are going to continue research in this direction to clarify the situation.


In particular, the model information from the training phase helps mini () ßj -aj mize the term +1, and also ensures that the do .j main [ßj aj] is traversed in intelligent order (by prioritizing the most likely combinations).

the baggage of the exponential term (2n - 1) is still massive as n grows.


For policy , neither authentication nor confirmation of agreement are required, so all of the five methods meet the conditions.

some methods require superfluous authentication.


A gray-box detector extracts additional runtime information from the process, e.g., by looking into the process memory (e.g., [3, 15]).

white-box approaches obtain the model by statically analyzing the source code or binary (e.g., [2, 6, 7, 18]).


Some systems implement many-to-one mappings to support shared memory; e.g., transparent page sharing maps multiple GPPNs copy-on-write to a single MPN [4, 30].

existing virtualization systems do not provide .exible support for mapping a single GPPN to multiple MPNs.1 Multi-shadowing is a novel mechanism that supports contextdependent, one-to-many GPPN-to-MPN mappings.


RELATEDWORK Many effortshavebeen devoted topolicy composition[6,7,16, 19, 21, 12, 13, 8, 21].

for very few of these approaches, the expressive power has been analyzed.


Biometrics authentication method is one of the solutions for personal identification.

it requires special devices such as fingerprint recognition devices or vein recognition devices which increase the price of smart phones.


Given these facts, it is perhaps not surprising that these applications are the ones which are most likely to contain privacy-related API calls.

it also indicates that the average app install is more likely to contain these calls than might be otherwise expected, as the more popular apps are proportionally more likely to be installed on any given device.


Similar considerations apply to other federated identity management frameworks, such as OpenId [10], Higgins [13] and Shibboleth [4].

as highlighted in [10, 3], lack of user control over personal data is a great concern in identity management.


[12] proposed a updatable threshold encryption scheme, which is useful for sharing a secret between leaky devices.

their motivating scenario is that all devices are owned by a single entity who also decides the threshold (actually, a general access structure), but not the encryptor.


[1]); 2) anonymization methods (e.g., k-anonymity method proposed by Sweeney [14]) that yield a sanitized version of the original data set.

successful attack strategies against proposed solutions in both directions necessitated new definitions of privacy and anonymity.


An advantage of the tmp directory is that the system will delete all data stored in the directory when the user exits the application.

the ABE-encrypted CCR can be written in the application s local .lesystem and remain self-protected due to the ABE encryption.


Recently reported techniques address these challenges considering secure test and IP core protection separately.

for ensuring high security during IP core functionality and also during test, joint consideration of secure test and IP core protection is much needed.


A tree-based solution is suitable for software implementation because dynamic memory management is relatively easy.

it becomes extremely di.cult when implemented with hardware.


CompChall would not adversely affect legitimate users since their authentication attempts are expected to be limited.

the scheme may negatively impact an attacker when a large number of attempts are made from a single machine.


In summary, one way to overcome these three obstacles is to add the VMBus driver support to the BIOS, rewrite the BIOS to remove its dependencies on devices which are not needed for the cloud, and paravirtualize all the guest OSes to no longer attempt to initialize devices at boot time other than the synthetic NIC and disk.

such a plan requires a drastic amount of effort, comparable to implementing and testing a new release of a commodity operating system.


For Case 2, the average similarity score is a little bit lower than Case 1.

there are four apps that cannot .nish the whole serialized obfuscations.


In case the request cannot be satisfied, the reser- vation requested by that Receiver is cancelled.

the feedback message would still be sent.


This kind of permission-centric delegation may be useful for certain cases.

integration of these two types of delegation into our framework will dramatically increase the complexity of model.


So on the one hand, user prompting provides mediation for every single resource access attempt by the application and is totally dynamic.

users may become frustrated or annoyed by frequent prompting.


Obligations to Enforce Prohibitions: On the Adequacy of Security Policies Wolter Pieters Julian PadgetFrancien Dechesne Delft University of Technology University of Bath Delft University of Technology & University of Twente United Kingdom The Netherlands The Netherlands jap@cs.bath.ac.uk f.dechesne@tudelft.nl w.pieters@tudelft.nl Virginia Dignum Delft University of Technology The Netherlands m.v.dignum@tudelft.nl ABSTRACT Security policies in organisations typically take the form of obligations for the employees.

it is often unclear what the purpose of such obligations is, and how these can be integrated in the operational processes of the organisation.


In order to increase trust within a community one would like to import good reputation values and good credentials from other communities.

these may expose the details of the reputation values and thus impair the user s privacy.


Numerous communities and federal scienti.c repositories provide open or coarse grained security access for their members2 .

a more elaborate design is necessary to support a shared, secure Cloud data repository supporting multiple data owners and consumers, hosted on an untrusted Cloud storage provider, and with no central authority privy to plain text data.


This optimized case introduces an interesting challenge: a traditional 0x80 would force a VMExit (thereby allowing one to trap the call), but fast syscalls on modern hardware virtualized platforms do not induce a VMExit.

syscalls must still retrieve the target entry point (in the VM s kernel) by examining a well-known machine speci.c register (MSR)1 .


biometric only, authentication to the right.

accuracy enhancement in case of secure keys two-factor authentications results in much higher FAR if user-based key is compromised.


In typical use, we expect the EXECUTE bittobeusedwiththe INCRE-MENT mode so that using a clob requires incrementing a counter.

it may also be used with the READ mode to allow us to create clobs that do not require the counter to be incremented each time they are used.


On the one hand, it is possible to cover a long network lifetime.

the compromised member can be revoked immediately.


As stated previously, organisation theory typically has an implicit view of organisations as sociocultural systems.

in order to conceptualise the interactions between culture and policies at a su.ciently granular level, a more detailed conceptual framework is required.


Although it captures many of the best practices in modern software development in a form that is suitable for a wide range of projects and organisations, it does not specifically address security.

the following six best practices are of significant importance to software development in general, namely [18]:  Develop software iteratively.


However, it requires a trusted language-speci.c environment.

we target runtime attestation of arbitrary program binaries independent of their programming language.


Since users can view fingerprints as a sort of "crypto address", they should be quite comfortable exchanging them, importing them into address books, notifying people when they change, and so on.

schemes which try to simplify things through automation end up forcing users to grapple with the concepts of keys, signatures, certificates, certificate chains, revocation lists, trust roots, and validity/trust calculations.


All participants were required to have used mobile devices prior to the study and were asked to follow the same procedure detailed below.

only the interactions of 10 of the participants were used to build the multiclass classi.cation models whereas all 20 participants were used to test for unary classi.cation.


At .rst glance, the results appear sobering.

a closer examination of the result reveals interesting insights.


{P1,...,Pn}, Ris a set of uris, and Pi,1 =i=n, is an IBLP.

to simplify the notation that is used, in the remainder of the paper Ai < .i is interpreted as a shorthand form of Ai < d(.i), and as shorthand for referring to the evaluation of Ai with respect to the IBLP Pi that is identi.ed by .i.Henceforth, .i will be used to denote the IBLP Pi.


Our main goal is to design an authentication framework withprivacy-preserving and single sign-on (SSO)properties.

since anonymity necessarily introduces an avenue for abuse, we must go a step further than existing SSO frameworks (e.g., OpenID [6]) and provide mechanisms to phone number (top).


if several new nodes form a long path, as shown in Figure 4(b), a PDoS attack can cause more damage.


[Vogt 2007] also track information .ow control at runtime to prevent cross-site scripting attacks.

they have limited their system to client-side changes only, and therefore cannot prevent attacks that move data back and forth between the browser and server.


