Others deal with the integration of the Role Base Access Control model in distributed systems.

all these studies deal with the protection of the system and none studies the impact of such mechanisms on the operating system performances.


What is surprising though is the importance of Operating System security settings in preventing DoS.

it is not surprising anymore when one analyzes the security settings of Solaris 9 in detail; it does provide TCP and ARP settings that are effective in preventing DoS.


Indeed, an enforcement state could be exactly the corresponding authorization state.

that would not correspond to an ef.cient enforcement mechanism.


So, the local detectors have access to only one pixel at a time to make a decision.

if the local detectors have access to more pixels/coefficients that carry the watermark the ease with which we can detect watermarks increases.


Ideally a WebView app should only require the INTERNET permission.

we found that nearly all of the identi.ed WebView apps (.93%) required more permissions.


... Now, aprocessx can Read an object yonlyifthedynamiclabel of x is DSLeq (less than or equal to) the static label of y. Conversely, x can Write y only if the dynamic label of x is DSGeq (greater than or equal to)the static label of y.

x can Execute y only if its own IL is lowered to or below the static label of y.


Another approach, in a network of size n, is storing n - 1 pairwise keys in every node, each for communicating with one other node in the network.

in a typical sensor network with thousands of sensor nodes, the storage requirement for this approach is beyond the memory limitations of sensors.


sSO sometimes requires unnecessary work when a simple authentication mechanism between two parties is required.


An educational software system provides the capability to display question s solution.

a solution could be revealed to a student only if the student previously tried at least two times to answer the question.


This is recommended in general Linux systems, and can be achieved using a script activated during system startups and shutdowns.

this countermeasure appears to be absent in Android.


For example, if a permission request was granted for an application, the permission will be revoked once that user logs out.

dR BACA also allows a single user to log into di.erent devices, as long as they are part of the same overall security policy.


Whenever a word is read from a code page, the destination is also marked as constant.

even if two constants are used as an input of an operation, we do not mark the result as a constant.


Although DDOS attacks using embedded devices have certainly been carried out on a relatively large scale, most of the other attacks described in this section have not.

considering the data presented in Section 5, we posit that it is only a matter of time before such attacks are carried out systematically on a large scale.


Server and client side script plays an important role in providing better experience to web users.

malicious users/attackers use these functionalities to build attack vectors that directly or indirectly attack these web users.


Dependency graph samples and obtained clusters To avoid tracking the information flows with a low risk of propagating malware programs, the rules do not trace most reading operations on files, directories and registry entries, which are frequently invoked but difficult to propagate malware programs.

subtle malware programs might evade tracing by changing registry entries or configuration files which subsequently affect the processes reading them, so as to run malicious executables, escalate privileges, impose damages on system, etc.


Anonymous credential schemes are the optimal realization of usercentricity.

on inexpensive hardware platforms, typically used for eID cards, these schemes could not be made to meet the necessary requirements such as futureproof key lengths and transaction times on the order of 10 seconds.


For instance, recent browser designs have signi.cantly improved privilege separation between code components [4, 5, 16, 21, 25, 33, 46, 63, 69].

these techniques do not directly allow web applications to enforce control on their data; a compromised component with access to sensitive data can still launder it through its export interfaces.


One possible approach is to give developers an option to supply information such as one location per hour and two data backups per day in the application manifest.

this approach relies on developers voluntarily requesting for the minimum privilege, which has shown to be challenging [8].


For a realquerywith mode= ADD , the candidatequery will assign mode= aaa which, being an invalid mode, may actually cause the program to throw an exception.

the test for mode is done on the real string and hence the candidate query will be an INSERT-query with appropriate values of the candidate input substituted for the real input in the query.


We cannot do justice to the entire litera ture, as there are lot of them.

we have covered a few to show the spectrum of work in this area.


One might ask if the challengeresponse could have been replaced by an authenticated IBE scheme.

currently such schemes does not provide message origin authentication or entity authentication per see.


For example, most programmers look for a bu.er over.ow when the problem statement is a strcpy.

to provide more vulnerability information, MemSherlock incorporates the taint analysis from TaintCheck [20] to check if the value written to the destination address during the corruption is tainted.


By increasing k, we can make the ratio ./(tsh + tch) arbitrarily close to ./tsh (which is the best we can hope for).

we pay for this increase by also increasing the computation time for the honest veri.er; thus as k gets larger, the time-gap for the puzzle (the di.erence between the work done by the honest solver and the honest veri.er) becomes smaller.


The result of this examination shows that the OMA DRM v2.0 standard is a suitable basis for a privacy-respecting DRM system.

the actual deployment of a complete DRM system for digital content based on OMA DRM v2.0, containing e.g.


Other work explores running end-host replicas (dubbed virtual smartphones or clones) in the cloud to enable more powerful analysis [15, 25].

these approaches still rely on detecting malicious or abnormal behavior after apps have been installed and run on individual smartphones.


The cloud provider can o.er both higher bandwidth and availability.

if the cloud provider is also trusted not to collude with Bob, Alice could avoid bulk transfer and selectively fetch only desired ciphertexts.


If a web service or web method is mapped to no request policy, WSE will drop all messages sent to it.

if it has an empty request policy () attached to it, then all messages sent to it will be sent through unchecked.


between secret availability and vulnerability, we believe that splitting up secrets across multiple servers to enhance security is a seminal idea.

the user still has to trust a single party that hosts the servers.


To support a limited encrypted search capability, the policy engine tags records with attributes that describe the data and can encrypt those records using key-policy ABE.

we do not consider sensitive attributes that may leak information about the underlying data.


The authors state their assumption that the token is protected against overclocking and that the RF carrier operates within the ±7 kHz tolerance speci.ed by the relevant standard.

this requirement does not seem to be enforced by tokens currently available.


We could use two operators, one for each meaning, and allow them to be applied to non-unit terms.

this adds complexity to the algebra and we have not seen the need for this.


A vast amount of research is available for each common type of security mechanism, including design and evaluation criteria.

the classi.er point of view might be helpful when considering a security system, the multitude of security mechanisms built into a system to ful.ll its security objectives.


Results of the analysis of identity protection audio information Scrambling Individual 1 ..11K ..12K ..13K Classical 0,749 0,754 0,759 Virtual 0,812 0,801 0,798 Adaptive virtual 0,992 0,995 0,981 Scrambling Individual 2 K..21 K..22 K..23 Classical 0,372 0,361 0,369 Virtual 0,561 0,564 0,57 Adaptive virtual 0,612 0,601 0,609 Scrambling Individual 3 ..31K ..32K ..33K Classical 0,698 0,699 0,691 Virtual 0,891 0,889 0,894 Adaptive virtual 0,949 0,941 0,953 These results confirm the dependence of the open processes of scrambling from the individual characteristics of the sources of speech information.

as shown in table 6, these features can significantly affect the quality of information security (individual 2).


The Branch-Cluster A contains the Wmiprvse.exe process and its descendents, which is known as Windows Management Instrumentation and thus benign.

the Branch-Cluster B was recognized as malicious because it showed two malicious behaviors: abnormally creating the process cmd.exe and modifying registry for auto-startup.


For each individual phone, the offset data access location.

refresh REGISTER .ngerprinting technique depends upon the packet s arrival time as recorded by the DI module, and hence depends upon the network path characteristics.


Clearly, moving to 64-bit platform or using more .ne-grain randomization will minimize the chance of such attacks.

the goal of our system is precisely to defeat such attacks.


Although this is weaker than Bayes Nash incentive compatibility, when expected utility is used, the restriction of Inequality (1) says that, taking the expectation over the potential violator s private type, there is no incentive to commit the violation.

this potential violator will know his own private type before he decides whether to commit the violation; certain principals will have an incentive to commit the violation.2 In the second example (Example 3), we use a ranking function to determine which utility functions are the most typical.


[18] haveshownthatthese.lterscancatch many attack variants.

attackers can bypass these .lters by generating exploits that follow a di.erent execution path.


The output bitstrings are tags in V, typically of limited length, and the inputs may be bitstrings of arbitrary length.

in the case of map1, each tag immediately follows the message body it is meant to validate.


Students have a more positive experience, and LBIS staff can concentrate their efforts on less repetitive tasks.

those students who have trouble are more likely to be experiencing more complex problems with hardware or software.


In other words, if an object is corrupted by some noise with level less than sr, then with high probability, the detector should declare that the object is authentic if it is robust.

if the object is corrupted by some noise with level more than ss, then the detector should be sensitive enough to declare that it is not authentic, with very high probability.


Theadditionofablind signature service (BSS) gives PseudoID users transactional privacy.

identity providers can still log the relyingpartiesusersare visiting sinceusers(althoughitdoesn t know which user) are still redirected by relying parties to identity providers.


One straightforward way to deal with procedures is to inline procedure code and analyze the resulting program.

this leads to a highly inef.cient analysis that will not scale to large programs.


at point (Diane s o.ce, 14:00), Bob can activate the role (Admin sta.)


Then e the query Q veri.es only if ( s0 - s 0) + i=1( ci - c i)ai = 0, which holds only if a - as = 0 due to (h).

if A knows a, it would be able to .nd a non-zero tuple (¯s0 -s 0, c¯1 -c 1, .


Although there were less clients infected by SoBig in our network, the total volume of .ows generated 15000  by its infected clients was 50% greater than MyDoom s. Our data suggests that tra.c analysis on the mail server would be ine.ective against MyDoom, since mail server tra.c during the MyDoom outbreak does not appear to be distinctively unusual.

for Sobig, it is possible that one can detect its presence due to the large volume increase in 10000 the SMTP .ows.


