The relationship is entirely synergistic, and, when running properly, bene.ts all members of the system, including those who view the advertisements.

the corollary is that the system is predicated on each member of the system receiving good value for money (or, the case of the user, value for time).


The propagation of the virus is slowed down signi.cantly when applying ACT.

virus propaga situations Number of Infected Nodes 3500 3000 2500 2000 1500 1000 500 0 Time Figure 5: Non-reinfection Virus Propagation With DQ: Random Topology 4000 3500  Number of Infected Nodes 3000 2500 2000 1500 1000 3000  Number of Infected Nodes Number of Nodes 2500 2000 1500 1000 1000 500 500 0 0 Time Time Figure 7: Reinfection Virus Propagation With DQ: Figure 9: Details of Virus Propagation in the Ranrandom topology dom Network 5000 non-reinfection virus can be calculated as 4500 d i 4000 R0 i = Ph i k , k = 1, 2, · · · , di (2) Number of Infected Nodes 3500 k=1 3000 where hi k, k 1, 2, · · · , di are the neighbors of host i.= 2500 is decreased when a warning signal is received.


This can result in corruption of the static data.

data misclassi.ed as code without such targets just contributes harmless, dead code to the rewritten binary s code section.


In [3], two methods are proposed which make use of a notion of truncated frequency.

those methods cannot be used in our problem due to the following fundamental challenges: Support Counting.


Clearly for users who do not use the mouse, this method will fail to detect an intruder.

the promising results of this initial exploration point toward the need for more work in this area.


These are increasingly supported by technical, architectural, or assurance frameworks intended to facilitate specification and assessment of capabilities.

these frameworks were not designed to facilitate analysis and negotiation.


For instance, when two partners provide broadcast services for users in two overlapping groups, users moving within each group are managed by their local group key distributors (GKDs) and without any coordination between their broadcasts.

when a user crosses from one group to another, security should be transferred between partners.


Until now, no major standard format has existed for describing warnings.

it may be appropriate to build a certain standard format for the warnings.


A resourceful attacker searches local database with data collected from various online sources, including social networks and online public records.

a tireless attacker queries web search engines with his seed information, and untiringly examines the results.


They require some way of marking grid squares either o. or on, so it could still be done in a text-based environment like a terminal.

they are not very accessible and would not interact well with a screen reader, for example.


To verify the .le integrity the reader calculates the MACs using his subset of keys and compares them to the corresponding MACs.

this method allows a group of malicious readers to collude and share their keys.


In Ubicomp, direct observation is often combined with other qualitative methods (for instance, shadowing of and interviewing participants may be combined) [7].

when it comes to studying mobile privacy, there are several obstacles to the use of direct observation.


(2) The attacker s server honestly forwards the first request to the legitimate Gmail s server that (3) returns a redirection header suggesting navigation to https://secure.gmail.com.

(4) before forwarding this and subsequent responses to the victim, the attacker alters them by replacing https:// with http:// for any URLs.


The Linux kernel is a large, complicated code base that makes traditional static analysis dif.cult.

by compiling a copy of the kernel with debug symbols (the -g .ag to gcc) the GNU debugger (gdb) [Free Software Foundation] can be used to extract the types, names, and locations of all static kernel objects.


For example, a set of numeric objects may be statistically downgraded using their mean; an image may be downgraded by lowering its resolution, smoothness factor, etc.

let us consider an aggregation operation that reconstructs a secret x (output) from a collection of its secret shares {yi}(input) using a standard k-out-of-n secret sharing scheme.


Moreover, a security manager is also installed on the merger, which checks for false alarm(if necessary).

it demands for additional computation time and often real time alarm generation becomes dif.cult.


The students all have had at least a year of tertiary mathematics, and some exposure to a computer algebra system (Maple).

the cost of Maple, and the current licensing agreement, means that students are unable to experiment with the software away from the computer laboratories at the University.


Unfortunately, studies have demonstrated that up to 92% of users can be convinced to ignore missing client-side secrets and enter their passwords into phishing pages.

since client-side secrets have already achieved industry acceptance, they are an attractive building block for creating better phishing defenses.


While we do not know the exact RAM usage while the response is computed, it seems very likely that implementing a masking scheme on that controller would exceed the RAM availability.

in contrast to the more than 15 year old PIC16LC58B, state-of-the art microcontrollers or, better smart card controllers are equipped with enough resources for implementing a masking scheme.


The shape of orbit is quite similar to Figure 3.

we can see that if the initial virus population is large, more preda- tors are required to extinguish the viruses.


The essential point here is that, on the one hand, we have certi.cate revocation lists to prevent version-rollback of software components by using old property certi.cates.

the certi.cate revocation list itself must be protected against version-rollback.


A 1.25-KB memory is a trivial cost for modern computers.

with a request cache, roughly 28% of requests have to be examined, and thus suffer a long delay due to worm detection in WormTerminator.


Our goal is to provide support for change management of all protocols and policies associated with SOAs.

this is a huge task, and so we will in this paper focus on a particular type of protocol, trust negotiation protocols.


CASE STUDY INTRODUCED The ADVISE system security analysis method is applicable to a variety of systems at varying levels of abstraction and with varying levels of detail.

to illustrate the concepts introduced in the ADVISE method, the de.nitions in this paper are accompanied by examples from a generic electric power SCADA system.


Such calls not only create inconveniences, but also disturb mental peace.

it is not advisable to ban all telemarketing calls, since they are important marketing tools and a number of customers are in favour of receiving such calls regarding new products/information updates on existing products.


In this approach, keys are as secure as a user s password.

considering user s convenience this is a practical approach as most of the systems today rely on password-based authentication.


Yet, it is still hard to con.rm a user s gender just by comparing results from two applications.

we have noticed that the proportion of male and female gender is more unbalanced in WeChat pro.les.


Existing research on authenticating websites to users include security indicators [12, 30], secure bookmarks for known websites [14, 75, 78], and automated detection and blacklisting of known phishing sites [16].

studies suggest that security indicators are ine.ective at preventing phishing attacks [15, 60], and blacklisting known phishing sites still su.ers from a high rate of false-positives and falsenegatives [79].


Existing approaches use cryptographic protocols for handling delegation.

management of such mechanisms is a very tedious task such as permission revocation [11, 12].


In addition, homomorphic encryption technology can address the privacy protection in situations where a server should blindly perform some processing on the data (i.e., labels 3 and 5).

in nondelay tolerable situations, this technique might jeopardize people s lives.


The results of these experiments show that both methods achieve a very low false positive rate.

the false negative rate detected for the k-Means approach was extremely lower than of the k-Centers approach.