If high deniability is required, the .le system should be con.gured with enough resources to prevent it from becoming overloaded.

to support a heavy workload, we could con.gure DRSteg for a lower deniability assurance.


In fact, we represent the adversary s knowledge by PrA(.).

the construction of an adversary s knowledge (i.e., computing the values of PrA(.))


The above claim holds only when we consider the architecture in isolation.

in real world this is never the case and it is possible for the underlying framework to have covert channels.


Instrumenting a network driver with LXFI increases CPU usage by 2.2 3.7×, and achieves the same TCP throughput as an unmodi.ed kernel.


An analog simulation can provide a precise knowledge of the impact of transitions inside 0-7695-0993-2/2001/$10.00 &#169; 2001 IEEE such a coupled system.

its is well known that making such a simulation is unrealistic even for a hundred thousands transistor circuit.


In the studied case of social login one could argue that the retrieved personal data might only be kept until access to the application (and consequently the company network) is granted, since the purpose of the processing of the social network data is limited to the social reputation update, and maximum maximorum to the access of the company network, which is the ultimate goal of the social login.

this does not necessarily exclude the possibility to keep the data for a longer period of time, even in a non-anonymized form.


SecurIT 12, August 17-19, 2012, Kollam, Kerala, India  Copyright 2012 ACM 978-1-4503-1822-8/12/08... $15.00 learning [2], sequential change-point detection [3,4] and so on.

due to those techniques overlook the dependencies and correlations between features, they commonly suffer from an issue of high false positive rate.


The focus was put on the transaction properties.

rBAC models have important features that deserve consideration when updating.


This, in turn, reduces the likelihood of content leakage.

the lack of an organised information system and/or a systematic information .ow increases the likelihood of content leakage.


[3] rely on the fact that adversary strategies need to information-theoretically hide the secret.

this restriction is unnecessarily strong, since the prover could forward information about the secret which does not help the adversary in future authentication sessions.


Sensor nodes have limited computation resources, so an ideal protocol would have low computation overhead for both sender and receiver.

there exist scenarios where computation might not be a particularly critical issue.


This framework has much in common with other techniques, de.ning systems based on state machines and building various types of simulations between them.

rather than commit to a single set of properties preserved by those simulations, the set of security guarantees to be preserved is a parameter of the analysis.


Note that, similarly to the existing advertisement model, a third party could mediate the exchange between online services and their computing partners.

unlike the targeted advertisement model where the (privacy-invasive) user pro.ling increases revenues, our framework does not   Figure 1: Example of using microcomputations as a payment scheme in online newspapers.


Our goal is to help network administrators to extend their understanding of network anomaly detector behaviors.


Our another scheme .2 can alleviate this prob cibe lem: Its CCA-security is based on the GBDH (Gap Bilinear Di.e-Hellman) assumption, which seems to be milder assumption than bilinear inversion assumptions as discussed in [7].

.2 needs pairing and hashing into G op cibe erations to be performed.


Properly implemented cryptosystems can o.er strong security assurance even when the communication could be eavesdropped.

as NFC is usually considered physically secure , many upper-layer protocols of NFC applications do not implement encryption or only adopt short keys in encryption algorithms (such as DES [3]).


Uptil now, we have considered them primarily within a single AP and multiple RP scenario.

they may be equally used within a single RP and multiple AP scenario.


For instance, we .nd that many frequently occurring irrelevant tokens, that are not in the blacklist B are speci.c to the phone at hand and hence no generalized rules can be hard-coded to avoid them.

owing to high frequency, they have a low IDF score and would therefore have minimal impact on the quality scores.


Motion-MIX ensures perfect identity anonymity.

this paper does not study anonymity guar 1Readers who are familiar with Shannon s perfect secrecy [40] can see the similarity between Figure 6 and Shannon s depiction.


For example, it would not matter whether the application was Webbrowser A or B, as long as both have the same properties.

the binary attestation function provided by TCG-compliant hardware attests the system con.guration of a platform that was determined at system startup.


2 B is a malicious agent in terms of reading psw, which he is not authorized to.

b writes a piece of malicious code into the obj.


For instance, if for some reason a real event is not registered, we say that the event was deleted by the logging protocol, whereas if this event is registered, we say that the event was logged.

if the logged event is different from the real event , we say the event was substituted.


Access control to XML documents is the foundation based on which access control for the Semantic Web should be built since the Semantic Web is built upon XML.

when applied to the Semantic Web, the existing access control models to XML have to be extended to take into consideration the higher layers of the Semantic Web architecture [3] above XML (see Figure 2), such as RDF and ontologies.


If we focus on the data behavior in benign execution, it is in fact a problem because the runtime kernel behavior is highly dynamic across di.erent runs.

we focus on the data behavior of kernel malware that consistently appears only when the malware is active.


(2) From the viewpoint of cloud service users If the cloud service user can determine the variable security level that the cloud security visualization system provides, as shown in Figure 8, the user can quickly start investigating a switch to a different cloud service when the level seems to drop.

this will increase the load of the cloud computing environment even more, and the service may stop when, for example, the cloud service user begins to back up data all at once at the time of the level drop.


Packet P3 from flow F1 gets a match on FPGA, so the flow entry of F1 is updated directly on software which means that a signature is detected in that flow.

since P1 and P2 are tagged as UNMATCHED by hardware, they will be forwarded to the reassembling buffer and matched again by software.


One possible attack to consider is a group of colluding administrators performing an installation on an untrusted machine.

the intent of the k-of-n secret sharing is that k must be large enough that forming a colluding group of that size is unlikely to happen.


Example guest con.guration (Linux): iwcon.g essid $ESSID mode ad-hoc key $WEP10 ip route replace default via 7.7.7.8 dev wi.0 Example escort con.guration (Linux): echo 1 >/proc/sys/net/ipv4/ip forward iwcon.g wi.0 essid $ESSID mode ad-hoc key $WEP10 route add -host 7.7.7.7 dev wi.0 iptables -t nat -A POSTROUTING -o wi.1 -j SNAT --to 8.8.8.8 It is obvious either wireless segment, namely guest-escort segment or escort-infrastructure segment, can be replaced by a wired connection.

this obviously impedes the guest s mobility in the wireless LAN.


In particular, one can show that using a constant number of control points, spline based constructions may in the worst case su.er from unbounded tightness.

in practice as we increase the number of control points, the spline approximation becomes very tight.


In security-critical environments such as government and military institutes, classi.ed documents are isolated by using physically separated computing platforms.

in typical enterprise environments users perform these tasks using one computing platform providing a questionable isolation between them.


Since the message exchange required by the protocol can consume considerable network resources, we integrate our detection scheme in the AODV routing protocol by adding new routing messages and procedures to gather trust ratings by other network nodes and compute the global trust of the other mesh routers.

we observe that the proposed framework can be implemented in any routing protocol and used to choose the most trustworthy path, when more alternatives are available.


Its simple-security property prevents subjects from reading objects of a higher security (secrecy) level (no read-up ) and its *-security property prevents subjects from writing object of a lower security (secrecy) level (no writedown ).

biba integrity model protects data integrity by enforcing a simple-security property that prevents subjects from reading objects of a lower security (integrity) level (no read-down ) and a *-security property that prevents subjects from writing objects of a higher security (integrity) level (no write-up ).


RELATED WORK In the computer science literature, there are isolated reports of physical penetration tests using social engineering [3, 4].

these approaches focus completely on the actions of the penetration tester and do not consider the impact of the test on the employees.