All our experiments were conducted with Firefox.

it is important to notice that our implementation of ClickMiner is based on Selenium-WebDriver [4], which in turn is compatible with most major browsers, including some mobile versions.


A personal opinion is arguably hard to forget.

there is a possibility that opinion-based personal questions may be vulnerable to random guessing attacks.


An OT can overhear, intercept, and inject messages on the wireless network.

when outside of a trusted location, an attacker is unable to access the location s constrained channel [14] (e.g., infrared signals that are unable to pass through walls or sounds in an insulated room).


In principle the system must have had a vulnerability somewhere, and the attacker may be able toreinfect the systempost-veri.cation.

itis not easy to correlate infected .rmware in one device with a vulnerability in that device s expected .rmware, e.g., the vulnerability may have been in the OS and the driver that updates device .rmware may have been compromised.


There have been many news items, discussions, and blog postings on the topic.

it is currently unclear to what extent clickjacking is being used byattackersinthewild, andhowsigni.canttheattackisfor the security of Internet users.


The response by eHarmony was similar to that of LinkedIn, where they decommissioned the affected accounts and informed the users via a post on their site and via direct email about being compromised.

unlike LinkedIn, some security pundits like Graham Cluley from Sophos, chided eHarmony for not using this as an opportunity to explicitly inform its members to change their passwords on other websites where they use the same password.


Violation of obligations may not be avoidable.

once an obligation is violated, the system should be able to clearly identify who is responsible.


Conversely, the awkwardness of programming web applications has motivated a second line of work toward a single, uniform language for writing distributed web applications [9, 4, 21, 30, 29].

this work largely ignores security; while the programmer controlscode placement, nothing ensures the placement is secure.


If the byte order of the host is di.erent to the one used for the TPM, a byte conversion has to be performed.

there is no conversion required for the proposed architecture.


Conclusion Pervasive environments mean the automatic system so that manage everywhere the convenient life to the users.

it requires the system that processes the task work instead of the users.


decl(UnivId), decl(Name, Dept) (11) Figure 5: University Library WS Access and Release Policies messages [8], entire XML documents [1, 9], tasks [17] and DRM [27], possibly coupled by sophisticated policy combination algorithms.

they have mostly remained within the classical framework.


to calculate the integral of the aggregated consequence function, one would expect that both centroid and bisection result in a longer response time.

all defuzzi.cation methods show a similar performance.


the organization enjoys many nice features of cloud computing, such as agility, reliability, scalability, cost e.ectiveness, easy maintenance, and so forth.

the downside is that,as many security criticshavealreadypointed out,there are potential privacy risks for the outsourced data.


Some techniques [6] detect attempts to corrupt the RA at the expense of little performance loss.

the protection they o.er does not extend to other data on stack.


Torealizeprivacy-preserving computation of J(A,B), we only need secure computation of |AnB|, since J(A,B)= |AnB|/(|A|+ |B|-|AnB|), andthis canbedone usingPSI-CA(seeSection 2.3).

when two parties compute the Jaccard index, with or without privacy, they incur computation and communication complexity(at least)linear in the size of their sets.


Unfortunately, administrators of sHype who apply the Chinese Wall policy to their domains must recognize and specify domains that may communicate via a covert channel.

recognizing covertly communicating domains is not straightforward in the threat scenario described in Section 3.1.


The method proposed in [30] creates thumb-prints of connections using packet content which can be compared to determine whether two connections contain the same text and are therefore likely to be part of the same connection chain.

the method fails when the connections are encrypted.


Finding suitable and secure proxy resignature schemes required a substantial e.ort.Natural extensions of several standard signatures were susceptible to the sort of problems above.To illustrate the intuition behind this, consider a naive proxy re-signature construction based on the popular Schnorr [23] signature.Let || denote concatenation.Recall Schnorr signatures with key pairs of the form (pkA,skA)=(g a ,a) and signatures of the form (r,s)=(g k,aH(m||r)+ k).One might think to give the proxy rkA.B =(b- a), so that it can re-sign messages as (r .

,s )=(r,s + rkA.B H(m||r)).as in the BBS scheme, anyone can compute rkA.B =(s .


Therefore, when studying mobile privacy, an experience sampling questionnaire can only ask for a minimal amount of feedback making sure that it can be provided in the shortest possible time.

in order to be useful, that feedback needs to be detailed, providing information about specific episodes and the contexts in which they take (or took) place [19].


An attacker may also introduce malicious software (either user-mode or kernel-mode) to compromise the production VM.

we assume the presence of a trusted hypervisor [25, 40], which properly enforces the isolation between running VMs.


When a LKM is compiled, a module-speci.c return address table will be initialized.

instead of being populated with the absolute memory addresses, the module-speci.c return address table contains only the offset from the module base address.


Since the private key (or symmetric key) is only known to the legitimate and registered entities, it is computationally infeasible for an outsider to forge signatures (or MACs) in order to impersonate legitimate entities.

an adversary may register many legitimate users and hosts as discussed in Section 4.3.


Although the event is localized, it is reasonable to assume that it will become visible to all the users to other levels in the hierarchy, say in the whole .oor or in the whole building.

thus, on the one hand, we have a spatial hierarchy that maps a physical location p into a set of logical locations, P toL(p), containing p. every localized event ev, generated in a physical location p is associated with a set of logical locations in which it should be visible, i.e., EV isible(ev).


In Figure 4, LUTs are connected in such a way that all the outputs feed into the inputs of the next level.

this is not a mandatory requirement for the digital PUF.


Their work supports our notion that standard clustering techniques can assist users in placing friends into groups analogous with privacy intentions.


This has lead to alternate approaches, such as discernibility [8] / l-diversity [12].

it is still dif.cult to answer the question, is the data anonymous enough?


In other words, st may possibly transit into a future state where a subject cannot ful.ll its obligation, which however is not due to any sub ject s negligence.


This has made hardware backdoors less generic and less attractive than more traditional operating-system backdoors.

the hard-drive market has now shrunk to only three major manufacturers, with Seagate and Western Digital accounting for almost 90% of all drives manufactured [4].


Unfortunately, management agencies often assume that insiders are trustworthy, and only worry about outsider attacks.

iT security solutions traditionally deal with prevention mechanisms such as authentication, access control, software security; detection mechanisms such as intrusion detection and malware .ltering as well as resilient architectures such as separation of duty [9].


Hence, the security features provided by Android are insu.cient to enforce the security policies required to protect sensitive healthcare information.

once we add our mechanisms to the Android operating system, such policies can be enforced.


This approach avoids having to re-key every user who shares access to a cell with the revoked user: Only if they share a key is there a need for re-keying.

in some environments, re-keying even a single user is expensive (or is simply not possible).


Consequently, in order to provide e.ective resource management, it is inevitable to adopt various cryptographic capabilities for managing resources in RBAC systems.

the existing cryptographic schemes have several limitations to address abovementioned features since those schemes cannot accommodate access control features of RBAC.


A user can trust an application if it is less risky than her trusted ones.

an application that is signi.cantly risky can also draw a user s attention.


The use of public key cryptography can mitigate this problem by providing a separate non-secret key for use specifically when encrypting data (this key cannot be used to decrypt the data).

data recovery still requires access to the secret decryption key, which must be conveyed from a secure location and used by a responsible party.


60% to incoming phishing e-mail  its recent version is better than the older one.

we also see that the rate of false negatives increases in the newer data sets for both versions of SpamAssassin.


For botnets of the sizes just mentioned (and for the small number of even larger ones [18, 19, 43]), speak-up-defended sites need a large clientele or vast over-provisioning to fully withstand attack.

we think that future botnets will be smaller.


One called Foo-Read would contain members who should have only read access to Foorelated documents, and one called Foo-full whose members should have full control (write and manage access) to those same documents, making it clear how those groups should be used in acces control lists.

our sample of DocuShare groups were much less organized.


Later, several top-down approaches have been proposed [6, 1, 12, 14, 15, 11, 5, 8, 2].

the bottom-up approach utilizes the existing permission assignments to formulate roles.


Notice that the .nal value of match depends on con.dential and secret data therefore the program is not secure from the point of view of non-interference property.

the program needs to inform to the user the result of the password checking process.


A TCG-based attestation for an entire component may be the strictest way to verify its integrity.

if the TCG-based attestation is demanded by all of the components, only some of the components that can participate in the domains, because the attestation strength that each domain calls for is different according to its usage scenario, so the strictest method is not always needed for all of the scenarios.


With the traditional PKI-based [1] digital signature schemes like RSA [2] and ElGamal [3], the public key certificate is used; this is issued and maintained by one or more trusted entities named as Certificate Authorities (CAs), which helps to DXWKHQWLFDWH WKH XVHU¶V SXEOLF NH with its owner.

the PKI-based system needs to execute lots of computation and huge storage space to manage the public keys and the certificates.


First, simple fuzz-testing tools such as the Monkey tool are not guaranteed to produce sufcient behavioral coverage.

our experiments show that this simple tool works .ne for the apps tested in our experiments.


Scheme proposed in [19] also leveraged feature of speaker em bedded in the phone to identify users.

they haven t pointed out how large scale their scheme can be applied to.


3.3 Signature Generation A naive signature generation scheme is to hash (MD5) each page in CCK as the signatures.

such an approach will fail for some modern OSes.


One of their disadvantages, therefore, is their limited ability to identify malicious behavior that has not previously appeared in their training sets.

our statistical testing framework is more .exible because it considers the presence of clusters of certain types of edges without pre-de.ned connection patterns between the edges.