After enco ding, the distance between pairs are estimated by a third-party.

this approach leaks the distances between each record.


It uses the gray-box approach [1]: automatically obtaining .lesystem speci.c knowledge within storage systems by accessing protecting .les and recording its access history inside storage.

our approach uses a white-box approach: using tools that know .le system-speci.c knowledge, thereby creating strict security policies.


Recently several researchers have proposed robust aggregation frameworks, which combine multi-path routing schemes with duplicate-insensitive algorithms, to accurately compute aggregates (e.g., Sum, Count, Average) in spite of message losses resulting from node and transmission failures.

these aggregation frameworks have been designed without security in mind.


The .re.ghters do not have adequate security clearances for terrorist threat information, and they may even be unauthorized to know general information about the speci.c hazardous materials suspected of being in the building.

this information is relevant to their current mission and the information may save lives.


In fact, a lower threshold may be more appropriate: as we describe in Section 5.3 below, a signi.cant fraction of accepted mail is still spam, and, in many cases, SpamTracker captures this spam before the Organization or Spamhaus does.

without ground truth data, it is dif.cult to determine a precise false positive rate, because accepted mail may simply be misclassi.ed spam.


Unlike competing security solutions, this design is unique in that even if the 1Also referred to as the Synergistic Processor Unit (SPU) isolation mode  supervisory software such as the operating system or thehypervisor is compromised, the process isolation is guaranteed.

most security architectures rely on the perpetual integrity and security of their supervisory software to protect and separate the processes.


Game-TS Transcript-simulatability not hold, because from the de.nitions, an adversary that wins Game-TS may lose Game-INV when he didn t get additional help, i.e., transcript t .

this remains an open problem and needs further exploration.


It will take about 20 hours to leak this key with the 0.2 bps L2 cache covert channel.

if using a channel with the maximum bit rate 262.47bps, as described in § 4, leaking the same private would only take about 53 seconds.


Particularly, these schemes may take the threshold-based approach, in which the group key is either agreed among group members or generated based on shares from group members [14, 6, 7].

none of the existing solutions .ts well in WMNs, since they cannot take advantage of or mitigate the disadvantage of the architectural heterogeneity of WMNs.


For example, in an accounting o.ce, a transaction that updates the .les of a customer may be composed by a number of usages.

all those usages, as long as they concern the same customer, should share a common attribute with the same value that represents the transaction wherein the usages belong.


Secondly, the order of components in a RegEx is preserved in the state machine detecting this RegEx.

it may be bene.cial to change the order of the detection of components in a RegEx.


Previous work did not present a comprehensive malware clustering validity analysis system, and the cohesion and separation validity indexes used in [15] were mainly internal validity indexes that required a signi.cant amount of interpretation through manual analysis.

vAMO introduces a comprehensive, fully automated malware clustering validity analysis process that can more readily be used to select the parameters of a malware clustering system, or to compare results obtained using different clustering algorithms.


We have ever used the pixel overlapping evaluation method to construct UC-SimList [1].

the method does not perform well when certain amount of shift of the glyph contour exists.


Existing locimetric schemes such as PassPoints [29] require precise input that can create di culties in communicating assigned passwords to users.

there is no reason that a visual cue could not be used in a password system that required less precise input.


2.3 Advantages and Shortcomings The major difference from the traditional two-factor authentication mechanisms (e.g., con.rmation codes sent via text message or OTP tokens) is that Facebook s SA is less cumbersome, especially because users have grown accustomed to tagging friends in photos.


Presumably, the node s software can then repopulate the ACL table with the appropriate keys.

it is not clear what to do about the nonce states.


Group managers help joining users to generate their secret keys, but do not learn the actual secret keys.

group masters issue secret keys and, hence, know the secret keys of all group members.


In settings, where d2d channel(s) do not exist (i.e., when at least one device does not have a receiver), pairing methods can be based upon device-to-human (d2h) and human-to-device (h2d) channel(s) instead (e.g., based on transfer of numbers [25]).

establishing such channels on constrained devices may also not be feasible.


Second, it analyzes JavaScript code focusing on the syntax of malware code, that is not directly related to code behavior.

focusing on API ref erences allows us to perform a lightweight analysis that is somewhat linked to code behavior, as shown in Examples 2 and 1.


A server can satisfy this condition via a high-bandwidth access link or colocation at a data center.

we expect the more common deployment to be ISPs which of course have signi.cant bandwidth offering speak-up as a service (just as they do with other DDoS defenses today), perhaps amortizing the expense over many defended sites, as suggested in [2].


To solve this problem, Park uses cross domain messaging with HTML5 [7].

park s scheme does not offer a careful consideration of security, and accordingly, remote server s requests and responses can occur without a user s intervention.


As we assume a default of no-access, 100% coverage is not required.

low coverage values may indicate a need for further ACRs.


This was accomplished by adding a coordination requirement on the operations of the Student role accessing the BulletinBoard.

this was very restrictive as the examinee, who had not started an exam-session, was not able to use the bulletin board.


Since freewares usually have a menu for uninstalling, we use it for deleting them.

some commercial tools do not have uninstalling menus, so we used Add/Remove programs of startsettingcontrol panel.


Gatekeeper then They are independent from the handset OS, offer scalability, and provides secure communication using pre-established keys shared can be easily changed or upgraded.

due to security between a remote server and local resource.


According to the protocol model, a packet transmission on link m is successful, provided that for each interfering link l .L,l =m,wehave threshold model is quite close to the additive interference model when the transmitter is close enough to the receiver, provided there is a single interferer.

as the transmitter-receiver separation in 150 |Xl -Ym|> (1+.


4.4 Impersonation Attacks Now let s discuss some possible impersonation attacks as below: (a) An adversary attempts to impersonate a signer P .

i j she/he cannot create a valid individual signature (uj , rj ) to (ik) satisfy Equation (4) because of the lack of the secret key S .


A possible solution is to use the LDRH instruction to load a half word if the processor was in thumb mode before activating the hypervisor handler.

the TLS speci.cation requires that all hypercalls invoked in thumb mode are handled as no operations; in this case there is no reason to access the guest memory to decode the SWI instruction and the hypervisor has been .xed by enforcing this policy.


Note that, in both anonymization approaches mentioned above, preserving the structure and the structural properties of the original graph is largely ignored.

determining structural properties such as the average path length, clustering coef.cient, and the distribution of node degrees is one of the most important data analysis tasks.


For example, an administrator may consider the jamming attack much more important than the selective forwarding attack since the environment could be outdoor and more hostile to potential jamming attackers.

in order to comply with the relation (2), the summation of the two weight factors is one: wSF + wJ = 1 (5) Initially, we treat both threads equally, so it holds: wSF = 0.5, wJ = 0.5 (6) a fair treatment of the above weights could be insu.cient.