Usually, this kind of search engine optimization (SEO) aimed at increasing pagerank is frowned upon, since having irrelevant results leads to a worse user experience.

we believe our approach to be mostly innocuous because we speci.cally target search queries that are issued by malicious attackers.


An attacker is highly vulnerable to detection during these early steps.

once a properly constructed and victim-tuned rootkit is installed, the infected system is in extreme danger.


The involved roles in this trust model are: Identity-CA: Similar to the TCG proposal, the Identity-CA (ICA) identi.ed by the key pair (PKICA,SKICA)is responsible for providing identities or pseudonyms of platforms involved into the property-based attestation protocols.

in a centralized enterprise environment where the IT department owns all client platforms, anonymity is not an issue.


The result is that the models are speci.c to a small set of benign applications (those that were used for training).

they fail to identify activity that is common, and characteristic, to benign applications in general.


delete_call_ forwarding appears to be an even better candidate due to its lower response time.

delete_call_ forwarding messages can only be sent if call forwarding is already enabled.


This may imply that the countermeasure based on request randomization integrated in the TBB [24] may not be e.ective.

when we evaluate 2.4.7 we observe low accuracies for combinations with 3.5.


This would provide a small computational gain if one considered public key validity check could be pre-computed.

this would imply reducing the scheme s security to the less standard variant of the GBDH problem used in [1].


The computational complexity of this brute force attack is on the order of o(2(128-n)).

since this protocol does not provide any proof on the authorization of MN to use the particular HoA, it is not able to protect against the malicious mobile node flooding attacks.


We are using the Enterprise Role-Based Access Control Model as our basis.

the presented concept is more general and can also be incorporated into other RBAC models.


A compromised hypervisor may attempt to disable SMI by overwriting GPI_ROUT.

this can be easily detected by the remote user due to the lack of response from HyperSentry.


The strength of static taint analyses is that they can prove the absence of taint violations, or at least delimit the regions in which they may happen.

sound and precise static analysis of modern scripting languages is hard.


It is conceivable that an optimizing compiler could also detect this optimization opportunity.

there will always be cases where the programmer knows more than the compiler, and thus can do a better job placing registrations.


probability needs to be brought down to a fairly small value.

tag,ktag the analysis in the last section show that to achieve Theorem 3.


Similar to prior work on Android, PMP enables users to decide .ne grained privacy protection settings on a per app basis by allowing suitably anonymized data to be sent instead of privacy sensitive information [3, 14, 31].

a crucial di.erentiator of PMP as compared to prior work is that we have developed a crowdsourced system to collect and analyze users protection decisions to help make privacy recommendations to users.


4 shows that the estimation becomes inaccurate as c increases.

there is a big gap between the two attacks: the minority collusion seems to be easier to estimate than the worst collusion.


The specialpurpose algorithm explicitly considers all authorized6 critical prefxes of valid schedules and checks whether the next obligation in the schedule is authorized.

the model checking approach models the execution of a set of obligations as a fnite state machine (FSM) and checks the accountability property, as specifed by a temporal logic formula.


For instance, approximately 70% of the female users had no paid apps installed while the corresponding value is only 50% for male users.

when the money spent increases the di.erence in the gender distribution decreases.


We found that login times for No-Shu.e Object PassTiles were signi.cantly shorter than those in Ob ject PassTiles.

the average login time was approximately 20 seconds, which was still longer than average login times for Image PassTiles.


DAEl ··· DAE1 f is applied to PaPB|=MP4 ., where .

= DAEn ··· DAEl DAEl ··· DAE1 f. From the induction hypothesis, index[AEt] =|AEt| for 1 = t = n. for, 1 = t = n, either index[AEt,q] = index[AEt,.]


This makes sense, since static analysis only compares policies and does not consider the instances.

as the number of instances gets very high, it appears that the relationship is not entirely constant.


For example, this philosophy is adopted by our policy of gradual release [AS07], which rejects the program above.

the rationale of localized delimited release, for a given piece of data, is to disallow data release before it is declassi.ed but, on the other hand, allow release to take place any time after declassi.cation.


Because our ORAM construction protects the privacy of the access pattern, the access pattern will have no distinguishable e.ect on the performance of the clouds.

the access pattern can a.ect the size of the client s internal data structures (up to a certain point).


on the NIST images and found every process data structure with minated processes whose EPROCESS structure was still in memory no false positives.

only our own scanner was able to and had not yet been overwritten.


Hence, several previous works deployed lightweight ad-hoc designs of compression functions and PRNGs, however, without analyzing the underlying requirements on these components and their interaction.

we identify concrete su.cient requirements.


In most scenarios we took the average load over a three minute period.

to account for the uneven CPU load during token calculation in our solution, we took the average over the entire 20 minute time period when tokens were being computed.


Finally, the nurse Claire may not be involved in the dispensation due to her drug abuse history.


It is outside the scope of this model to cover how b is securely conveyed to Bob.

there are many traditional encryption schemas that can be used to maintain the necessary confidentiality and integrity.


Their approachis relatedtotheACPextraction of our approach, since both use patterns to extract information.

their patterns are based on the low-level POS tags (such as NP andNPList), while our semanticpatterns arebased ongrammatical functions ofphases(such as subject, main verbgroup, and object).


Thus, locked SOP is designed to specifically mitigate attacks when both legitimate and malicious content are downloaded to a browser.

locked SOP cannot mitigate man-in-the-middle attacks in which all content are downloaded from malicious source.


Such schemes = are said to be t-collusion resistant.


Therefore, we explain the case where HTML form tags are used.

constructing our scheme based on other password-based authentication mechanisms, such as HTTP basic authentication and HTTP digest authentication [3], is possible.


The next two layers, the network and application layers, also have additional, optional security capabilities.

even if the security suite is resistant to successful attacks, its strength is limited by the confidentiality of the key used.


In particular, with the advent of Web 2.0 era, people not only extract knowledge from various information sources, but also contribute and share their own generated contents.

web contents are typically published without being seriously fact-checked, thus greatly in.uencing people s daily life if non-credible web contents are relied on to make decisions.


Web tripwires [27] verify the integrity of a page by matching it against a known good representation (either a checksum or an encoded copy of the page s HTML), using client-side JavaScript to detect in-.ight modi.cations.

web tripwires have a high network overhead (approximately 17% of the page size), which could hinder the end-to-end response time, especially for slower networks.


2) Many of the queries issued to the root come from public recursive DNS servers that are responsible for a large number of queries aggregated from potentially multiple users, where the individual users IP addresses are detached, thus the root does not see those address.

this still puts the individual users at risk, although their individual IP addresses are not exposed.


Our PoC can achieve FRR of 10% at FAR of 0%.

to obtain longer keys, we decided to choose the threshold corresponding to FRR of 19% at FAR 8To avoid reporting outlier results on random hyperplanes, we report the average of 5 tests, using a di.erent set of 512 orthonormal hyperplanes each time.


Injected instruction sequences that have not been correctly encrypted will result in irrelevant or invalid instructions after the obligatory decryption.

correctly encrypted code will be decrypted and executed normally.


There are various methods for constructing the aggregation tree according to different application requirements.

sDAP does not rely on a speci.c tree construction algorithm as long as there is one.