These measures prevent the above attack from producing an inpainting result similar to ours.

this brutal force attack in general would hardly be practical, since it requires applying the inpainting process, which is slow, many times.


The .rst one is from the introduction: l := h; c; l := declassify(h) where c is a command that does not update h. This example is accepted by delimited release because h is considered released even before the declassi.cation statement is reached.

localized delimited release rejects this program because when the set of released expressions is empty, then the memories are required to maintain low-equality as they pass through assignments.


Of the systems listed previously, RiskRanker has the most incommonwithPiOS,inthatboth employprogramslicing tobetter understand appbehavior.

piOS targets iOS binaries for information leaks while RiskRanker looks forpotential security risks(includingplatform-levelroot exploits and background SMS message-sending) for zero-day Android malware detection.


A node s path information is only updated when it receives a packet with a higher DestSeqNum, compared to that stored by the node for a given route.

black-hole attack violates this condition.


They assume the CSI collected over time is benign and there is no identity-based spoo.ng attack present when building the pro.le.

in practice the spoo.ng attack could present at any time.


The results of this section provide us with two conclusions: First, if the load used for training is su.ciently similar to the actual load of the system, we can expect good performance for the detection of zero-day malware.

if the load di.ers from the training load, we cannot expect the detector to be e.ective.


For example, modelling an authentication mechanism to ensure that nonrepudiation properties necessary for user accountability are distinctly specified.

the determination of trust cannot always be ascertained using such absolute properties.


16-bit integers have a range of -32,768 to 32,768.

the IEEE C37.118 protocol defines the polar angle field as a 16-bit signed integer range 31,416 to +31,416 where the units are 104 radians.


These all share the similar philosophy of launching malicious attacks from the virtualization layer.


In short, there is now a substantial literature on how Web and peer-to-peer users aggregate ratings.

there has been little work on how mobile users would do so.


Most of the existing approaches involve parties in cryptographic operations such as key management.

our proposed approach relies on the PMS provider and a client side software to perform cryptographic operations on behalf of the end users.


The algorithm does not attempt to determine which candidate roles to include in such an RBAC policy, to produce a role inheritance relation, or to assign users to roles.

our algorithm addresses these issues in order to produce an RBAC policy.


Research into conference session recordings (Adams & Sasse, 1999b) has identified that those interviewed often rated the sensitivity of multimedia session data on the basis of its technical content (primary level).

users noted that the recorded sessions were invasive if they were viewed, at their secondary level such as:  i) As an educational tool in how not to present at a conference ii) As a research resource to evaluate how people from different ethnic backgrounds act and react in an argument A second issue relating to the acceptability of multimedia data capture and usage is that users perceptions are often reliant on implicit assumptions.


In addition, a recent study by Shay et al., which compared system-assigned passphrases and passwords, found no signi.cant bene.t to either [75].

that study controlled for guessability by forcing relatively low entropies for the distributions from which passwords and passphrases were drawn, thus failing to take advantage of the much larger space of words than characters.


Susan is a friend of Jane and has posted a video which she allows to be seen by all of her friends.

jane s father prohibits her from viewing videos.


Rootkits typically infect the system by installing themselves as kernel modules, which are loaded each time the operating system is booted.

this approach leaves a disk footprint, i.e., the kernel module containing the rootkit, thereby exposing the rootkit to antivirus tools.


Some ciphers (RC5, RC6 and IDEA) obviate large tables.

they introduce operations like modular multiplication (RC6, IDEA) or variable bit rotation (RC5, RC6), which are not directly supported by all NP models.


Key Management At first glance, this key chain appears more complex than necessary.

in practice, it is has proven to be extremely efficient for several reasons: Deriving a symmetric encryption key from the user s password makes sure that access to the data is only possible with the knowledge of the password, which is only available during active sessions.


Barring creative run-time inspection by the library of the host application s data structures, it is up to the developer to pass data to the ad library through the ad library API.

developers have every incentive to hand personal data to advertising agencies, as it has the potential to increase advertising revenue for their applications.


Our system is different from FDR in that it records architectural events inside a VM and does not address multiprocessors and DMA, while FDR is an actual design of a hardware recorder for multiprocessors.

fDR only enables replay intervals of approximately 1 second, does not capture disk state, and does not provide a fully-implemented replayer.


So well before the founding of NSPW in the early 1990s, in- formation security tech-ology had reached the point where its practitioners had largely declaxed success.

many sceptics and critics were finding themselves to be more gen- erally heeded than the established security guru population.


The number of form .elds that are tagged in.uences the probability with which CSN can detect data leaks leaks of untagged .elds go undetected.

tagging every .eld impacts performance and the size of tag logs.


A more ef.cient approach could be to share a pool of TCP connections to the database among all the processes.

we did not attempt to retro.t this codebase to include this optimization.


To this end, we investigate the use of expressiveness-based techniques for ensuring that the access control schemes considered for an application possess the necessary functionality.

unlike prior work, we place application-aware constraints on the types of safety and security properties that must be preserved by an access control scheme while servicing the needs of a particular application.


Besides access control requirements, the availability of services in many applications often further imposes obligation requirements, which specify what actions have to be taken by a sub ject in the future as a condition of getting certain privileges at present.

it is not clear yet what the implications of obligation policies are concerning the security goals of a system.


There have been some proposals to use voice biometrics for authenticating users in mobile banking [19],[20].

to the best of our knowledge, none have been deployed at scale.


We were somewhat successful with an implementation in Haskell [2], a pure functional language that uses lazy evaluation by default.

haskell s referential transparency makes it non-trivial to observe the steps of evaluation, since these are (rightly) left up to the compiler rather than being fully speci.ed by the language itself.


Instead, it is possible to rely solely on the intrinsic security of the PUF construction.

the amount of regular storage space required to regenerate keys is larger than the raw amount of private keys.


In most cases, the oracle mechanism can be embedded in the exploit itself, for example by crafting an exploit so that it will generate side e.ects that can be used to determine if the exploit was successful.

in some cases it is not possible to generate evidence of the e.ectiveness of an attack as part of its execution, and, for those cases, an external oracle that reports on the outcome of speci.c attacks has to be developed.


This binds the input dependency with the code that operates on them.

there are several issues with this approach which remain unproven: (1) Does the combination of inputs and computation required to achieve high integrity encompass nearly the entire application?


He might choose |B| nodes in a row in G. As a result, the user would have to set k to k = |B|.

as k = |B| is considerably larger compared to, e.g., k= Iß · hl, this will result in very high energy consumption, cf.


We therefore use a separate error correcting code for the headers.

bK combine the headers and the payload into one sequence, and uses ExpSim to exchange this entire sequence, which leads to optimal error rate.


Pro.ling apparently addresses some of these shortcomings today (e.g., many legitimate clients behind a NAT would cause the NAT s external IP address to have a higher baseline rate in the server s pro.le).

in principle such behaviorbased techniques can also be fooled : a set of savvy bots could, over time, build up their pro.le by appearing to be legitimate clients, at which point they could abuse their pro.le and attack.


This is made even worse by the ability of a sender to send to any existing multicast group without the consent of receivers or the other senders.

source-Speci.c Multicast (SSM [4]) is relatively robust against DoS attacks.


Particularly, a user can authorize or invoke a security sensitive operation such as token delegation or authentication by tapping his phone to the NFC reader.

the following aspects have to be considered when using NFC proximity to authorize security sensitive operations: First, in case the NFC interface is handled by the operating system, the malware can emulate the proximity to the NFC reader by pretending to receive data from the NFC interface.


The browser runs in a virtual machine and, hence, virtualization is used to isolate the agent from the browser and to provide a trusted path to the user.

they use a type 2 virtual machine monitor (VMM)4 and the agent runs on the host OS (Windows Vista), and they have no further protection of the agent, i.e., no secure storage like binding the agent data to the platform con.guration.


3.3 Gadget Discovery The na¨ive method to locate gadgets within the target binary is to simply disassemble it and search for indirect jump or call instructions.

instructions on the x86 platform are of variable length, so decoding the same memory from one o.set versus another can yield a very di.erent set of operations.


We have chosen to cast our approach on XML documents because of the widespread adoption of this document standard in a large variety of application environments [3].

we believe that our approach can be easily extended to other document exchange formats.


Preserving User Privacy from Third-party Applications in Online Social Networks Yuan Cheng Jaehong Park Ravi Sandhu ycheng@cs.utsa.edu jae.park@utsa.edu ravi.sandhu@utsa.edu Institute for Cyber Security University of Texas at San Antonio San Antonio, TX, USA ABSTRACT Online social networks (OSNs) facilitate many third-party applications (TPAs) that offer users additional functionality and services.

they also pose serious user privacy risk as current OSNs provide little control over disclosure of user data to TPAs.


Likewise, a Wilcoxon Signed Ranks test indicated that participants observed experimental passwords were signi.cantly shorter than their self-reported longest passwords (µobserved = 8.57, µreported = 12.34, Z = -9.217, p < 0.005).

we found that reused passwords were not observably weaker than the passwords of those who claimed not to have reused passwords.


In general, a threshold value of 1 when used with a cryptographic hash function is equivalent to standard unordered treeto-tree algorithms.

a threshold value of 0 regardless of the hash function is equivalent to comparing every element to every other element and impractical for any modern web site due to the sheer number of possible combinations, which is why a reduction of potential matches is essential.


They reason that some form of GetPC code is necessary for determining the location of an exploit s encrypted payload.

many exploits do not follow this convention and attackers can often determine the location of their payload by simply understanding how a particular exploit a.ects machine state or by manipulating it themselves as part of the attack.