In the last decades, we have been very lucky that for most hash functions .nding second preimages is much harder than .nding collisions (since .nding collisions turned out to be much easier than anticipated); hence it may be nice to keep this security margin in designs that need long term security.

there is the concern that if SHA-3 is not as fast as SHA-2 in software, it will not be widely adopted.


Protecting Function Pointers in Binary * Chao Zhang Tao Wei Zhaofeng Chen LiST, Peking University LiST, Peking University LiST, Peking University Beijing, China UC Berkeley Beijing, China chao.zhang@pku.edu.cn wei_tao@pku.edu.cn chenzhaofeng@pku.edu.cn Lei Duan Stephen McCamant Laszlo Szekeres LiST, Peking University University of Minnesota Stony Brook University Beijing, China lei_duan@pku.edu.cn USA mccamant@cs.umn.edu USA lszekeres@cs.stonybrook.edu ABSTRACT Function pointers have recently become an important attack vector for control-.ow hijacking attacks.

no protection mechanisms for function pointers have yet seen wide adoption.


On the one hand, physical access control mechanisms [11] may prevent unauthorized physical access to a certain degree, but are not e.ective against insider attacks.

pervasive encryption, or continuous encryption of all memory (and swap disk space), is done by secure processor proposals, e.g.


Thus, plaintext data is never transmitted in the clear.

the anonymous model assumes that the keys can be exchanged in a secure manner but does not explicitly state how this is accomplished.


In contrast, 5http://en.wikipedia.org/wiki/Secure Remote Password there is no implementation of SRP for Java Cards (even in the latest Java Card speci.cations).

the Java Card environment supports the execution of SRP within hardware even though the explicit operations in the API are missing.


It is not easy to enhance general knowledge on certain topics.

it is still a factor that influences information security and a lot of home Internet users also suffer from information security threats.


If i1,i2reside in different parts of the database, then it clearly suf.ces to read one bit from each of the .rst two devices.

if i1,i2 both reside in the same part, say L, then one of them can be retrieved directly from the .rst device, and the other by reading one bit from each of the other devices and taking the exclusive-or of the two bits.


Users can set their friend network as private and such activity may defend against ICAs.

most of users do not prefer this activity as it also makes their profiles less popular.


[21] had introduced very related works on the area of context-aware access control.

recent studies still show that there exist many open practical problems.


This contextual information can signi.cantly improve the qualityof the client-side enforcement for particular web applications, such as mashup sites.

the downside of such a serverpolicy, is that thepolicy is applicationspeci.c, and therefore requires additional e.ort of the web application developer or deployer.


With the availability of its source code, we can conveniently prototype our system to validate the feasibility of the proposed approach.

we point out that our approach is general and can also be applied to other VMM platforms, such as VMware [2] and Xen [5].


To summarize, the traditional approach is to customize the signature DB in order to reduce the false positives and to reduce the load of administrators.

it would cause the false negatives issue.


A user has a password for each category of accounts.

this step is invisible to users, much the way salting and hashing within websites is currently invisible to users.


This correlation decays in time and eventually drops down to a negligible value.

the correlation decay is not consistent for all ADSs.


One of the designer s should have known better because he was there for all the history of all the generations.

at the time he was inclined to not care about titles and go along with whatever his co-authors suggested for a title, not realizing that it would make describing the various systems more complicated in the future.


Traditional botnets may initiate attacks, such as spam, phishing, click fraud, key logging, key cracking, copyright violations, and denial of service (DoS) [51].

another wave of botnet has become a wider threat during this technologydriven era: mobile botnets.


Alternatively, they can always store the key counter in indelible .ash memory, incrementing it after sending each packet.

since storing values in .ash memory is slow and energy ine.cient, application designers can amortize the cost of writing to the .ash by leasing a block of counter values and storing the lease in .ash memory.


In PipeNet and Onion Routing [34], virtual circuit based routing is introduced.

they assume that network nodes do not move and the topology is .xed after initialization.


Rigorous theoretical analysis suggests that DAS supports an overall password space larger than that of the ubiquitous textual password scheme.

recent research suggests that DAS users tend to choose weak passwords, and their choices would render this theoretically sound scheme less secure in real life.


Systems initialized using personal images [26,37,38] are particularly promising due to the ubiquity of large image collections, in addition due to observed usability benefits where users have had involvement to capture or create the images [28].

it appears likely that the usability benefits of this genre of graphical password are contingent upon subtle attributes of the image sets that are presented to users.


Further, rare words are vulnerable but will not be likely to appear in future messages.

whileitisunlikelythataparticular rare word would appear in a new message, it is still quite likely that several rare words will appear in the message theZipfdistributionislong-tailed meaningthatthetailofit hassigni.cant mass.


As such, generally, there would be four possible guesses which an opponent could 1We do not lose any expressiveness by using a deterministic Turing machine as deterministic and probabalistic Turing machines are computationally equivalent.

the use of a deterministic Turing machine simpli.es the proof.


GENERALIZATION AND LOWER BOUNDS O.ine chaining and the hash-tree scheme have been discussed as conceptually di.erent solutions in the literature, with the former being described as a graph-based signature propagation scheme and the latter as a signature dispersal protocol.

it can be observed that the hash tree also implements a graph structure on the basis of a one-way hash function.


Legitimate senders start with low-level puzzles that cannot compete with the attacker s high-level puzzles.

legitimate senders continue to increase their puzzle levels until they receive a capability.


For mobile access to multiple local wireless LANs, the mobile guest can trivially reserve an escort in each of the LAN and seek help from an apposite escort inside each LAN.

if the mobile guest wants to enjoy free local roaming at real time, then an ef.cient escort registration phase must be embedded in ES-CORT design to assign the guest a nearest/best escort box at real time.


This ensures that we have enoughvarietyof Linux machinesto comparethe accuracyof .ngerprinting at .ne-granularity and coarse-granularity classi.cation levels.

as we will see later, the population bias that it introduces has negative effects on our .ngerprinting tools.


While the certi.cate authority (CA) model for the Web has known limitations [9], because of its (current) wide acceptance, we choose to build on the CA model for world-driven access control.

we stress that the underlying mechanism is interchangeable.


The move to convert old analog biomedical images to their digital equivalents has been largely applauded due to reasons of convenient storage and retrieval, especially in hospital databases.

such a move attracts undesirable tampering of biomedical images which could result in forensic and insurance frauds.