Once all security associations have been dropped successfully, the program that caused the trip executes normally.

if any security association lingers, the tripping program will sleep inde.nitely, and the privileged user will be unable to execute any untrusted programs.


to provide monitoring of VMs, allowing easier security manage ment of complex cluster, server farms and cloud computing infrastructure.

it can also create new potential concerns with respect to security.


scheme [3] uses deployment rectangles whose sizes strongly depend on the pdf of node deployment.

our scheme does not use such rectangles; instead, it uses a key-position map andthe pdfofnodedeployment.


The sequence of system calls made along a normal program path has to be a normal system call sequence, which means system call sequence based scheme cannot detect any attack undetected by anomalous path checking.

a normal system call sequence does not guarantee a normal program path.


So, the maximum pointer de.nes the size for all elements.

almost all elements store smaller pointers that could be represented in a smaller memory.


We could use F-1 a clause like G-1 (open-f _ create-f) for two events open-f and create-f, representing respectively the opening and creation of a .le with name f .

this only encodes the requirement that for a .xed f , .le f must be created before it is opened.


An approach to prevent information over.ow in this huge information supply is the provision of personalized information supplies.

this approach carries critical risks concerning information security.


In this particular checklist, each subsection was given equal weighting relative to the other subsections.


Even without caching message identi.ers, timestamps provide a cheap way of avoiding replays outside a time window.

such mechanisms fail if the  header or the  security header may be tampered with.


In principle, smart cards could run multiple trusted services.

they would share the limitations highlighted in this paper for both ARM TrustZone (i.e., all communication is mediated by the mobile OS on the device) and SIM cards (i.e., constrained computational power and memory).


Thepriorwork thathasstudiedaccountability[8,9,15,16] focused on several technical problems.

the architecture of a user obligation management system has never been presented.


Both the authentication key and the access key are updated after a successful session in order to give backward untraceability.

the scheme still permits backward andforwardtraceability,because a strong attackerthat compromises a tagcanidentify a tag spastinteractionsfrom the previouscommunicationsand the .xedEPC of thetag,and canalsoread thetag sfuturetransactions.


The low false 0.3 negative rate suggests that FBCluster is able to detect most 0.2 0.1 spam in our dataset as spam URLs are often shared by spam 0 0 50 100 150 200 250 300 350 Time (day) # of Posts  (a) New users created every day(b) Cumulative distribution of post number by spammers/nonspammers Figure 1: Statistics of a social blog dataset  2.2 Evaluation of AutoRE 1 posts.

the high false positive rate indicates that FBCluster has mistakenly included a number of non-spam posts in the detected spam clusters.


A storage system that is intended to keep data secure for several decades must thus be able to adapt to these changes by incorporating new technology and migrating data from outdated components.

it must do so without allowing any party to actually recover data.


Since malicious websites always are web island which are not linked in by other normal websites, usual detection programs cannot .nd them through webcrawler.

dNS query logs can record all the websites only if theyare visited once by DNS server users.


measuring the shape of the ear channel using acoustic data).

we found the current physiological biometric solutions to be affected by one or more of the following problems: (i) non transparent usage; (ii) performances are heavily in.uencedbyexternalfactors such as illumination, position or occlusion [20];(iii) lackof required hardware on current smartphones.


Since the Storage Host does not rotate, the attack code can remain inde.nitely.

since the Storage Host cannot be reached from external sources, any information must be transmitted via a compromised Service Host.


This allows attack graph abstraction at various levels, from high-level overviews to low-level details.

the effectiveness of interactive attack graph exploration depends critically on the particular visual (as opposed to mathematical) representations used.


s and Lee and Chiu s schemes and resists different possible attacks.


Any of the 24K candidates that are covered by the IRSF list is considered as a true detection (or a truepositive).

we consider a missed detection when a phone number from the IRSF list appears in the data but not among the 24K candidates.


have shown, people tend to disregard SSL indicators, leaving them vulnerable to phishing attacks [15].

studies have not focused on design .aws that would prevent even the most educated user from being able to make the right security decisions.


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

we require that once the function and a subset of parties is chosen, the cloud performs the (expensive) computations noninteractively, without help from any of the users.


LoPA and DiPA solved the same problem (i.e., aggregating data from several meters), which is also addressed by a number of other existing protocols in the literature [4, 3, 5, 9, 10, 11].

the billing protocol allowed for the computation and veri.cation of the monthly bill of an individual house 1A large amount of this implementation has been done by George Danezis from Microsoft Research.


At .rst, it seems obvious we can use a debugger.

this is not the common functionality most debuggers provide.


Since our goal is to ensure that a malicious user doesn t learn any unintended information, the above de.nition is similar to what is termed sender s security in [27] and vendor s security in [2].

we di.er from both notions in that inference channels are a more general concept than the query counts in [27] and the query prices in [2], that determine access controls in those works.


They also suggest it might be possible to construct a worst-case secure LWE-based encryption scheme with polynomially bounded uniform error.


In principle, the read (or any other system call) could be handled in the same manner.

since the behavior of read does not need to change for our attacks, we rely on normal input redirection or socket behavior to supply the necessary data.


7.2 Attacks it was shown on section 6.1 that to get a token from a transaction token is not a trivial problem.

the strength of the algorithm resides on the hard problem of generating a grammar from tokens.


Meanwhile, a large amount of effort has been made to overcome the problems caused by imperfect CSI [11, 28, 39].

none of these have considered the vulnerability of CSI feedback.


From the existing metadata standards and metadata models, only the Functional Requirements for Bibliographic Records (FRBR) [18] and COMM consider the separation of information objects and information realizations [8], i.e., the separation of an information object like an image and its multiple realizations.

it is not fully supported in FRBR as the annotations can only be applied on the information objects.


Many organisations recognise their ability to create a more secure, trustworthy environment by implementing and enforcing an internal set of best practices, together with achieving legislative compliance.

this can only be achieved if software developers are educated in security issues.


In fact, for currently best-known TDP-based encryption methods, one either has to lose exact security [25] or has to pad the message to be longer than the length of the TDP [16].

we commit to m once and then apply a deterministic, length-preserving Feistel Transform to obtain the required w and s. Moreover, we are guaranteed to always obtain tight exact security.


Overall the accuracy of our new scheme is very close (1.4%) to what our MTurk experiments predicted.

our MTurk evaluation failed to reveal infrequent confusion between 0 and 8, due to the relatively low prevalence of captchas where the confusion might occur (< 1%).


Physical penetration testing using social engineering can never be completely respectful because it is based on deception.

the deception in both methodologies presented in this paper is justi.able.


This attack is more involved and therefore harder to .nd in the wild.

if this attack is successfully executed, it results in very stealthy malware because the malicious application itself does not contain any dangerous permissions.


Such microSD cards enable solutions that reach a large number of users because they can even be used on phones without an integrated NFC interface.

microSD cards with integrated NFC are hardly available and most stock phones are not equipped with NFC antennas.


For the case when two parties send di.erent bits, the attacker will not be able to identity which device sent the 0 and which device sent the 1.

this concept is di.cult to be implemented in practice due to the strict requirement of perfect synchronization as well as amplitude and phase match.


In TinyECC, since almost all the modular operations are modulo the same prime number p, Barrett reduction can potentially speed up the computation.

this requires the implementation of a separate reduction algorithm, which implies larger code size (i.e., greater ROM requirement) on sensor nodes.


tercept the very function, by adding a hook, setting a debug break point or et al.

since the number of COM components and their interfaces is extremely large, writing callback functions for every method is too expensive.


As we discuss below, websites often serve localized and/or personalized content, making it non-trivial to form a consensus of a retrieved webpage even in the absence of an adversary.

by verifying content rather than certi.cate .ngerprints, Senser does not rely on SSL/TLS or the web s PKI and is thus compatible with sites that do not support HTTPS.