These researches, which realizes functions such as inhibition of activity of malicious program in a LAN within a method to mix multiple policies.

these researches do not meet all the conditions of secure state which are proposed in this paper.


If E is ablock cipher or an asymmetric encryption scheme, the attack remains the same for rd-adv.


RKHunter, as explained above, found FLEA and identified associated files.

it only detected some of the files that were modified.


The solution to detect word level obfuscations is to establish a word-word semantic similarity matrix to assess the similarity of strings.

the matrix could be very complicated and large.


The zygote daemon typically uses setuid system call to change the UID to the app s uid.

since this UID already has as many processes as are allowed, setuid fails, and the app gets a process with root privileges.


If a single app makes multiple calls of the same type to the same library, each set of calls is only counted once.

calls sending different sorts of information to the same library, or calls sending the same sort of information to different libraries are counted separately.


If we look at SET 2 (Figure 7) data we can see that the initial PIN problems experienced by the older adults have been exacerbated with the addition of a second set of PIN codes, such that their accuracy levels by week 3 are very poor.

older adults performance with the second set of face codes seems more robust.


3.2 Our Key Techniques Our key techniques could be described in a single sentence: we use microphones to record the output from device speakers stimulated by high frequency audio wave with some special pattern.

it requires more words to explain the rationale behind and how uniqueness, robustness, and stealthiness are achieved by these techniques.


Participants were faster at creating PassPoints passwords than text passwords.

participants were slower at con.rming their password in the PassPoints condition than in the Text condition.


For example, when a network attack, infected host, or unauthorized machine is detected on the network, the security administrator must be able to locate the relevant device(s)  topologically and sometimes even physically in order to perform detailed analysis, cleanup, or removal.

networks are constantly changing in a variety of dimensions: the machines that are connected, the network devices and their configurations, and the connectivity between machines and/or network devices are all in flux.


In this scenario, our previous work relied on Bob s intuitiontodirectqueriestothe mostappropriateprincipals[7].

we would like to resolve such miscon.gurations proactively, i.e., at a time when Bob is not actively interacting with the system.


This technique has been employed by sandboxing systems to limit the sandboxed program s access to system resources.

this method inherently su.ers from the Time Of Check Time Of Use race conditions.


Since the users of SecVisor must modify the source code of the guest OS, SecVisor cannot protect closed-source OSes including Windows OSes.

bVMD does not require the source code of a guest OS.


Each of these transitions may lead to a process with a di.erent frame.

it su.ces to consider any one of the transitions in order to prove that a relation is included in labeled bisimilarity.


Michael Waidner IBM Zurich Research Lab Säumerstrasse 4 CH-8803 Rüschlikon, Switzerland wmi@zurich.ibm.com there should be single signon or one-click features across the entire world-wide web, i.e., transactions should essentially work without remembering anything and typing anything in, except typically for one master password and some OKs.

unless designed very carefully, such features make the situation for trust and privacy even worse and are thus counterproductive.


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


Shoulder sur.ng is a dif.cult phenomenon to recreate in an arti.cial setting, as typically a victim is unaware of an attack taking place.

our setup potentially .ts well to our friend attack threat model as the victim would know they were under observation.


Anomaly-based approaches use statistics on the sequencing of system calls to detect code injections.

a smart attacker can execute additional system calls to make the sequence of executed system calls look normal [50].


We note that ApkScan demonstrated the same issue, implying that ApkScan might have integrated DroidBox 4.1 for its dynamic analysis.

a9 was not e.ective against DroidBox 2.3.


The first idea that comes to mind is to generate a key for the universal circuit instead of C, and include C in the ciphertext when encrypting an input.

this approach will yield large ciphertexts, as large as the circuit size.


There can be multiple subgroups in each layer.

the subgroups need to be disjoint, preferably in the sense of spatial multicast delivery path, at each layer.


Hence, it is natural to require that a policy-based encryption scheme also satis.es this strong notion of security.

the de.nition of this security notion must be adapted to the policy-based setting.


On the one hand, the CK-security and eCK-security are incomparable in general.

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


In addition, the driver may delegate such rights to the passengers.

there may be situations that such policy may not be su.cient.


If a user has access to a truly random bit-string, he can use a deterministic (or cryptographic) PRNG to expand this short seed into a longer sequence which distribution is indistinguishable from the uniform distribution to a computationally-bounded adversary (which does not know the seed).

in many situations, it is unrealistic to assume that users have access to secret and perfect randomness.


Such modeling helps in directly adopting the huge body of heuristic solutions and tools developed for binary integer programming.

these solutions are entirely bottom-up approaches to role engineering.


Studying the results in table 2, we .nd that the storage and update of the t-degree polynomials explains most of the additional storage and communication overhead.

this increase can be justi.ed as follows: First, compared to the group changes of wireless nodes, the encryption and decryption of the multicast data packets happen much more frequently.


Research on methods of authenticating websites to users include security indicators [5, 19], secure bookmarks for known websites [9, 45, 47], and automated detection and blacklisting of known phishing sites [11].

studies suggest that security indicators are ine.ective at preventing phishing attacks [10, 34]; and blacklisting of phishing sites has the issue of a high rate of false-positives and false-negatives [48].


The first thing an agency can do is to take advantage of any enterprise antispam tools on the market to lessen the risk of employee targeted phishing.

these anti-spam tools are not enough to guarantee a company s safety.


This scheme introduces a composite RBAC approach, separating the organisational and system role structures and provides the mapping between them.

our paper proposes a scheme for organisations that each has its own system, content and internal structure.


In particular, control-.ow integrity (CFI) [3] ensures that a program only follows legitimate execution paths.

cFI induces more performance overhead than randomization-based proposals [3].


Similar to the original Nymble scheme, the architecture of Jack separates user identities from online activities by introducing two TTPs.

the TTPs in Jack are engaged in fewer interactions with the user, are unable to deanonymize users, and cannot link user activities across SPs or linkability windows.


Hardness In terms of simple unsolvability, Face Recognition appears promising, sharing many of the same properties that Inkblot does.

its critical failure is its malleability.


The Chipcon CC2420 does have hardware support for the cryptographic primitives that allows for seamless operation with 802.15.4 devices that follow the speci.cation.

as we detail in Section 3.2.3, they do not adhere to the interface outlined in the 802.15.4 speci.cation, so they do not support multiple keys well.


In PEREA, users produce one-time random authentication tokens and must prove that none of the last K authentication tokens is revoked.

the communication and computational complexity of PEREA is linear in a .xed constant K. larger values of K, while favorable, make PEREA considerably slower [29].


It can be observed that whenever the system was in a load management request state, the response state was observed next with the probability of 1.

response also had multiple states depending on the size of the response which was used as a variable in de.ning the state s consisting of multiple s. Therefore, it can be concluded that the model exhibits a temporally deterministic behavior for the system under consideration.


Huge e.orts from both academia and industry have been made on detection and defense of DDoS attacks.

most detection and defense schemes do not directly aim at protecting the victim of attacks itself (e.g., servers) but attack sources or intermediate network units.


A easiest way for CP to acquire forensic data is to terminate the suspect s VM, copy the requested data into external storage, and deliver the storage to the FI [11].

this method is inappropriate if FI need to inspect illegal activities for a period of time.


We apply the same transformation as in the training set to the testing set.

certain feature values in the testing set can still be outside the range of [0, 1], which we set to zero or one as appropriate.


For an ideal clock, the di.erence C(t2)-C(t1) between two time measurements at points t1 and t2 in true time would always be t2 - t1.

due to physical properties (see Section 3.1), clocks based on crystal oscillators exhibit a certain o.set o.setC (t1, t2) = [C(t2) - C(t1)] - [t2 - t1] (1) when measuring such time intervals (positive if the clock is too fast and negative if the clock is too slow).


Under overload conditions, the original Snort implementation misses a signi.cant number of packets, resulting to a considerably lower number of alerts, with many of the labeled attacks in our trace passing undetected.

selective packet discarding signi.cantly improves the detection accuracy of Snort under increased tra.c conditions, allowing it to detect most of the attacks that would have otherwise been missed.


It is obvious that a smaller block size would speed up the process.

a smaller block size will mean the usage of more tags and therefore more levels, which translates into a larger space requirement.


Such biometric characteristic variations have the potential to provide user discrimination; (2) touch data can be easily accessed with very low overhead on mobile devices nowadays.

most of the current work solve the identity recognition problem under controlled environments.


[6], we could base one-signature schemes o. full-blown signature schemes that use number-theoretic constructions.

such signatures take longer to both create and verify, making the CHK method less e.cient in both the encryption and decryption stage than ours.


The .rst approach is to give the users more management/control power, such as: allowing the users to assign and revoke permissions of apps after the installation [8], enforcing usage control with userde.ned policies [1], allowing the users to better control the access to their private data [15].

this approach does not strive to help the users deal with permission-abuse before they decide to revoke some permissions.


Our notion of robustness, however, is somewhat weaker than the standard notion: In our scheme it is possible for a corrupt server colluding with a corrupt user to modify the ciphertext element derived from the ci- phertext of the corrupt user during one stage of the mix process.

it is not possible for the collud- ing parties to modify elements derived from honest users; nor is it possible to modify any element after learning any portion of the output of the mix network.


Our decision to block individual scripts rather than blocking the entire page when an XSS attack is detected means that, like the IE8 XSS .lter, our .lter can be used to disable poorly written frame busting scripts.

because several techniques for disabling frame busting already exist, we recommend that sites replace their circumventable frame busting scripts with the X-Frame-Options HTTP response header [12], which was designed to help mitigate clickjacking.