This says that knowing identifying information about an individual, there are at least k records in the database that could (with equal probability) refer to that individual.

suppose that those records also include sensitive information, e.g., if an individual is diabetic.


It allows functionality to continue for all measurements that lie within an acceptable distance from the expected behavior.

signature analysis denies functionality to a limited set of points enumerated outside the acceptable distance.


Observe that accounting for the fact that Tor clients use 3guard relaysby default(as comparedto onein our experiments) would reduce the frequency of them being detected as a bottleneck relay by a factor of 3.

note that our results are conservative since we selected relays from a limited pool of only 25 Tor relays.


OWL (Web Ontology Language) is the Semantic Web standard for formal knowledge representation and communication between systems [8].

various ontology editors are available [9].


Given the increasing reliance on Bitcoin among businesses, the use of Bitcoin in fast payment scenarios is only expected to increase.

given its design, Bitcoin can only ensure the security of payments when a payment veri.cation time of few tens of minutes can be tolerated.


As shown in Figure 3a, beginning at approximately Day 4.7 and terminating on Day 5.5, a DDoS attack is an abrupt increase in the amount of requests per second experienced by a site -similar in the peak request rate to that of a .ash crowd.

as depicted in Figure 3b, the dramatic increase in the request per second rate during a DDoS attack is attributed to the increase in the per client request rate, which is signi.cantly di.erent from that of a .ash crowd or normal usage.


Please note that there exists a solution to the given PBAFSA problem if and only if the  sub encrypted stra is accepted by FSAa for all 1 = a = r. If the above PBAFSA sub problem has a solution mapping eatti , 0 = i = m-1, then one can .nd assignments for variables xi, 0 = i = 127 using Equation 1.

since Skey ac is accepted by FSASAT for mapping eatti , 0 = i = m - 1, the encrypted stra is accepted by FSAa for all 1 = a = r. the encrypted stra is accepted by FSAa only if clausea is true.


RELATED WORK The sub ject of the use of passwords, and alternatives, for authentication has been analyzed at length in the computer security literature.

web users password habits have received far less attention.


[5]) as major advantages of text-based CAPTCHAs over other schemes.

in a small scale test carried out with 20 students in the first author s class in October 2007, we observed that many foreign students whose mother tongue does not use the Latin alphabet performed much worse than those whose first language is based on Latin alphabet (e.g.


Distributed and virtualized systems introduce new vulnerabilities, assumptions, and performance requirements on disks.

traditional storage systems have very limited capacity to implement needed advanced storage features such as integrity and data isolation.


Weexpected infected machinesto connecttousonJanuary25th, which was the day when bots were supposed to switch to the .rst weekly domain name that we owned.

on January 19th, when we started our collection, we instantly received HTTP requestsfrom359 infected machines.


Moreover, the site uses a very complicated JavaScript environment that makes it di.cult for bots to interact with the pages.

the complexity of these sites made them not very attractive to mobile Internet users, who use less powerful devices and slower connections.


That s one of the reasons SSH implements encryption based algorithms to prevent illegal access and enforce data integrity [4].

no matter how secure a cryptographic function can be, it can be attacked with at least a brute force attack [2].


This increases the attacker s risks of being detected.

we assume that the attacker could physically capture a small number of sensor nodes through the use of a PC-class device and some dedicated, specialized hardware such as JTAG [15] equipment.


This resembles the PC operating environment where mutually distrusting users share host resources.

unlike PCs that utilize multi-user operating systems for resource sharing, protection, and management, today s browsers do not employ any operating system abstractions, but provide just a limited all-or-nothing trust model and protection abstractions suitable only for a single-principal system: There is either no trust across principals through complete isolation or full trust through incorporating third party code as libraries.


As to detecting such attacks using snapshot-based approaches, raising the rate of snapshot-taking might increase the probability of detection.

frequent snapshottaking would inevitably introduce increased overhead to the host system.


A customer shouldbe able todisclose to a serviceprovider a view ofhis/herpasttransactions with other serviceproviders in ordertogetdiscounts ortoprovegoodbehavior overthe past.

transaction receipts need to be protected as they may convey sensitive information about a user and can be the target of attacks.


Most of the features are generated from bag-of-words representations of text .elds.

integer-valued features also encode useful information, such as the date when a vulnerability was .rst disclosed, the length of text describing its symptoms, or the ranking of its severity according to other popular heuristics.


A functional TTP does not have access to the secret keys corresponding to the public keys, hence, in some scenarios, it does not have to be unconditionally trusted.

this does not apply to the case of certi.ed public keys.


Thus, changes are made to the other roots leaving the modulated negative real root untouched.

the changes must be symmetrical for the conjugate pairs to avoid possible suspicions.


Thisisbecauseauser maybe morewillingtodisclose less granular location information.

nodes within a level may be assigned di.erent values depending on the sensitivity.


Little attention has been given to user obligations that depend on and afect authorizations.

to be usable, the system must ensure users have the authorizations they need when their obligations must be performed.


Proposed models such as Context-Role Based Access Control (CRBAC) [14], Generalized Role Based Access Control (GRBAC) [13], and Temporal Role-Based Access Control (TRBAC) [2] extend the RBAC model in order to take into account context information (e.g., environmental factors).

the RBAC model and the aforementioned extended RBAC models are not suitable to open dynamic environments and peer-to-peer interactions where we cannot consider the existence of prede.ned roles and user-role association.


For mutate operations the ownership taint should be considered high so that an information flow to a destination is not precluded due to the destination s taint in the owned category.

for inspect operations the ownership taint should be considered low so that an information flow from a source is not precluded due to the source s taint in the owned category.


The performance of asymmetric MIMO con.gurations 2x3 and 3x2 are analyzed and it is found that their energy consumption is midway between the values of 2 × 3 and 3 × 2 MIMO con.gurations.

the 2 × 3 provides better performance in terms of tradeo.


We have discussed ATRA that exploits in-memory paging data structures of address translation.

the mitigation methodology of Memory-bound ATRA that manipulates the in-memory component of the address translation seems to be evident; external monitor should check the integrity of the in-memory paging data structures.


This has been highlighted in the limitations of our work.

a.ect of such attacks would be limited to a particular area.


Ann Cavoukian, Ph.D. Information and Privacy Commissioner of Ontario, Canada The media has been the greatest proponent of freedom of information, freedom of expression and freedom of speech.

the media has also been one of the worst violators of privacy rights through the activities of the Paparazzi and various so-called investigative tabloid journalists.