TIGHT KEY ENCAPSULATION FROM SELECTIVE-ID IBE It is easy to turn our CCA2-secure encryption system into a CCA2-secure Key Encapsulation Mechanism (KEM).

we can get a simpler construction with a tight security reduction if we take the lesser requirements of the KEM to our advantage and start from the Boneh-Boyen IBE [3].


Because we numerically calculate W (t), we cannot derive a closed-form expression for the distribution observedvic (k, t).

given values for noise parameters ., L, and Srate , we can instead numerically calculate it.


In this respect, our work is similar to generic methods described in a very recent concurrent and independent work by Freeman [13].

our schemes are di.erent from the work of [13].


[4] propose a scheme allowing multikeyword search with one encrypted query.

like [5] this scheme is not practical for large databases.


Since signatures are independent from each other, there are some efforts which compile several signatures together to exploit the parallelism of matching process using regular expression matching [6, 14, 15].

these approaches may introduce some connections to different signatures.


FromSpeculation toSecurity: Practical andEf.cientInformationFlow TrackingUsingSpeculativeHardware HaiboChen ,XiWu ,LiweiYuan ,BinyuZang ,Pen-chungYew , andFredericT.Chong§ ParallelProcessingInstitute,FudanUniversity Department ofComputerScience andEngineering,University ofMinnesota atTwin-Cities § Department ofComputerScience,UniversityofCalifornia atSantaBarbara Abstract Dynamicinformation .owtracking(alsoknownastaint tracking) is an appealing approach to combat various security attacks.

the performance of applications can severely degrade without hardware support for tracking taints.


Therebytheattackerisabletodeterminetheaddressofanarbitrary instruction inthis program image.

2.2.2 Partial Overwrite Attacks a partial overwrite attack does not even require disclosure of concrete address values.


Compatibility groups will decrease in size (and increase in number) if a finer grained classification is made (for instance, if sequences of two or more incoming characters are considered in defining the compatibility groups).

most of the NFA states have a single incoming transition, and we experimentally verified that a finer grained classification does not significantly affect the performance of our implementation.


[24] propose three new windowbased feedback algorithms for overload controls in a proxy, and compare them with existent algorithms.

none of these works have proposed a more ef.cient alternative to the use of digest authentication, even though it has been shown that it has a considerable impact on proxy s performance, specially if a remote database is used.


It could be argued that whenever a policy is satis.ed, the resource it protects must be disclosed.

such a requirement would impinge on the agent s autonomy in determining what to disclose, and would lead to a potential need-to-know attack in the other direction: a client could send all of its credentials and then wait to receive a list of resources for which it has satis.ed the policies.


This approach has many system challenges because of the real-time constraints of detection and subsequent jamming of packets.

this approach enables WiFire Copyright is held by the author/owner(s).


In the protect phase, an attempt is made to prevent an attack on the database.

absolute prevention can never be achieved and hence there is a detect phase.


Such an intersection approach might look similar to the approach presented in this paper.

wSPL considers neither rule E.ects nor XACML rules combination algorithms in the intersection process.


There exists certainly many di.erent classi.cation algorithms that are able to map multiple input features to multiple output classes, even for complex, non-linear mappings, such as Support Vector Machines, Arti.cial Neural Networks, etc.

we are confronted to speci.c constraints that do not allow us to use this type of supervised machine learning techniques.


If sufficiently motivated, say for signifi- cant financial gain, these members may be willing to sacrifice their personal information on a limited scale.

if serf-enforcement is incorporated into our system, even those willing to leak personal information to a few colluders might be affected by it in the following way.


If the execution path is detected, the adversary will have some con.dence that the detecting attacker instance is co-located with the victim.

this approach may have false positives, in which not-co-located instances were reported as co-located due to activities of other tenants sharing the same OS, and false negatives, in which co-located instances were not reported so.


Following [34], protocols secureinthepresence ofsemi-honest adversaries assume that parties faithfully follow all protocol speci.cations and do not misrepresent any information related to their inputs, e.g., size and content.

during or after protocol execution, any party might(passively) attempttoinferadditionalinformation about other party s input.


Better Web design can alleviate the problem.

due to the distributed and stateless nature of the Web, problems like cross-site scripting and the use of cookies may continue to cause problems.


It is possible to capture the case of several ASes colluding with de.nitions and a security lemma similar to that above.

the de.nitions are more complex and are omitted here.


For malware detection, it is used to mine the system call dependency graphs [12].

when such a system is deployed for analyzing new executables, searching for exact subgraphs could be a brittle approach LEAP will not identify malicious behavior if it does not correspond to a graph it has seen before (a slight change in the graph may be enough to avoid detection).


MOV ECX,200 XCHG EAX,ECX LOOP -1 Listing 1: SUB with LOOP instruction At .rst glance, this loop may seem entirely pointless, simply exchanging the values of EAX and ECX at every iteration and decreasing the value of ECX.

because ECX constantly witches between containing the actual loop counter and the value of EAX, the latter is actually decremented by the former until either of them reaches the value 0.


Their implementation requires 3322 bytes in ROM and 177 bytes in RAM.

to achieve low code size they have sacri.ced performance.


Additionally, users might need to report their location while they move from one location to another and, during the movement, their location information must be updated.

simply providing a new obfuscation region when the previous one is no longer valid, i.e.


This is similar to the common notion of second pre-image resistance of cryptographic hash functions.

due to the time-bound of the software attestation scheme it is su.cient that ChkN ful.lls only a much weaker form of second pre-image resistance since we need to consider only blind adversaries who (in contrast to the classical de.nition of second pre-image resistance) do not know the correct response rN to the veri.er s challenge (g0, r0).


Applying security validation at the appmarket level offers a great opportunity to enhance mobile app security.

app markets currently apply either limited manual validation or no validation at all.


Note that IH is permitted in AL because we interpret it as the execution of a high integrity .le within a low integrity subject.

(the term invoke-up is used in Biba model to refer to the execution of a high integrity subject.)


En-cryption and Unobservability provide protection of the commu- nication connection and, therefore, affect both communication partners equally.

a user can provide Authenti-cation and Acknowledgement of a call without the partner doing the same.


Temporal RBAC [5, 7], is related to our work in the sense that TRBAC models are concerned with the important notion of change.

in [5] and [7], the events of interest are time/clock events.


This is not surprising a similar observation has been made in other contexts in security, for example, testing for bugs in cryptographic implementations [2].

we do borrow ideas from software testing, for example, the small-scopes assumption which we discuss above.


We believe that the familiarity indications derived from the context should in the future be considered in combination with other features measuring also the trustworthiness of the devices in the user s proximity.

we do feel that the notion of context familiarity provides a valuable tool on the way towards implementing functionalities that could adapt security policies dynamically according to the relevant context in which a mobile device is in at a speci.c point in time.


The private key is activated through the use of a user PIN.

biometric mechanism can be used also with the PIN to increase the level of the security depending on the eservices.


Researchers have shown that capability systems may be used to prevent some of the vulnerabilities above, such as confused deputy vulnerabilities [28].

using a capability system presents a challenge to programmers because they must reason about both the functionality and security of their programs concurrently.


We note that despite a simple policy speci.cation syntax, Clouseau policies can quickly become large and di.cult to understand due to the number of constraints that might exist between elements of a credential chain or .elds of credentials in di.erent chains.

we do not view this as a limitation of Clouseau.