Since application messages may be scattered over multiple packets, fast signature extraction algorithms have been proposed in Early-Bird [30] and Autograph [14].

it is di.cult for such an approach to detect unknown worms or fast worms that spread extremely fast and leave no time for human-mediated response.


This scheme uses a low-cost hash chain mechanism to update tag secretinformation toprovidethese two security properties.

it is subject to replay attacks[5], andhenceitpermits an adversary toimpersonate a tag without knowing the tag secrets.


These systems work best when there is an outburst of worm tra.c for accurate signature extraction.

they are not su.cient for non-worm and stealthy worm attacks.


CONCLUSIONS AND FUTURE WORK Applications present a convenient means for hackers to spread malicious content on Facebook.

little is understood about the characteristics of malicious apps and how they operate.


One might use a distributed privacypreserving aggregation protocol [1, 12, 37, 40] to compute such statistics.

these are unsuitable for a large population of mobile users where a small fraction of users can become unavailable during the course of computing CTRs.


·m = m, and, if ß ·n > m holds, then attacker A will never be able to obtain an authenticity rating that is higher than the rating of the correct peer.

since we assume that n >> m, and, in particular ß · n > m, it is clear that the attacker will not succeed in getting his pairing accepted as genuine in our scheme.


Websites that follow best practices already salt and hash users passwords instead of saving them in the clear.

because this happens invisibly, users aren t bothered by it.


On parallelism : Sometimes it is claimed that password hashes should be hard to parallelize to increase their security.

this is incorrect, as the task of password guessing is incredibly parallelizable anyway, as individual password guesses can be veri.ed independently of each other.


It would be tempting to assume that Bob s IKE can remove that IP address from the preferred list after receipt of the reassembled message 5.

if Bob s message 6 were lost, then Alice will retransmit the (still large) message 5.


The correctness of the signatures is usually veri.ed by comparing each signature to a second signature that has been approved by some legal authority, i.e., that is contained in a passport.

verifying that the signature is indeed correct is di.culty.


Researchers argue that the lyric and the tune of a melody in a vocal are processed independently in the brain [6].

there are strong connections between the parts of the brain processing them [41, 24].


{X}-1 must be true K b Kb for A| B |r .= B.

this contradicts our assump tion ¬(A| Kb.= B), and therefore, Case 2.1 is not possible.


It is seen from our results that the security of a distributed CR system depends on various factors and that security solutions contribute to performance degradation.

the magnitude of performance degradation can be reduced by the use of a cleverly selected combination of solutions.


In addition, a number of system calls only useful to the system administrator (such as mount) are also unimplemented.

these are limitations of the implementation, not the architecture.


Therefore, we can conclude that none of the tested VMMs implemented a detection technique for checking these types of unauthorized memory region modi.cations.

these attacks only work in intra-guest and intra-host scenarios.


Furthermore, it would be desirable to generalize the blank digital signature scheme and its security model to multiple designated proxies, which seems to be straight-forward by inclusion of multiple proxy signature veri.cation keys into the template signature.

in this naive construction every proxy and every veri.er can determine the set of designated proxies.


One of our hopes was that we might be able to build a model to predict the accuracy and solving time of a captcha scheme given its features.

in our experiments with various machine learning algorithms (e.g.


We shed the light on possible key management schemes for accessing documents within the TVD, in addition to potential document policy structures.

those aspects need further investigation.


It has formalized the patch management process through the Federal Information Security Management Act of 2002 and the National Institute of Standards and Technology (NIST) has published a handbook entitled Procedures for Handling Security Patches.

attitudes about the process vary across other sectors.


We feel that there is reason to expect these policies and their enforcement, which have been extensively studied in database security, to be successfully combined into our approach, as the interactions between the DP and the DC does not have any substantial difference from those between clients and a database.

it remains to be seen how effectively and ef.ciently these techniques work under our framework, which is left as future research.


In this model, the ISN generation algorithm has no clear relationship to time and appears to be pseudo-randomly distributed over short time periods.

when analyzed over long time periods, Figure 2a shows that certain ranges of numbers are used much more frequently than others, e.ectively reducing the 232 sequence space to a much smaller one.


For example, during normal usage, the parameter of a plugin s method may always contain a URL.

during an attack, the parameter may be used to overwrite a function pointer with a speci.c memory address (i.e., a large integer).


Thus, Virtual Machine Introspection techniques become essential, since they simplify the process to acquire evidence for further analysis in this complex system.

virtual Machine Introspection tools for the cloud are usually written speci.cally for a single system and do not provide a standard interface to work with other security monitoring systems.


it is not absurd and in fact is consistent with the price of cryptographic guarantees in systems.


EXECUTIVE SUMMARY  We conclude that security course content and structure are appro-priate for, and in close match with the skill set needed for various security jobs in the technology industry.

we found that neither the present course structure nor the security jobs will be able to mitigate the root causes of the security vulnerabilities.


Furthermore the .rst router will be a guard [34] node.

some users may modify the con.guration of their client to chose paths in a di.erent fashion.


One could imagine other uses of an auxiliary server to support of password-based authentication.

the architecture proposed here is clean and simple, reverts to current practice if auxiliary server .les are compromised, and is even robust against auxiliary server failure (if one allows logins with honeywords).


In these measurements, and somewhat counter-intuitively, we observe that the unweighted graph model results in best entropy (in all three categories: min, mean, and max) Further details are in the discussion section.

we also observe that Figure 6: Average entropy for walk length of 10; all DBLP graphs (S. is single, G and R are geometrical reciprocal distributions of weights, W is weighted, and UW is unweighted, and numbers are to indicate which graph is used: 1-5 are original graphs whereas 11-15 are the dynamic graph model).


In other words, if a compromised node is closer to the root, the bogus aggregated data from it will have a larger impact on the .nal result computed by the root.

in reality none of these low-cost sensors should be more trustable than others.


The embedded seal or watermark essentiallyadds noise on the original data, which has also been the topic of discussion in many works that consider privacy preserving datamining[13, 10, 14, 3].

these techniques typically donotworkdirectly onthe actualperturbeddata(like our technique),but attempttoreconstructthe originaldatadistribution using the known noise distribution that has been added onthedataset[1,17].


4.2 GDOI Events In general, events map to actual messages and vice versa.

since the central messages of the groupkey-pull exchange simply defer computation in order to resist forms of denial-of-service attacks [12] and the NPA does not currently support reasoning about denial-of-service, we behave as if their information load were compounded with the outer messages of this exchange.


Various schemes have been proposed to generate different versions of the software with the same functions and then load each sensor with one of the version.

such of.ine diversi.cation incurs much dif.culty in managing and updating code in sensors.


We note here that the signing process is identical for the signer, both in the original and in the SEM version of the scheme.

it is slightly di.erent for the SEM since it just needs to complete the signature using its own private key share.


In this case, consumers can raise the trust threshold to filter out potentially compromised sources of information.

gradual attacks may not introduce a significant amount of anomaly within the relatively short time window for which anomaly detectors examine the logs.


Perhaps the sensors should be disabled as soon as the virtual keyboard is displayed?

this renders applications that rely on these sensors completely useless as is also stated in [8].


proposed a functional encryption scheme based on stateless hardware tokens that are identical for all users [24].

they rely on computationally intensive operations (fully homomorphic encryption schemes) as well as a powerful tamper proof token carrying out signi.cant computation (signature, noninteractive zero knowledge proofs (NIZK) and succinct non-interactive arguments (SNARGs) veri.cation).


As neither the auditor nor the service provider know tU , this still holds even if both collude.

we note an important difference: while in [35] the challenge (I , {(i, .i)}i.I ) is randomly sampled, challenges in Fortress are generated pseudo-randomly using the pseudo-random bit generator g with a seed extracted with GetRandomness.


Recall that the traditional ideal Zero Knowledge functionality, FZK , allows a prover to convince a veri.er (whose identity is determined by the prover) of the correctness of a statement without revealing any additional information, and without allowing the veri.er to transfer the proof to another party.

as discussed in the Introduction, any proof in the global ROM is inherently transferable: To transfer a proof to party C, the veri.er V simply lets C act as the veri.er, and in particular have C make all the oracle queries herself.


Normally, tboot is invoked by the GRUB bootloader.

to remove the bootloader and BIOSexecutionfrom the switch time,Unicorninvokes tboot using kexecasdiscussed above.


Representative protection schemes which protect function pointers from exploiting including PointGuard [7] and CFI (Control-Flow Integrity [1]).

they require cooperation from developers or code-producers, or su.er from ine.ciency and compatibility problems.


It is known that PCA can be strongly a.ected by outliers [28].

instead of .nding the principal components along directions that maximize variance, robust statistics suggests components that maximize more robust measures of dispersion.


Of course, we cannot prevent the user from being incautious during policy de.nition.

policies are speci.ed using temporal or spacial contexts on data items.


Once the access decision is made, the resource then grants access immediately without the additional step of issuing a ticket.

for the simplicity of discussion, we will continue to refer to a ticket-granting design.


Taking into account the procedures is very important in designing realistic attack scenarios.

it is also very important to remember that a procedure cannot be the only defense mechanism against an attacker.


It provides tremendous connectivity and immense information sharing capability which the organizations can use for their competitive advantage.

it requires more security technologies to protect private information.


also proposed a dependent link padding algorithm which is similar to our algorithm [13].

their analysis are mostly focused on the average delay of the algorithm while we prove the rate optimality of the algorithm.