When the regular user tries to edit other user s information (i.e., sending I2 = K1 .V2 ), delete a user (i.e., sending I3 = K2 .V ) or add a new user (i.e., sending I4 = K3 .V ), the application should reject such input symbols with an ACCESS DENIED page (output symbol O2 ).

the implemented application has two logic vulnerabilities, which are re.ected as the discrepancies between Fideal and Fimpl , shown using the dashed lines with arrows in Figure 2.


Though cookie is encrypted, the vulnerability to abuse the paid service using variables has been found.

dosirak could prevent the message altering and javascript altering attacks by confirming additional user authentication information.


Instead of preloading by factories, the system master secret can be updated and securely transmitted to a tamper-proof device when there is a need.

messages sent by vehicles are classi.ed into two types -regular messages and urgent messages.


It takes a lot of time and work to implement the ISMS.

many parts of the ISMS were processes that we were already doing without any clear rules.


This approach prevents routing table hijacking, and limits the set of IDs an attacker can choose in a targeted attack.

it is not incrementally deployable, and does not support mobility: if a node changes IP addresses, it will need to rebuild its routing table and will be dropped from the routing table of others.


This way, we will be able to achieve a much improved success rate in password guessing than that can be achieved without exploiting click-point information leaked by IDD.

if the prediction of click-points is not very accurate, then the IDD scheme may not be as attractive as other discretization schemes, since a wrong prediction may result in a click-point far away from the center of a Voronoi polygon tile, leading to a significant reduction of the tolerance range of clickvariations, and thus may cause unacceptable false accepts and false rejects.


These systems, however, either make assumptions about the collected information (i.e., that it will not to leak the source identity) [46], or require an algorithm to decide which data are safe to contribute, which may not be easy to devise [45].

our system combines di.erential privacy and separate encryption of answer messages to protect against identity leakage through the data, without any assumptions or prerequisites.


Previous XPath semantics have not distinguished between a subtree of the DOM tree referenced by an absolute XPath, a relative XPath, or a wsu:Id attribute.

a valid semantic of XML Signature must take the location information into account as shown in [12].


A = Au,w, the set E = Eu,w contains strictly less than 1-4 ·10-4 fraction of the edges touching i in GT .

note that since we demand a strict inequality, the claim also implies that A = f. We remark that the claim does not follow directly from the fact that A contains no iteratively expensive indices with respect to either u or w. The latter implies that u satis.es at least 0.1 fraction of the edges touching i, and so does w. it may be the case that there is not even a single edge that they both satisfy.


Other, more interesting uses of labeled images, such as finding sets of images with recurring themes (or images that do not belong to the same set) are possible [10].

it is likely that when a small set of N images is given, and the goal is to find which of the N-1 images does not pertain to the same set (i.e.


Sakkis et al., [30] use a master-slave architecture for stacking k-nearest neighbor classi.er over Naive Bayes to classify emails.

in this work we implement a di.erent form of stacking.


The simplest choice would be to hide behind anonymized networks such as ToR [9].

such effort is not very e.ective because ToR s throughput is low and ToR IP addresses are public.


We could have designed Update to recompute each component Kj " " ,even inthe case where kj " " = kj .= ., causing the key to be fully re-randomized no matter how small the update.

the selective rerandomization strategy gives us amortized constant time for single-step updates, which the indiscriminate strategy does not.


It identi.es the nodes under attack, the magnitude of the thread, and the dangerous cluster.

the localization property of the attack is not addressed.


While the incorporation of the TVD concept in data centers [3, 5] can be expected to be available in the near fu ture, only few research prototypes address the realization on desktop systems [7].

a practical and usable implementation of TVDs for end-users must focus on a secure desktop environment and the end-user experience.


Password managers can reduce a user s memory burden as they only need to remember a single master password [44].

users may have di.culty migrating their existing passwords to the system [10].


As a .nal point of arca de.nitions, we note that a variety of different interpretations of denials of access to categories of principals can be naturally accommodated in an extended form of M.Due to space limitations, we do not give the details of that here.

it should be clear that a d_arca predicate (say) could be used to de.ne denials of permission assignments to categories of principals in essentially the same way that we have used arca de.nitions (and with different interpretations of denials being admitted e.g., denials by intention, denials as physical constraints, etc.).


Ontheonehand, wehaveaninternal mechanism,the link.leconcept,having been introduced in early mobile phone generations.

new functionality is added such as the FileConnection API.


The WRNG does not explicitly initialize R and State.

as with any other stack parameter which is not initialized by the program, these variables are implicitly initialized with the latest values stored in the memory address allocated to them.


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

neighbor discovery between a pure and an adult node occurs much less than between two pure nodes, since most neighbor discoveries throughout the network are between two pure nodes in the early stage of the network.


As shown in the .gure, the unprocessed signal at rx2 seems unrelated to the target message m1 due to the mixture of m1 and m2 plus lack of clock synchronization between transmitters and receivers.

after correcting CFO and gain via intact pilot subcarriers and removing the component of m2, the residual signal is found highly correlated to the target message m1.


Especially, the random uniform sampling schemes show a tendency to concentrate ciphertexts at the edges of R. To lower the probability of the responsible unbalanced recursions, the usage of alternative distributions to choose splitting elements and ciphertexts should be investigated.

the observed sensitivity of all studied OPFs construction schemes against known and chosen plaintext attacks, motivates the further investigation of alternative schemes achieving higher disclosure-resilience under such adverse conditions.


assigning high priorities to spy and cipher processes.

in a real attack, where the adversary does not have privileges to con.gure such parameters, this synchronization issue becomes problematic.


If we choose the conjunction, disjunction, implication method, and aggregation to be min(x,y), max(x,y), min(x,y), and max(x,y), respectively, the risk surface function, as shown in Figure 5, is different especially in some boundaries.

the risk surface in Figure 5 seems to follow the rules in  risk 90 80 70 60 50 40 30 20 10 500 1000 object-security-label subject-security-label Figure 5: The surface using different operations Table 1 as well.


Classical (non transparent, non biometric) authentication solutions, like PIN based methods or graphical passwords, have been proposed long time back.

being non transparent, these methods ask for the aware participation from the user.


This license is signi.cant, as an array read or write could trigger a full re-permutation of the array representation, and the CVM can safely perform this without worrying about preserving the previous state of the permuted array.

there is no requirement that a scalar value be linear a single gate s scalar value can be used by many subsequent gates, for example if multiple expressions refer to a single variable.


in [31], which were zero and .vepercent.

some closer lookatthefalsely accepted sessionsiswarranted.


[21] detect heap-spraying attacks by inspecting the JavaScript string objects to identify shellcode using lightweight emulation [9].

this type of approach have dif.culty in dealing with shellcode obfuscation techniques, such as, shellcode encoding [28, 34], encryption [46], polymorphism [20, 24], and other obfuscationschemes[17,27,31,37].