The number of veri.cations in Phase I becomes prohibitive very fast for JK: for an outer code distance of 24, 1596 veri.cations are necessary.

as the outer code storage overhead decreases from 32 to 16 in the new variant, the number of challenges increases at an almost linear rate.


8.1 On Key Sizes In the previous section, we showed the performance difference between our 128-bit PUF-based client-server architecture and various sizes of RSA keys.

comparing the security guarantees of our system with the use of PKI to distribute symmetric keysis somewhatchallenging.


The hospital may wish to share this information in order to receive payment from Bob s insurance company.

based on guidelines related to this sharing of medical records with third parties, the hospital may not wish to share Bob s entire medical history, as doing so could adversely a.ect Bob s continued coverage from his insurance company.


proliferating worms [34] or Trojans [23].

in situations where the real-time requirement is not critical, e.g.


The Panchenko classi.er relies primarily on packet sizes and is able to achieve good results.

our classi.er is able to achieve good results even if all packet size information is removed from the trace, as in the randomized cover tra.c experiment.


[25] extend Bucketisation to multi-dimensional data that enables range queries.

the Bucketisation technique is not scalable.


2.2 Problem De.nition Capability systems attempt to thwart DDoS attacks by prioritizing legitimate traf.c.

an attacker can also launch a DDoS attack on the request channel of the capability system.


As a result, facilities must be provided for the operating system to identify the owner of data, and the security hashes of memory data must be available to the operating system, so that it may relocate data.Finally, the decomposition of complex functions into simple primitives, as in the case of register saves and restores, allows the operating system to better control resource usage.In the case of XOM Key Table management, the act of allocating a resource can be privileged, and thus decoupled from the act of accessing the resource, which remains unprivileged.

our preliminary performance numbers look promising.The hardware overheads are not small with memory encryption and decryption costing 15 cycles and saving and restoring a protected register requiring 13 instructions instead of 2.these costs are only incurred when the machine must do an even more expensive operation either a memory fetch (which takes 150 cycles) or a trap into the kernel.


In fact, the session {r4, r7}is an optimal solution for the IDRM problem, and it is also a corresponding optimal solution in the weighted set cover problem.

the greedy algorithm only generates one optimal solution {r5 , r7}.


where q is true; consequently, RPATs do not care what the resulting states look like.

route seeks for a resulting state with expected assignments.


Handles are generated by incrementing a 61-bit counter, which is a storage channel.

since the kernel encrypts the counter value to produce handles, the user-visible sequence of handles does not convey exploitable information.


SAML provides a message exchange protocol for communicating attributes and credentials among different autonomous parties.

the protocol needs to be tied to authentication and authorization mechanisms to support secure information accessibility in the distributed collaborative environment.


Also, we design originator related roles and collaborator roles that are resource sharing speci.c, in order to re.ect the special characteristics of an originator as well as to accommodate an originator s collaborative sharing domain on the given resources.

as an extension to the traditional RBAC permission assignment, our framework allows the originator to delegate usage and dissemination capabilities through the capability-role assignment.


Thus in theory, and temporarily setting aside the problem of leaked information, the probability of guessing the location of a particular library (contained in the mapped regions) is 1 228 .

libraries are generally loaded in a static order and with static o.sets to each other.


This reduces the size of the log required for veri.cation when reading.

it still results in potentially unbounded and long waiting times for increments.


The author investigated the resilience of commonly known aggregation functions and found that the average, the minimum and the maximum calculations are not resilient even against only one compromised node.

the median was found to be resilient, the count to be acceptable and the trimmed average to be employable in some cases, namely when an upper bound on the percentage of compromised nodes is known.


When a new SP is created, the Pro.leRegister stores the SPde.nition in thePro.leStore and it also registersthe context expressions associated withtheSPintheContextExpressionDB.In this way, the newSP canbe activatedif the Context Detector evaluates to true the context expressions associated with it.

in MOSES, each SP has assigned an owner that is the entity authorised tode.ne and modify theSP.The owner of an SP canbe the user of thedevice that createsher ownSP.a user can deploy on her device SPs de.ned by third-parties.


If a node is compromised, only messages to and from that node are compromised.

the use of pairwise keys requires much more overhead than simply using a network key; each node has (n-1) keys versus a single network key.


RELATED WORK Computer viruses have been plaguing the Internet for many years, and a number of detection and defense mechanisms have been proposed [29, 30, 35, 38].

only recently have the smartphone viruses attracted much attention in the research community.


Using only English-compatible ASCII characters, the increment instruction inc is the most obvious candidate for increasing a register s value.

this one-byte instruction will only increase the value of a register in increments of one, yielding no space for the decoder.


If it is currently 10am, then this rule explicitly denies the execution of gaming application.

if the current time is 1am, this rule implicitly allows the execution of gaming applications.


We notice that Momo and Wechat provide an option to manually remove their locations from the public.

with no idea about the potential risks brought by LBSN apps, few people do choose this option.


If a type-matching catch is not found, the stack unwinding should be resumed.

if there is a clean-up routine that is used to deallocate objects allocated in try statements, then the clean-up routine needs to execute before the unwinding continues.


Since J would thus use three blockcipher calls per message block, one might naively expect a 50% slowdown.

eME computes various o.sets that are addedto theblockcipherinputs and outputs, and these computations are quite costly, so our simple ECB pass is less expensive compared to EME than one might imagine.


Apps should be allowed to access the system resources, as well as each other s resources.

such accesses should be controlled, not arbitrary.


6.2.3 Sub-stroke Selection at Appropriate Resolutions So far we have assumed that all sub-strokes segmented from a stroke have the same time duration.

in reality, people have consistent and distinguishing behavior for sub-strokes of di.erent time durations.


Although TCP cookies are ine.ective in that scenario, client puzzles can mitigate the e.ects of such an attack by an adversary that is CPU-limited.

in recent years attackers have demonstrated their ability to e.ectively utilize large numbers of subverted hosts in their attacks [25].


For instance, attackers can exploit client-side vulnerabilities to leak sensitive emails to remote adversaries.

1Gmail does not include external libraries and does not mix content from HTTP sites; nevertheless, several other web applications we study in Section 4 include external libraries and mixed content, which poses serious threat to sensitive information.


However, a content distributer might actually want to scale the number of servers based on the expected number of hosts.

our main proofs are valid even when P is a function of N. the scaling laws would look di.erent.


Text-based CAPTCHAs, in which users are required to transcribe text presented in a distorted image, make up the majority of CAPTCHA systems in real-world use.

their vulnerability to attack has been repeatedly demonstrated by computer vision researchers [5, 15, 17].


Our approach uses action s state to approximate related actions: actions that use the same state are related.

in order to split a component that contains related actions used by violating tasks, we require extra information to be present in the architectural description: read/write on the action s parameters.


(If a hash function produces n-bit digests, then one can surely obtain a collision by applying the hash function to 2n + 1 distinct inputs; and one can obtain a collision with high probability by applying the hash function to 2n/2 inputs.)

suppose that M1,M1 are such that 0nt starting from IV and T1 = T2 = , they produce the same value for C(1) but not necessarily the same value for (1) (1) (1) (1) (1) (1) T1 ,T 2 , i.e., (T1 ,T 2 ) = ((T1 ) , (T2 ) ).


Fingerprint captured by mobile camera is an alternative for identity authentication to control the access to the mobile device.

the touch-less .ngerprint needs to be captured under strictly controlled environment because only front view .nger image presents useful minutiae information.