{SR,LR} Furthermore, note that as per the de.nition of Strict Join (section 3.3 and table 2), the user may access some or all objects that are added after Join time.

in the p-system, we will use the following speci.c interpretation of Strict and Liberal operations which effectively replaces some or all with all .


There are also cases where the operator o.ers the extreme option to completely disable all text messaging services for a given account.

this is satisfactory for a very small percentage of their subscribers.


This 1-3/k yielded memory lower bounds of O(n ) for estimating Fk, for k> 3, improving the previous memory bound of O(n 1-5/k)[AMS99].

by using R´enyi di 1-2/k) vergences,they managed toprove a near-optimalO(n memoryboundfor one-pass Fk estimationfor all k> 2.


Hence, if we consider existing reports and a sample to be malicious if at least 30% of the employed AV scanners reported that the sample is malware, then about 50% of all cracks and keygens we collected would be infected with malware.

fresh reports are based on more recent AV signatures and, as a result, also include more malware infections.


Some cellular companies provide free SMS or low-rate SMS messaging.

many people pay high rates to mobile phone providers for SMS services.


We expect this situation if only some high-security targets choose to specially compile their software with diversity.

if all users receive diversi.ed binaries, we still expect that crafting a code-reuse attack is not possible without ex.ltrating the particular binary under attack.


Resulting temperature readings can only be veri.ed, if there are multiple nodes measuring the same phenomenon, and if there are stochastic correlations of measured data available.

requiring multiple nodes for measuring a single phenomenon is unrealistic in many scenarios.


Although locating and identifying of attacking sources are critical to stop attacks and for legal procedure, a rapid and e.cient prediction of DDoS attacks to happen in the server is more important to reduce damage caused by attacks and even prevent attacks from happening.

this part has not been addressed su.ciently in the literature.


Ourstudyshowsthat with thetwodedicated registers,the register-basedimplementationis morelightweight than the memory-based implementation.

not all sensor processors can a.ord two dedicated registers.


For example, the rDNS record for an IP address 64.12.116.6 corresponds to a domain name cache-mtc-aa02.proxy.aol.com, which suggests that the IP address is used as a cache proxy in the AOL network.

only a fraction of PIP addresses have rDNS records (62.6% in our experiment), and only 1.49% of them contain useful keywords for PIP identi.cation (Table 1).


To be able to securely deny access to RMS protected content, the company has to destroy the key that decrypts the document key in the Publishing License and that is the private key of the server.

without the server s private key the RMS system would not able to decrypt any other content key anymore, because they are all encrypted with the same server key.


Our system would be applicable to these projects.

some projects implement lighter weight lowinteraction honeypots [22], which do not simulate a full machine, but just a subset of services.


Model-checking this property verifies that this model is capable of compromise- free behavior.

john's requests to read the file may be denied repeatedly by transitions of type T4.


Architecture-Driven Smart Grid Security Management Markus Kammerstetter Institute of Computer Aided Automation Automation Systems Group International Secure Systems Lab Vienna University of Technology mk @ iseclab.org  Lucie Langer Safety and Security Department Austrian Institute of Technology lucie.langer @ ait.ac.at Wolfgang Kastner Institute of Computer Aided Automation Automation Systems Group Vienna University of Technology k @ auto.tuwien.ac.at Florian Skopik Safety and Security Department Austrian Institute of Technology .orian.skopik @ ait.ac.at ABSTRACT The introduction of smart grids goes along with an extensive use of ICT technologies in order to support the integration of renewable energy sources.

the use of ICT technologies bears risks in terms of cyber security attacks which could negatively a.ect the electrical power grid.


For instance, in Facebook, showing mutual friends between two identities when a user is looking at another user s public profile may help to defend against such ICA that is creating multiple faked identities of the victim s friends.

these features do not work for the victims who have a large number of friends (e.g.


The success of commercial media streaming systems critically depends on 1) scalability in media distribution and 2) security of the media and the systems.

existing media streaming systems such as content distribution networks and P2P networks lack either security or scalability.


Finally, since TaintDroid is designed to work in a virtualized runtime environment, third-party native libraries are not supported.

taintDroid does support native system libraries in the .rmware because they are in the trusted computing base.


This would give a high degree of entropy.

one mightalso .nd twoclustersof .vepixelseach on the map.


It does not present a concrete design or experimental results of the scheme.

our paper concretely describes a scheme for incorporating intrusion detection operations in the storage management of a hypervisor and shows experimental results.


For example, one could encodeRBAC sessionsasAccessControl Lists(ACLs) forthepurpose of enforcement.

we arguethat our workgives abroad coverage of thepossible approaches with valuable insights for other possible approaches as well.


Apache with CGI processes does provide some isolation, but at a signi.cant cost when compared to Mod-Apache, since each request is handled in a forked process.

at least in its default con.guration, Apache does not run CGI processes in a chroot jail, so if the CGI is exploitable, any vulnerabilities exploitable by a UNIX user on the system are accessible.


On one hand, frequent shred invocations reduce the time window when data is still left on the disk not overwritten but adds overheads for overwriting.

nightly overwrites of data can signi.cantly improve performance even compared with .le systems that do not support secure deletion.


In the x control chart only the first attack activity has been monitored.

all attack activities have been monitored except first attack in the R control chart.


The project was partially declassi.ed in 1995, and many of the decryptions were released to the public [2].

the ciphertexts and cryptanalytic methods remain classi.ed.


One solution for supporting multiple object types, similar to the design of ACLs in DCE [15], is to store multiple ACLs on a container, one for each object type.

that approach may be inefficient if many entries are common to all child objects.


There are a number of techniques that could be considered by smartphone operating system designers: User control on private data access: As in Windows Phone 7, involving user action on each data access helps to mitigate the impact of colluding applications (and more generally, malicious applications).

this also limits applications capabilities; for example, in such an environment, it is impossible for third-party developers to create applications that perform automated backups of private data.


However, the chief drawback of this scheme is that it leads to ciphertext whose size expands linearly with the number of re-encryptions.

we would like to stress that this is the state-of-the-art method as far as unidirectional schemes are concerned, and creating a multi-use scheme without linear expansion of ciphertext for unidirectional schemes is an open problem.


If the unlinkability requirement is relaxed, a TPM suspected of being compromised can be revoked even if the private key is not known.

with the full unlinkability requirement intact, if a TPM has been compromised but its private key has not been distributed to veri.ers, the TPM cannot be revoked.


From a safe sequence, one can de.ne x as y and s as any encoding which satis.es s(Fi(y)) = zi, for all unmarked Fi.This correspondence preserves probabilities.

it does not completely cover the sample space {s, x} since executions such that Fi(x)= Fj (x), for some indices i, j, such that Fi and Fj are not identical are omitted.


Knowing that getting the .rewall, mothership, and Snort systems working properly was very important, those parts of the functionality were heavily tested in isolation.

the interaction of these systems with the scoreboard was not tested before the competition.


This approach is e.ective for user space malware (e.g., botnet programs), which has its own memory space.

kernel malware s code and data reside in kernel memory together with legitimate kernel code and data.


The key idea of symbolic execution is to systematically explore feasible paths of the program under analysis by reducing the search space from an in.nite number of possible data inputs to a .nite number of data scopes (represented by symbolic inputs).

existing symbolic execution techniques mainly focus on non-interactive programs [10, 16, 28, 39].


It may be practical to adapt this approach to detect rootkits on smart phones, because an increasing number vendors are beginning to deployTPMs on their products (this chip is called the mobile trust module, or MTM) [24].

now that the MTM is beginning to be de ployed on commercial smart phones, using the TPM detection approachisapossibility.threekeychallenges mustbeovercomein orderto implementintegrityveri.cationforsmart phones; the .rst two challenges discussed below also apply to integrity veri.cation on desktop computers.


Finally, WebApps that use multiple CAs may nondeterministically fail.

we did not experience any such problems during our compatibility study described in Section 5.1.


Using cookies for cross-frame interactions avoids the security threats present in CDC channels.

hTTP cookies could be eavesdropped in transit or stolen by malicious cross-site scripts.


Based on the results of the preceding sections, we challenge the claim that h is a keyed hash function and, as part of this argument, the claim that h is a one-way function: A basic characteristic of any hash function is that it compresses a message of arbitrary length into a .xed length digest.

the Dusart-Traor´e primitive is speci.ed as a mapping of .xed length inputs onto .xed length outputs, namely Z816 Z816 Ñ Z816 22 2 It furthermore requires that one of the Z82 16 inputs has high entropy as it is used as secret key.


These sites present a traditional desktop user interface, complete with a window manager.

all the applications are JavaScript code hosted from the same domain.


THE BEST OF BREED APPROACH The primary benefit of the best of breed model is that it gives the end users the best applications for their specific roles.

from the perspective of technology support, there are numerous challenges.


LIMITATIONS AND FUTURE WORK The attacker could create a collection of processed tags and compare those to the presented SA challenge.

various characteristics of our approach render it robust against such a scenario.


The identity consumer stores all received artifacts for a speci.c period of time.

since artifacts may be removed from this blacklist when they are still valid in the view of the identity supplier that issued the artifact, a tight clock synchronization between both principals is an important requirement.


It means that when the user is not highly visible , his/her information is most likely buried in the massive amount of online information and becomes invisible.

consider the fact that only a small portion of the general population have disclosed their information  2500 2000 1500 1000 500 0 1234 5678 9 1011121314151617181920 # of positive results (a) Number of positive results in each successful attack.