The tool .nds that performing a zero-higher-order bit fault on k after it is sampled is su.cient to guarantee the fault condition (as we then have k = k » i).

we do not automatically .nd more complex attacks (that use proposition 5) on the algorithms computing scalar multiplications and .eld element inversions.


Therefore, a natural question to ask is whether there is an upper bound on the number of runs in SBDp to produce the correct output.

the proposed protocol produces the correct output in the .rst run of Stage 1 and 2 for many practical applications.


HyperSafe [39] enables the self-protection of bare-metal hypervisors by enforcing CFI.

certain design choices in the host OS make it dif.cult to be applied to hosted hypervisors.


Equation (8) gives a tracing algorithm that accuses an innocent i with probability at most E: output all 1 = i = n such that ai -ai-1 > ..

we must ensure that there isalwayssome i that satis.es (8).


Now by the indistinguishability of lossy and injective functions, the same must be true when f is replaced with a lossy function f'.

f'(x) statistically hides the value of x, because there are on average about 2k =2n/2 '' other values xsuch that f'(x)= f'(x), and all are equally likely.


This feature, on the one hand, signi.cantly improves the expressiveness of trust management languages.

it imposes challenges to e.cient trust policy evaluation.


[14] presented a transformation from an RBAC policy analysis instance to a NuSMV program by letting states correspond to user-role assignments and transitions correspond to administrative rules.

their transformation does not .t for Route.


Weaker continuous on-update requirements could for example be expressed as (update (A).idle ) * which would be implementable.

this form is not suitable for the implementation of a usage time counter as suggested in [10], because no guarantees on the frequency of updates can be provided.


Thus, our approach raises the bar for attackers.

we note this as a limitation and topic of future research.


Pairing would be easy to achieve, if there existed a global infrastructure enabling devices to share an on-or off-line trusted third party, a certi.cation authority, a PKI or any pre-con.gured secrets.

such a global infrastructure may not be possible in practice, thereby making pairing an interesting and a challenging research problem.


This guarantees the secure storage of veri.cation key and releases the platform s burden of keys and certi.cates management.

the secure boot process of MTMs is still based on binary hash values with all its side e.ects.


presented an attack on precise query protocols to ascertain the order of the query attribute values in [11].

their attack can not be applied to imprecise protocols such as bucketization.


In addition, our algorithm relies on an automated prover to simplify the intermediate conditions generated by weakest precondition computations; the prover is specialized to formulae that combine arithmetic inequalities and size constraints; such formulae include many fault conditions, including all those we explore in this paper (see Figure 7).

our algorithm noticeably departs from recent works on program synthesis by its simplicity: indeed, physical limits on the number and nature of faults su.ciently constrain the search space for faulted implementations, allowing us to dispense from using more elaborate techniques that are required to manage very large search spaces (see Section 6).


Have each signer prepend its public key to its message before signing, so that the individual signatures now are (in the MS case) on the enhanced messages pk 1 I m,...,pkl I m. Now, security is guaranteed as long as the enhanced messages are distinct.

this is not enough for security against rogue key attack in our plain public-key model.


It is possible, of course, that user privacy concerns may be greater for personalised systems, where the authentication codes themselves could reflect sensitive race, gender or age information about the user.

we should note that the use of authentication codes in public spaces (such as with an ATM) can lead to observation attacks where both codes and user attributes can be acquired directly.


Some approaches use rule based techniques to specify electronic contracts, e.g RuleML language [14] RBSLA [22].

these approaches do not completely meet the requirements of a generic cloud environment.


This means no data .ow between VMs of di.erent labels will be permitted, so we cannot use Chinese Wall to enforce risk .ow policy.

the expression of con.ict sets for unauthorized risk .ows using an aggressive Chinese Wall policy may still be useful.


Figure 5: Example policy with generated authorization and obligation constraints The approach is a good starting point for understanding the concept and the motivation for semantically-enriched attestation.

one of the major drawbacks of the approach is that property-based attestation is delegated to a trusted third party, which is then responsible for setting up an attestation communication with the client platforms.


To preserve utility, we expect certain aggregate characteristics (a.k.a., feature) of the original graph should remain basically unchanged or at least some properties can be reconstructed from the randomized graph.

as shown in Ta 9(a) .1 9(b) µ2 9(c) h 9(d) Modularity 9(e) Transitivity 9(f) Subgraph centrality Figure 7: Identity Protection K vs.


For this study, we .xed the Phishiness value of unknown tokens to 0.5, which is also equivalent to the default value of robx speci.ed by Robinson s constants in [10].

we do not present all possible adjustments in this paper, as the goal is not to build an ideal classi.er, but rather limited to show the e.ectiveness of our approach in lexically analyzing URLs for discriminating phishing and legitimate URLs.


We did not incorporate any of these optimizations in the current tool because we were mostly interested in having an initial prototype to assess our technique.

we are planning to implement them in future work to further reduce runtime overhead.


Each SSoD policy speci.es the minimum number of users that are allowed to together possess all permissions for a sensitive task.

sMER constraints are mechanisms used to achieve SSoD policies.


Tested by its designers, the MSN scheme was resistant to prior art segmentation attacks.

for the first time, we used a color filling method for segmenting characters in a CAPTCHA.


s scheme, none can meet all requirements.

this paper introduces a new type of DoS attack which is ignored in these research studies to endanger their securities.


At this point, the string is still harmless and cannot be used to execute an XSS attack.

as soon as this string is inserted into the brower s DOM by using the innerHTML property, the browser will mutate the string.


In direct techniques, the target is adjacent to the over.owed bu.er or can be reached by sequentially over.owing from the bu.er.

indirect over.owing makes use of generic pointers in a two-step approach.


In Table 2, where preceding code may be executed, this cannot include system calls, so the only side e.ect is a change to programmemory and CPU state.

recall that the attacker s ability to alter CPU and memory state is already assumed, based on the threat model (presented at the start of this section).


The harness hides all of these details, so the user needs only specify the computation itself, of type DPComp q r v, and a function acting as the differentially private mechanism of type q -> r. A variant of the harness can even accept a query function of the type q -> IO r, which may be appropriate in many cases.

its invocations will be wrapped in unsafePerformIO, so the this function is responsible for maintaining apparent referential transparency.


As with private accounts, this requires special privileges, provides privacy, but does not permit sharing.

it does not require the administrator s involvement for every user.


This approach is lightweight, as it does not require to run a full operating system for each domain, and also scalable, as resources required for each new domain to be created are very modest.

it has a large TCB that includes Android middleware and the Linux kernel.