Ideally, one would want the privileges to be diserete and the acquisition process be independant because that will gauarntee an increase in attacker's risk and cost.

this ideal goal can only be reached partially as explained be- low.


Malware could use this to verify/authenticate our incorrect probing packets and refuse providing any future response.

even in this worst case, we argue that this kind of noresponse isindeed aspecial,suspicious,recognizable response that could be used in MCB probing.


Their strategy o.ered an alternative way to detect the propagation activities of an Internet worm.

both of these approaches rely on the characteristics exhibited in worms scanning tra.c.


Voice Session: For the voice session we consider a similar set of features and we generate the labels in a similar way for number of outgoing destinations, day time shift and the list of base stations.

for the voice session we take into account the duration of the voice calls and we generate the label low if the voice call has zero duration and high otherwise.


For simplicity of presentation we assume that the circuit always outputs a single bit and that the result is computed by the last gate in the list.

more complex scenarios with multiple output bits can be implemented with ease as well.


Libverify is an enhancement of Libsafe, implementing return address veri.cation similar to StackShield.

since this is a library it does not require recompilation of the software.


A breach of security occurs when a stated organizational policy or legal requirement regarding information security, has been contravened.

every incident which suggests that the confidentiality, integrity and availability of the information has been inappropriately changed, can be considered a security vulnerability [4].DoS attacks were theorized years ago, before the mass adoption of current Internet protocols [5][6].


When encrypted keys are already in hand, the directory read would no longer be found in the track bu.er, and would have to go to disk.

this time would be overlapped with key acquisition, reducing total overheads.


After splitting, the original code and the secret sharing code are interleaved during execution, achieving certain level of parallelism.

in this way the function call overhead is increased, since one function call becomes two or more.


On one hand, this fosters the development of a new kind of Location-Based Services, where people can now, for example, enquire for the location of a mobile subscriber directly over the Internet [13].

this raises signi.cant privacy issues regarding who can access this location information, how it will be used and how long it will be stored [12].


The client side aspect of the problem has been typically handled assuming a symmetric approach (based on access control rules) for regulating the release of user private information, and possibly enabling the client to engage in negotiation with the server.

access control-like speci.cations do not completely .t the possible protection requirements at the client side, where users need approaches to express in an intuitive and easy to use way their natural perception of the privacy value of their information.


The Java imple 3Of course, browsers also use cryptographic functions as part of the TLS protocol.

it is impossible for web pages or web apps to access this functionality except for securing TLS tra.c.


This code implements the actions that the sensor is required to perform (for example, collecting and aggregating data).

there are many situations where this code needs to be updated or changed after deployment.


As long as process i has not finished its task, we say that the process is ready to run on the server.

since the server is multi-threaded, at most one of the ready processes is running on the server at a given time.


In practice, Alice and Bob would probably notice the presence of a third person during key agreement, and look for another place where eavesdroppers cannot approach them.

in some situations such countermeasures may not be practical.


Securing the ring As a mobile guest shares a secret with its escort, a naive solution is to use the secret as cipher key to encrypt the source and destination MAC addresses in 802.11 packet header.

this naive solution has a non-trivial problem.


The architecture extensions are mapped into the MAPE reference model.

the extension parts are needed and applicable in other adaptation models also.


These studies have helped guide research over the past 20 years.

a large-scale .eld study permits the measurement of users security and privacy challenges and behaviors with much greater ecological validity than in the lab, where the experimental setting might not re.ect users actual behavior in their natural environment [4].


One thing to note is that in .gure 6, a virus can quickly infect the entire smartphone population in less than 3 hours, based on the mobility pattern in [36].

the proxy can always catch the infection attempt (P(detection) = 1.0), our proposed solution can limit the number of infected users to 222, which is only 0.222% of the population.


applying security patches, and they can only be discovered by attestations.

in our experiment, we do not di.erentiate the trustworthiness of a state, as our main purpose is to evaluate how the changes in state are discovered.


For example, in case of the compromise of a reader, all the tags that share a pair-wise key with the untrustworthy reader need to be updated with the new keys securely, hence incurring prohibitive overhead for key renewal.

there is no secret key shared between the claimer and the verifier when using digital signatures.


Based on the Nyquist frequency, a camera that captures X frames per second is limited to X/2 bits per second when using an on/off encoding scheme.1 We could add multiple LEDs to encode more bits per frame.

the user would have to pay careful attention to how the laptop is positioned within a trusted location to ensure the LEDs are easily differentiable so the laptop can successfully decode m. Instead, we design key derivation protocols which are 1TheLEDon is a 1.


that use self-certifying IDs as public keys [1, 23, 24, 34] as assumed in ICING.

such mechanisms have issues with key revocations.


In contrast to existing work, the rated entities can control whether their reputation is revealed to a third party.

if an aggregated rating is revealed, our system ensures its integrity.


6.1 Stolen phone tracing and self-destruction Recently, lawmakers in California have approved a bill, which requires all smart phones sold in the state to have anti-theft software installed, so that once the device being lost or stolen, it cannot be used any more, even after a hard reset [16].

in order to achieve that goal, the .rst step is to uniquely identify a device.


We found that prompting users for their user name and password for every RP sign-in attempt could enhance their security perceptions.

doing so increases the number of times users need to enter their credentials, which might be annoying for some.


Consequently, compared to signal strength and carrier sensing time, PDR is a powerful statistic in that it can be used to di.erentiate a jamming attack from a congested network scenario, for di.erent jammer models.

it still cannot di.erentiate the jamming attack from other network dynamics that can disrupt the communication between the sender and the receiver.


As mentioned above, a malicious server may cause some blocks not to get garbage collected by omitting replication noti.cations, but this has no impact on security or durability.

the malicious server cannot cause blocks to be garbage collect blocks before their time, which if it could, would undermine the durability of the data.


An encrypted drive whose encryption cannot be broken is just data.

with the proper insight (i.e., the decryption key), the data can become valuable information.


That is, two sessions with adversary interference under a cross-message attack [25] are de.ned to be matching.

from our view, in light of the cross-message attack [25](that causes role confusion between two matching sessions for role-independent IA-DHKE), such a de.nition of matching sessions is ill , as it does not well capture the intuition of intended communication partners without adversary interference.We notice that, for robust (H)MQV and KEA that are role-dependent as ( B) are involved in a .xed order in session-key deriva- A, tion, the more natural de.nition of matching sessions, where the two players are required to have matching roles,is used ACMIMadversary controls all the communication A channels among concurrent session runs of the KE protocol.


These recommendations may serve as credentials asserting recommenders trust in certain attributes or properties of the recommended users.

the trustworthiness of the recommenders may vary depending on the relationship of the recommenders with the service provider [4, 5].


TiRi .-------------- Clock: Stop, output .t Check Ti and .t = tmax Figure 3: The Reid et al.

protocol this attack is not extendable to arbitrary symmetric encryption schemes.


Second generation broadband wireless networks are considered to be enterprise-level networks providing more capacity and coverage than first generation home- and small business-based WLANs.

security remains the most critical area of concern in both first generation and second generation WLANs.


Solutions such as coalition-based access control (CBAC) [11], Liberty Alliance Project [37], and Shibboleth [32] (based on SAML [50]) are examples of federated identity systems.

these solutions require pre-  Figure 2: How OpenID works.


A crafted 2D barcode that conforms to multiple standards (or an embedded barcode inside another) would be undetectable to an untrained human viewer.

decoding software usually employs multiple computationally cheap .nders for speci.c symbologies, e.g.