Many apps collect more information than they need to function and blithely send it to external parties it is simply very easy to get such information on mobile platforms.

it is an open question on where the line should be drawn on such information leaks, and how much apps need to disclose to the user about how their information is being used.


Both systems aim to protect user (patient vs. voter) privacy while providing aggregated result of the private data (statistical function vs. count).

the solutions for voting systems cannot be easily applied to the telemetry systems because of two major di.erences of the problems: (1) The  Table 1: Estimated overhead added by HICCUPS for performing a simple aggregation with 100 caregivers with 1000 records each.


Techniques to reduce linking across sessions, such as disabling cookies, client-side scripting, refresh tags, and caching; using privoxy or TorVM; and others can be applied, and are recommended as standard practice when using an anonymity service such as Tor, to limit the cases in which this is possible.

for some services such as pseudonymous use of online forums, this factor may be unavoidable.


PIP uses early downgrading (ED) and hence does not suffer from self-revocation problem.

as noted earlier, ED restricts functionality over LD thus, PIP avoids self-revocation at the cost of increased security failures.


In the second level Examination activity, none of the roles require more than one member to be active.

the Examinee role has a intra-role coordination requirement, expressed using thisUser in operation precondition of StartExam, which speci.es that each examinee can start only his/her own ExamSession.


The user may permanently allow, permanently deny or grant the permission for one time and thus continue to receive prompts.

we note that applications are generally not written to function with a partial set of permissions.


We see that for this query, the belief sets approach would conservatively conclude that all participants could learn x1 exactly, and that P1 could learn x2 and x3 exactly.

it is impossible for P2 and P3 to learn each other s values to any con.dence.


4.6 Lessons learned from the penetration tests The observations are result of our experience with the penetration tests using qualitative social research and might not generalize to other social environments.

the observations provide an insight of the issues that arose while using the methodology in practice.


To avoid pushing security decisions to the user, multiple security tools such as Zozzle [11] can be executed in the browser to protect the user from malicious web apps.

due to the hardware limitations of mobile devices, this approach will entail severe performance penalties and will not be practical.


Often, a particular statistic is designed that speci.cally targets IPsweep, e.g., the number of different IP addresses for which packets were received in the last tseconds for some suitably small value of t. Once this is done, there is no surprise that the attacks can be detected fairly accurately, based on anomalies in this statistic.

we do not encode any knowledge about IPsweeps in our approach.


Token exchange between WSC and WSP is combined with the ID-WSF Data Service Template process.

token resolution process between WSP and IdP is independent to ID-WSF sequence.


As we assume adversaries to have full control over a node, the core TCB can still be changed.

the tamperproof nature of TPM guarantees that all the changes are genuinely measured.


Jin and Makris proposed using the statistical delay path analysis in wireless cryptographic circuits [8].

as our earlier example showed, it would be easy to place HTs that do not impact any delay paths.


This interface also allows the user to set the current selection as default.

if an application has the SET_PREFERRED_APPLICATION permission label, it can set the default without the user s knowledge.


Extending trust to a small number of nameservers that are geographically distributed may provide high resilience against failures.

dNS forces them to trust the entire transitive closure of the all names that appear in the physical delegation chains.


Typically, trusted computing cannot guarantee that software executed on a computer system is free of programming errors (vulnerabilities) that could be exploited [22].

when the input of a process can be trusted (e.g., signed by a trusted party), 2The remote attestation is either challenged by SB1 or SB2, or both depending on application and trust requirements.


FAF/ASL could, of course, be extended to some extent to accommodate the richer notion of categories that we advocate using.

a richer form of ASL/FAF would be required to accommodate the generality of M e.g., to allow for hierarchies that are not restricted to partial orders, for assertions made by remote authorities, for an extended form of done that, for instance, admits proactive events and more expressive forms of event descriptions, for a generalized interpretation of can , etc.


call and the best precision, but displays a bad recall against distortion.

the precision of the remaining POIs is still good under moderate distortion.


In recent years, security vulnerabilities in online communication and data sharing channels have often been misused to leak sensitive information.

even security enhancing methods are powerless against users getting manipulated by social engineers.


However, the di.erence is not statistically signi.cant.

the di.erence for the bioinformatics based classi.er is 0.01427 and is highly signi.cant.


Both of our address discovery mechanisms are limited: they do not apply to cloud providers that block connections from internal addresses, e.g., Microsoft Azure.

often internal communication has to be allowed, e.g., to reduce costs or to improve quality of service, and there is an increasing amount of tenant-to-tenant communication, [2, 28]; indeed, some popular cloud providers allow communication between internal hosts, e.g., Amazon AWS, Rackspace Cloud Servers.


(In fact, such a method is often called a HIP for Human Interactive Proof rather than captcha, because the latter technically requires that all algorithms and data are publicly known.)

golle [10] showed that the Asirra captcha is vulnerable to machine learning attacks; simply put, it is possible to design an algorithm that can identify cats and dogs with enough reliability that the captcha can be solved with probability 0.1, which is su.ciently often to render it ine.ective as a security mechanism.


Also, the rate at which the worm grows is S(t) I(t)/N.

patching causes the number of infectious hosts in the network to decrease.


Our current system can tolerate this kind of attack up toacertainpoint,sinceit checksthepointer-value constraintsina .exible manner.

it will notbe able todo soif a verylarge number ofpointersinside an objectis manipulated.


In this case, the entire scheme is based only on public and symmetrickey encryption schemes.

if we require function hiding, the authority will need to transfer the correct labels corresponding to f via oblivious-transfer.


It had been considered earlier that, if S-boxes are kept in secret, they can be treated as an additional subkey [6].

a method has been proposed in [5], which makes it possible to easily restore the values of S-boxes used for data encryption.


[10, 23], or even information about speci.c keystrokes on a keyboard [3, 28].

this knowledge Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for pro.t or commercial advantage and that copies bear this notice and the full citation on the .rst page.


Very high success rates in many categories indicate that participants memory was not strongly taxed during Session 1.

this makes the much lower success rate for recall in the Text condition all that more remarkable.


Thus, the communication to update key shares could be saved.

this comes together with the drawback that the obfuscation of the single gateway s keys would not be present anymore.


(1) j.C As there are a large number of consumers, we assume that bk,j and vj(·) are unknown to the ISO.

the ISO knows the historical total demand {d(h, .h)|h .


However, these approaches are mostly interested in increasing the ef.ciency of the mining process; ignoring thus the privacy concerns that may arise from building such global mining model.

several approaches consider the privacy concerns that may arise from mining the data globally [14][22][25][24] [11].


Passwords that are more random (through composition policies or system generation) or contain more characters are harder for password crackers to guess [14].

users have trouble remembering random or complex passwords [7, 16] and resort to insecure workarounds, such as writing down the password or following predictable patterns to meet password requirements [13, 15, 24, 27, 3, 23].


scheme exhibits better performance (connectivity and memory usage) and it keeps the sensor networks secure.

it can only be applied to the group-based deployment model.


A na¨ive approach is to provide isolation for window placement by de.ning a static mapping in which the IC applications only access the IC display and the HU applications access the HU display and, additionally, the IC display within a reserved area.

this approach lacks .exibility since only a prede.ned number of applications can be supported, and sharing is restricted to pre-de.ned display areas.


In particular, when a message is received via the PKS network, the Responder Engine unwraps the PKI message embedded in the rawBytes .eld.

when a response is ready to be sent over the PKS Network, the PKS responder builds up the PKSMessage by including the generated PKI response (e.g., the OCSP or SCVP response) in the message and routes it to the requesting PKS node.


Participants returned for the second phase of our experiment from seven to thirty-eight days from the date of initial set up.

we found that when we isolated data from participants returning on the seventh day for phase two, there was no identi.able correlation between the age variable and memorability.


because the corresponding ACK packets are never sent by the attacker), it would seem intuitive that lowering the timeout values when the queue is under attack would result in more illegitimate request being .ushed out than legitimate ones.

increasing it again when the queue empties out would prevent unadvertently .ushing out legitimate connections when no longer under attack.


Our improved implementation evaluates about 500,000 non-linear gates per second (2µs per gate) on the same host (setting as described above) and about 350,000 non-linear gates per second (3µs per gate) over WLAN (setting as described in §4.1).

[HEKM11] reported 96,000 non-linear gates per second (10µs per gate) over a LAN.3  In the following we show that the online time of our framework when evaluated on the same host as described above (i.e., assuming an ideal network) is up to 10 times faster than that of previous frameworks; we give a comparison for small circuits with FastGC [HEKM11] in §4.2.1 and §4.2.2 (using optimized circuit constructions), for medium size circuits with FastGC [HEKM11] and TASTY [HKS+10] in §4.2.3, and for large circuits with FastGC [HEKM11] and VMCrypt in §4.2.4.


An ERBAC model can be used to specify not only sophisticated access requirements centrally for resources resident in several target systems, but also administrative data required to map those defined access requirements to the access control structures native to the target platforms.

the ERBAC model (i.e., the RBAC implementation) supported in many commercial ESMS products has not taken full advantage of policy specification capabilities of RBAC.


mentioned above, that can be solved with log n EPR-pairs shared between Alice and Bob and O(log n) classical bits of communication.

if only shared randomness is available instead of entanglement, every bounded-error SMP protocol needs O((n/ log n)1/3) quantum bits of communication.


This paper will now focus on the Isolated IDM architecture because from preliminary investigations of the social grant distribution system [11] it became apparent that currently this architecture is in use.

the proposed solution is largely based on the Federated IDM architecture.