On the other hand, DFAs have fast matching speed (O(1)) per symbol consumed.

dFAs su.er from exponential space complexity (O(2n)) [11].


F1.php in Figure 1), know how trustworthy their data are, because they know where the data come from.

when F1.php puts all the data together into one HTML page, and presents it to the client-side browsers, there is no systematic mechanism for the server to convey the data s trust state to browsers, so the trust state gets lost in the process.


In this con.guration, a high RFA intensity improved performance by a meager 2.4%.

when we pin the two to the same core, performance improved by 70%.


With ontologies, we can use abstract concepts and clearly identi.able individuals to represent data and to perform inferencing over the data.

we also need the means to represent concrete data values such as strings or numerical values.


However, device manufacturers inevitably customize devices and change artifacts, which makes it harder to .nd the artifacts that exist in every real device.

emulators are much more uni.ed in terms of customizations, which is possibly due to the di.culty in modifying and maintaining software-emulated hardware.


Another possible limitation of the proposed model is the added restrictions on the token type, encryption and freshness requests; these restrictions will prevent the users from utilising certain features o.ered by CardSpace.

these restrictions only a.ect the CardSpace framework because, from the Liberty perspective, token handling will remain the same [10].


the use of internet e-commerce websites was proving to be difficult and online shopping revenues was low [7].


a user s phone number only appears on one webpage) make it very di.cult to precisely extract and collect large amounts of entities from the web.

we have shown that it takes little e.ort for a human attacker to exploit search engines to locate webpages containing such information.


Several techniques have been proposed to utilize the deployment knowledge of sensor nodes to improve key pre-distribution protocols [8, 14, 18, 24].

all these improved schemes assume that the locations of sensor nodes can be pre-determined to a certain extent.


The more information disclosed about users, the more we can trust their opinions and intentions.

this scenario leads to a simultaneous decrease in their privacy.


Peer-to-peer techniques rely on the participation of k peers to ensure k-anonymity, in a manner akin to Crowds [37].

reliance on peers restricts the autonomy of such systems.


NX bit prevents stack or heap data from being executed, so it is capable to protect against code inject attacks without performance degradation.

its effectiveness depends on its proper use by software.


by .rst transforming the programs into an intermediate format in which binary di.ng is more e.ective.

these tools do not provide capabilities required by Android binary auditing.


To prevent identity and link disclosures, one natural approach is to publish a node-anonymized version of the network that permits useful analysis without disclosing the identity of the individuals represented by the nodes.

as pointed out in [2, 12], this simple technique of anonymizing graphs by replacing the identifying information of the nodes with random ids does not guarantee identity/link privacy since adversaries may potentially construct a highly distinguishable subgraph with edges to a set of targeted nodes, and then to re-identify the subgraph and consequently the targets in the released anonymized network.


We did not implement any of these countermeasures, because each seems to involve an unacceptable loss of usability to either bridge operators or bridge clients, compared with somewhat unclear bene.ts in terms of privacy.

we can sketch a solution based on the third point above: The goal is to ensure that the probability a user s bridge is serving is the same in case she is sur.ng and in case she is not.


This illustrates how social norms can change, and how this can, in turn, change formal legal provisions governing private conduct.

in the aftermath of controversial legal cases, the pressure of public opinion can produce questionable responses from a legislature.


8.4 Robustness When Rt introduces arbitrary delays to conceal cache hits, our techniques based on measuring time di.erence between these two events do not work.

techniques based on PIT and on common pre.xes are not a.ected by cache hit delays, since they either do not rely on cache or do not consider RTT.


Backward-secrecy requires that a joining subject should notbe able to read data exchanged amongst the remaining subjects in the past.

information sharing may not be limited to forward andbackward-secrecy.


These operations do not depend on the number of neighbors the router has nor on the path length.

in ICING the router has to look up the shared symmetric keys with each node on the path in a table that contains the keys of all the nodes the router had previously seen on a path.


R.u is authorized to perform Map, Filter, or Bsort operations only if he/she has the read privilege over the stream denoted by R.Objs.STRs.

in case of Aggregate operator the algorithm has to consider two different kinds of access control policies.


This serves as the primary form of security for browsers.

it requires the server to have a digital certificate and not all pages are secure.


Many pitfalls in cryptographic implementations are known to experts, and have been described in books [14], blog posts [21], and talks [15].

many of them focus on specific aspects of a cryptographic system, anecdotal evidence, or specific protocols and applications, making it difficult to draw broader conclusions about the kinds of mistakes that occur in practice.


Service providers could in principle switch to a more secure authentication technology.

rational service providers will only switch to a new technology if the expected bene.ts exceed the switching costs.


5) Internet users may launch general network attacks on encrypted data or tokens.

we assume that the communications among CSPs are secure and authentic under SSL/TLS secure channels.


More importantly, PREC achieves practicability by 1) raising 0 false alarm on the benign applications without native code.

traditional schemes without our classi.ed system call monitoring raise 67-92% per-app false alarms; and 2) reducing the false alarm rate on the benign applications with native code by more than one orders of magnitude over traditional anomaly detection algorithms: from 100% per-app false alarm rate (FSA) and 78% per-app false alarm rate (HMM) to 3.75% per-app false alarm rate (PREC).


Applying SybilLimit naively to the Byzantine Dissidents v 2 problem yields a protocol which costs O(nm) bandwidth to protect against a maximum of o(n/ log n) attack edges.1 Unfortunately, this is more costly than the simple .ooding protocol described above.

the next section shows how to adapt the underlying techniques developed for Sybil-Limit to produce an ef.cient protocol for the Byzantine Dissidents problem.


We then discuss some possible solutions to the routing table vulnerability in processor-interconnect systems and their trade-o.. 6.1 Other Performance Attacks Coherence Message: In this work, the modi.cation of the routing tables focused on request and response packets.

(a) (b) another important class of messages in processorinterconnect is coherence messages and in the Hypertransportbased system, the corresponding broadcast messages.


Thus it is quite easy to supply the user with the proper authorizations and follow up single user transactions to seek signs of intrusion, as all the transactions of the same user are passed via the same connection.

web applications differ significantly from old applications in their mode of working with databases.


For instance, CRBAC [12], GRBAC[11],andTRBAC[2] extendedtheRBAC modelin order to take into account some context dimensions for restricting access permissions on resources.

as with RBAC these models are not suitable to control access on resources in open and dynamic environments with frequent and unpredictable changes, which we cannot assume the existence of prede.ned roles and user-role associations.


Hence there is no privacy concerns on protecting the network topology.

in mobile wireless networks the network topology constantly changes due to mobility.