The output of this analysis is a set of program locations where mediation is necessary.

placing hooks at all these locations may be sub-optimal, both in terms of the number of hooks placed (e.g., a large number of hooks complicates code maintenance and understanding) and the number of authorization queries generated at runtime.


Predictive mitigation can address even dif.cult lowlevel timing channels such as those createdby hardware contention at the level of the processor or the bus, as long as the mitigator isabletodelayexternally visibleeventsto preciselythetimepredictedby the schedule.

the very generality of predictive mitigation can make the leakage bounds conservative, and performance of the system is then hurt because the mitigator excessively delays the release of events.


Further examination showed that since our PC microphone includes noise cancelation algorithm, the vibrations were hard to detect in recordings taken from 4 ft away and farther (as the vibrations were regarded as noise by the microphone).

when investigating the IMD eavesdropping, we were able to utilize a parabolic microphone to distinguish between recordings of the piezo beep taken from a distance of 12 ft away.


The size of the dots is larger than the theoretically smallest dots the printer can print (in this case 1/600 inch for a 600 dpi printer), so that the dots are clearly visible after printing.

the dots are enough small for the random misplacement of toner powder to be signi.cantly noticeable around their boundaries.


For instance, an access control policy can state that the only OSN participants authorized to access a given resource are those with a direct or indirect friendship relationship with the resource owner, provided that this relationship has a given trust value.

the access control policies supported by the proposed framework have some notable improvements w.r.t.


OpenID and CardSpace focus on allowing users to consolidate and manage their digital identities and don t o.er users anonymity from relying parties.

opaak s main goal is to provideusersanonymity fromrelyingparties(aswellas the identity providers) while simultaneously preventing spam and Sybil attacks.


The availability of full genome sequencing will soon allow performing more ef.cient computational analogs of tests that are now conducted exclusively in labs.

privacy issues must be taken into account by both users and testing companies.


As in the previous section, passing a directory endpoint to a peer process might allow the peer to perform certain directory operations (enumeration, for example) without additional authority.

opening a new directory endpoint requires an additional access check at the file system.


Consider the example in Figure 2 from Line 15 to 18 of P 1,in which min(a, b, c) is computed by .rst comparing a and b to .nd the smaller one and then comparing it with c. These operations are embedded in the loop from Line 2 and 7.

an interesting observation is that if c is tainted, the .rst iteration of the loop only taints the statement at Line 17 and array D. the next iteration sees the statement at Line 16 also become tainted because this time, D is tainted.


We introduce the new security notion of randomized queries veri.ed by the BSSE scheme.

the label that we associate with each encrypted document can be seen as the secure index de.ned by Goh [13] or the secure scrambled array de.ned by Curtmola et al.


We focus on bit.ly URLs since bit.ly offers an API [6] for querying the number of clicks received by every bit.ly link; thus our estimate of the number of clicks received by every application is strictly a lower bound.

each bit.ly link that we consider here could potentially also have received clicks from other sources on web (i.e., outside Facebook); thus, for every bit.ly URL, the total number of clicks it received is an upper bound on the number clicks received via Facebook.


Eve satisfes Eve 1, projectManager, so the authorization system permits her to perform the action.

the new obligation,(Alice, test, (software), [01/01/2010, 02/01/2010]), would make the system unaccountable, since Alice does not have the role of black-box tester.


One may argue that the policy 1o only captures Chinese Wall for a single object (o), whereas the real Chinese Wall policy is a single policy stating that for every object o, the simple security rule applies.


[14] showed that selective encryption is sound and demonstrated its relation to Shannon s work.

in practice a bitstream is not always redundancy free, as required by Shannon.


Upon detection of a malicious software on any one of these three hosts, one can proactively quarantine the other two nodes without affecting messaging in the other clusters.

if one quarantines the cluster with nodes (denoted in black circles) completely from the rest of the network, the total cost of quarantine will be the sum of messages exchanged along overlapping edges e3,5, e4,13 , e7,13 , e13,15 , and e5,14 .


Consistent with the exploratory study, participants Figure 9: Screen size makes it hard to use (1 = +ve) felt that DAS is harder to use with a small screen.

the size of the screen did not affect the participants perception of TMD.


The concept of role is associated with the notion of functional roles in an organization and hence RBAC models provide intuitive support for expressing organizational access control policies.

the size and complexity of typical organizational policies make it di.cult to ensure their consistency.


The RSU can verify a large number of signatures as a batch using three pairing operations (see works like [13] and [6] for what a pairing operation is).

their work relies heavily on a tamper-proof hardware device, installed in each vehicle, which preloads the system-wide secret key.


We note in passing that there exist low-cost (relying on symmetric key techniques) anonymous authentication protocols in the literature, for example Song and Mitchell s RFID protocol [50], that may be adopted to address our privacy concern.

using such a solution provides only partial privacy protection because of the fundamental limitations of a symmetric key approach [30, 45].


They also showed that their method can be applied to other push-button devices such as telephone and ATM pads.

the reliance on tagged samples signi.cantly limits the scope of the attack.


We considered the assignments of users to roles and the assignments of permissions to roles as administrative issues, thus, were not included in this study.

as part of our future work, we intend to address delegation issues, which we believe play an important role in multicast communications.


The worm author s freedom from litigation and imprisonment rests on his ability to hide his identity.

because the validity of the access tickets he sells can only be determined after the sale, the price he may charge depends on his reputation.


Also, there is a ±20% speed di.erence between a bimodal branch predictor and a 2-level adaptive predictor.

these parameters are typically not con.gurable in practice and thus they are not discussed further.


Encryption algorithms have often been proposed as a solution to cope with this issue [6 8].

their energy-e.ectiveness is questionable due to their intrinsic computational complexity.


The resulting system would not provide the same level of fault containment, leading to an increased e.ort for safety certi.cation.

this point illustrates that the virtualization approach is not limited to systems with average or low IRQ rates.


That is, the target kernel is executing in protected mode, with a set of paging structures mapping linear addresses to physical addresses.

the attacker s device addresses physical memory.


For example, from Example 1, it may appear, at .rst sight, that Dave s lack of authorization, as a consequence of his blacklisting, is inconsistent with Bob s intention to sell to Dave.

it should be clear here that the speci.c information about Dave s lack of authorization overrides the general intention that Bob has to supply bangles.


The rule [Opt] corresponds to optimistic sampling, which allows substituting e. rby r 1Probability tags increase the readability of rules and support a more uniform interpretation of judgments.

they are super.uous and can be deduced from the shape of the event: for every valid judgment Fp c * : f, the probability tag pis 1/2 i. f= Guess.


The authors relate observational equivalence to random variables and use Shannon entropy to quantify the information .ow.

their measure captures the information gain of a passive observer instead of an active attacker: the public input to the system is chosen 2The computation of <8(2) for .nite-.eld exponentiation took 40 minutes on a 2.4 GHz machine with 3 gigabytes of RAM.


This synchronization can be achieved synchronizing each sensor node to a common reference time.

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


In addition to that, Merkle trees are used for integrity veri.cation and protection of the root value relying on T P M functionality.

the poor description of storing/sealing the root value of the Merkle tree hash, raises doubts about protocol s validity.


Collaboration and evolution capabilities of the DE can be utilized to process patient data aiming at the aforementioned goals.

the stakeholders approved to be part of the DE should be strictly regulated.


INTRODUCTION eb services promise a new era of fexibility and power for web applications.

this power also promises security challenges for web service providers, especially regarding access control, a.k.a.


Another important factor is that certi.cates become immediately usable after initial registration.

tACK, and P/C/CC do not support this feature.