The resulting PIP acts as a simple virus on x86.

if we change the ELF header of the PIP to indicate the .le is for ARM, then the program runs as a simple hello world program on ARM.


Initially, the Xen hypervisor allows the execution of any VM of any label.

subsequent load requests will only load the requested VM if it is not in a Chinese Wall con.ict set with any currently running VM.


For example, when a user reads a secure message, the sender s photo appears in the message window.

another popular system displays opaque, non-intuitive information (including a hexadecimal key ID ) in this area [4].


Remember that the map task undertaken by the private cloud only processes the sensitive records within each block (Section 3.2).

there apparently were noticeable overheads associated with initializing the task and seeking for these records within a block, which brought down the performance.


9.5 Summary The con.guration-driven inter-operability approach taken by MPEG-21 means that translation between MPEG-21 and other systems is not always meaningful.

comparing MPEG-21 and OMA provides an example of the kinds of challenges that face the designers of import/export regimes.


Our de.nitions of security do not require schemes be projective.

this property is needed for some important applications.


Such errors are tolerable if the application is trying to infer the city or town for the place of interest.

if a more precise location is needed, then a lower level of noise must be used (E = 10).


The cameramen had decided that hundreds of people were viewing the attendees so more people viewing them remotely would not be more invasive.

the attendees in the real world situation could see who was watching them or not whereas when this situation was made virtual there was no awareness of who was watching.


Typically, provenance information can contain additional information such as time, location, platform, etc.

those present additional complexities that can be addressed in the future work on our approach.


When used to reduce a single number, Barrett reduction is slower than a normal division algorithm.

when used to reduce various numbers modulo the same number many times, by precomputing some value, Barrett reduction can achieve faster speed than modular reductions obtained by division.


Traditionally, NFS supported the POSIX [63] access control model.

nFSv4 includes ACL support based on the Windows NT model and not the POSIX model, since the Windows NT model is richer than the POSIX model.


In the following, .rstly the presence of exactly one malicious compromised node is assumed for simplicity and better understanding.

the key establishment scheme can be extended easily to k attackers.


Speci.cally, a malicious node in the CPS algorithm can sabotage the hash tree dissemination process causing the veri.cation of legitimate nodes to fail.

such an attack is much less severe than the certi.caterevocation attack because (a) it is easily detectable (via the veri.cation con.rmation functionality in the algorithm) and, once detected, countermeasures can then be taken to locate and revoke the malicious node; (b) the attacker can only disrupt one round of the algorithm per attack, with no lasting impact on the network, instead of being able to completely drain the physical battery reserves of a given node; (c) the attacker can only perform the attack from inside the network using a compromised node instead of being able to freely perform the attack from an external device outside of the network.


We can see that our crawling is e.ective, since the percentage of spammers in our targeted (crawled) dataset is 11%, whereas in the random set, it is 0.25%.

the false positive ratio on in both datasets is similarly low.


We have not yet pursued parallelizing the presented applications inside HILTI, as that would involve a number of further aspects in terms of analysis structure and evaluation, exceeding the scope of this paper.

we have veri.ed HILTI s thread-safety guarantees, as well as correct operation of the scheduler, by loadbalancing DNS traf.c across varying numbers of hardware threads, each processing their input with the corresponding HILTI-based parser.


The bu.er used to generate the ClientHello nonce is initialized to all zeros, and we can therefore regard it as a .xed constant.

this is not true for other cases such as PMS generation.


Ether states that it has neither in-memory nor in-register presence, thus it stays transparent for the guest OS.

it does alter a few bits of information that could be returned by the correct con.guration of CPUID.


We are interested in the steady-state performance of the SDP, therefore we use the four-step methodology proposed by Georges et al [13].

we do not run the VM multiple times because executing the benchmark on the same inputs and parameters gives the same timing results in the simulator, so there is no variance between VM invocations.


Note that in an alternative approach this aggregation could be done by encrypting each of the values {EncRp (xi,j )} distributed among caregivers C1, C2,..., Ck, where xi,j is a value known to Ci and j ranges from 1,...,ni the sample size in Ci.

in the case of computing aggregates for medical data nationwide this could potentially involve transmitting millions of values to the aggregator A, instead of sending only one sub-aggregate ai per caregiver.


The access control list data structures and algorithms were designed for services, such as the file system, with only a few types of objects (files and directories), and with only a small number of operations (such as read, write and execute) and data properties (such as owner and creation time).

the Active Directory contains hundreds of types of objects and every object has many properties that must be protected separately.


For .ve hops, SDM and STM provide a 25µs time synchronization accuracy and exhibit a pulse-delay attack vulnerability window of 50µs to 120µs, respectively.

they exhibit no resiliency to compromised nodes.


But this phenomenon could be explained partially by the existence of di.erent security indicators, not directly related to SSL, as identi.ed by Whalen and Inkpen [18].

the e.ect of introducing extended certi.cates, aiming to provide even more information about service providers to users, was studied in [10, 15].


We will investigate as well the fundamental limits in the estimation of the collusion model, in terms of the code length and the type of collusion attack.

the proposed decoding approach brings new possibilities that, to the best of our knowledge, have not been exploited yet in the decoding of traitor tracing codes.


Communication: The UWSN is always connected and any two sensors can communicate either directly or through peers, according to the underlying routing protocol.

messages can be lost and sensors can fail.


[10] attempt to overcome such limitation by specifying policies of expected application behavior.

this approach is more appropriate for developers, as the policies are slightly complex and require knowledge about the expected behavior of the application.


We observe that, in general, the released networks preserve the shapes of the distributions with respect to those of the original networks.

we also observe the increase of paths of small lengths (e.g., 1-3).


Since this topic is complex enough to .ll many books this section can only provide some basic principles and methods for the process of de.ning the authentication trust level.

it should have become clear that with our notion of an authentication trust level everybody is able to provide adequate algorithms to map any authentication method to such a trust level.


In NetReview, routing messages are recorded in a tamper-evident log to analyze anomalous behaviors ofBGP routesbasedon de.nedfault patterns.Inthisway, NetReview can detect invalid routes caused by attacks or con.guration faults and policycon.icts.

netReview does not address the response mechanism to detectedfaults.


They must alsoensureon their ownthatpackagesthey areinstalling are not outdated or have vulnerabilities.

there are many scenarios where a user can use embeddedpackage signaturesin a way that increases security in their speci.c situation.


In order to defeat these attacks, the proxy must be able to di.erentiate a forged report from the legitimate ones.

we cannot employ the traditional authentication techniques such as MAC or digital signatures, because they reveal the sender s identity, hence the user privacy is lost.


HiStar [22] is another information .ow system which provides strict information .ow control and prevents private data from being leaked.

hiStar creates a more restrictive environment for applications by denying any component which reads tainted .les access to the network.


This project differs from others in that there is no direct technical deliverable.

iT research is also well-suited to creating such frameworks and methods and there are numerous other cases of this.


Determining websites sensitivity levels is a non-trivial task due to di.erences in individuals: a website that Alice considers to be sensitive may not be sensitive to Bob.

any websites that are vulnerable to security and privacy breaches should be labeled as sensitive.


Especially in high speed traf.c situation where vehicles moving in opposite directions contact for an instant, the three-way hand shake in the onion voucher model may incur a great deal of mes sage loss.

we note that, unlike safety-related applications in VANETs, ad content itself is not critical information, nor of real time constraints, rather a soft state10.


s scheme is divided into four phases: registration, login, authentication, and password-changing phases.

both the schemes still have security flaws and cannot fully prevent from various malicious attacks.


The adversary simply forwards the obtained message and both adversary and veri.er compute the shared key based on the exchanged public keys.

since the protocol s software integrity of the prover is also re.ected in the platform con.guration, the veri.er will determine the platform con.guration as not being trusted.


4.3 Limitations of the Approach By applying the techniques presented in this section, it is possible to remove all unaligned free-branch instructions from a binary, and to protect the aligned ones from being misused by an attacker.

since our protection mechanism does not remove the free branches, but prepends a short piece of code to protect them, the result of the compilation will still contain some gadgets.


This simple modi.cation can allow queries for excerpts of the payload by checking if all the blocks of an excerpt are in the Bloom .lter.

we need to determine whether two blocks appeared consecutively in the same payload, or if their presence is just an artifact of the blocking scheme.


Though this is weaker notion than the adaptive chosen auxiliary public key attack, we believe it is still useful in many cases.

the security can be upgraded to be secure against adaptive chosen public key attacks,by either assuming random oracles, or requirepolynomially bounded ID (auxiliary public key) space.


s. However, we will explore prov approaches to detect this misbehavior in our future work.We do not consider a malicious-malicious case since an active malicious user and malicious service provider can agree on not following the protocol.

for passive malicious or faulty systems (corresponding to service providers or users) some remedies can be posed.


2.6 Future Work The focus of this work is strictly for firewall authentication in small to mid-sized environments that utilize a small number of firewalls.

for larger environments such as global enterprises this system will not scale adequately.


Previously, a number of key pre-distribution based mechanisms have been proposed for establishing initial trust in Wireless Sensor Networks (WSNs) [13, 8, 11].

they all assume that nodes are loaded with some form of shared key materials before initial use.


Conventional authorization architectures for the Grid have been proposed in a single VO environment.

in reality we often need to handle the situation of several dynamically created VOs.


A naive way to take a consistent checkpoint of the whole system is to pause the server system, take a snapshot, and then resume the execution.

for production workload servers with large disk and raw memory, this stopping-the-world checkpointing will cause intolerable service downtime to the servers.