This impact may then pervade the whole system due to the iterative feedback.

it is challenging to quantify these critical stability boundaries accurately, in order to characterize the impact of the attacks.


Because these guidelines were originally developed for more general tools and interfaces and are available in many di.erent sources, we do not list all of them here.

we give an example of a general usability guideline that is particularly important for ITSM tools: providing help and documentation to users.


As described above, the doctor s key allows her to decrypt documents in many categories.

in order to do this decryption she must .rst derive a key for each appropriate leaf category.


This is not to discount the importance of a formal model.

formal de.nitions for puzzle hardness [22, 15] are only incipient in the literature and would naturally require extension to the outsourcing scenario as a prerequisite for security analysis.


In the second case above the ciphertext s sent by the client to the authority does not correspond to any (simulated) ciphertext it received (from any simulated data owner).

the client could have created s in an arbitrary fashion, without necessarily encrypting a value r that it knows.


While CtRBAC o.ers a system model that explains how the proposed solution could be implemented, the paper does not provide any further implementation details.

dR BACA has been fully implemented and can be used in a production environment.


They leveraged zero-knowledge proofs of knowledge to construct oblivious transfer.

in their work, once people obtain the credentials, they can always access all records associated with these credentials.


More common are web browser toolbars that provide extra cues such as a red or green light indicating overall safety to inform users that they may be at risk [12, 28, 35, 36].

there are three weaknesses with this approach.


Related protection mechanisms: Web application .re walls are server-side proxies that aim to mitigate security problems.

as the OWASP best practices guide on Web Application Firewalls (WAF) [15] states, current WAFs can only prevent Session Fixation if the WAF man ages the sessions itself.


We note that it is more common to associate clearances with principals and not with resources.

the simplicity and generality of allowing both argues against restricting clearances only to principals.


The results (shown in Table 1) reveal that the alternative design was preferred for most aspects (although not signi.cantly so).

the design used in IE was slightly preferred in overall ratings.


In [14], some work has been to control the transfer of personal information between organizations by requiring acceptance of a "contract" of restrictions that must be respected when receiving an XML document.

little work has been done to address the issue of tracking privacy compliance across a B2B network.


We obtained the running times for standard signature algorithms, such as RSA and DSA, by benchmarking the OpenSSL crypto library.

openSSL does not have implementations of aggregate signatures.


For example, checking pool tags and the object size from the OBJECT_HEADER in Windows de.nitely helps verify the object types (both Volatility [30] and MAS [8] use this method to resolve type ambiguity).

kernel rootkits can easily violate these soft constraints to evade and mislead these memory forensic tools.


We intend to investigate this aspect further in the future by capturing real-world user traces that provide the necessary details to analyze the e.ects of various devices and their di.ering capabilities.

we note that technological trends point to increasing capabilities of personal devices, such as laptops, handhelds and PDAs, which in turn provide a rich set of capabilities for users to access .les in much the same way as they do from a desktop PC, such as a trusted corporate terminal.


If a user wishes to prevent both types of semi-cooperative tracking, it would be wise to adopt a third-party blocking policy that checks the domain of the top-level frame both when the cookie is set and when it is read.

as we discuss in Section 5, this setting will not prevent cooperative tracking.


Second, we tried to add another 120 full-coverage Type 2 signatures.

this attempt failed because building a full-coverage protomatcher consumed more than 2GB of memory.


Over the recent years, Intrusion Detection Systems (ID-Ses) [17, 26, 21] have been proposed speci.cally for WSNs, which cooperatively detect intrusions and report possible attacks to a central authority.

these systems are not equipped with response tools that would enable automatic responses and recovery actions.


If names were assigned by some central authority, names would need log(N) bits of entropy for 2 a community of N people.

names are assigned by individual parents.


Speci.cally, during the .rst execution of a program 2 that encrypts a message m, d will de.ne a transition from qi to qi+1 based on the primitive Enc(.i,qi,m).

the second time, the key will be different, and the state transition will be from qi to qi' +1.


The system should provide privacy assurances to device owners beyond unsubstantiated claims offered by service providers.

attempting to provide strong privacy guarantees about software running on the mobile device may preclude applications which are useful and appropriate.


Another attack would be to take over the servers of a popular service that has already been marked as trusted.

since popular services generally are operated by large companies that monitor their services closely, this remains a challenging task.


[12] suggest using Probabilistically Checkable Proofs (PCPs) to validate semantic aggregation in sensor networks.

their solution requires an interactive protocol between the aggregator and the veri.er.


In the other direction, by placing a PMU at Ii (Zi) we observe Ti and Fi via O1.

since Fi,Ti ./VZ , O2 cannot be applied at either of them, so Zi (Ii) will not be observed.


This is also evident from their grayscale visualizations shown in Fig.7 and they appear very similar to the human eye as well.

these families are still classified accurately with our classification method.


If an MD is stolen or compromised, an attacker may misuse it to legally add malicious nodes to the network, give away secrets, and thereby compromise the whole network.

it is fair to assume a tamper-proof, small, and handy MD which is carried around by the user and taken special care of, e.g., a key fob.


in managing access control lists on a per-directory basis rather than a per-.le one [28].

aFS is motivated by conceptual simplicity and storage overhead, not e.ciency in retrieving access control list entries.


EFS transparently encrypts data, but it does not provide integrity of data as well as con.dentiality and integrity of meta-data.

eFS has convenient and simple .le sharing model as compared to TCFS and NCryptfs.


The Ivy project aims to combine SafeDrive with Shoal [3] and HeapSafe [14], which should provide improved isolation when completed.

this combinationwould stillbe missingBGI sdynamictypestate checking andit wouldlikelyperform worse thanBGIbecause both Shoal and HeapSafe can introduce a large overhead.


Currently, XACML uses Status for dealing with errors.

the Status element simply shows the error information inatextfashion, withoutthe abilityto informdifferent entitiesthe need for more actions.


blocks for each level He and for C. Intuitively, the server has to delete more than half of the blocks in any level He or C to incur any data loss.

if the server deletes so many blocks, checking O(.)


But it requires: (i) large training data for SVM; and (ii) prior knowledge of the image attached on palm-dorsa.

other well known systems have spuriously extracted the vein pattern and results in wrong vein matching.


To provide such a joint signature and encryption tool, Zheng [26] introduced signcryption as a primitive, and several subsequent papers provided alternate constructions and improvements [27, 20, 14, 2, 1, 19].

these existing signcryption proposals all leave something to be desired in the security properties they achieve.


One possible, straightforward idea to discover which apps use in-app billing would be to crawl the Play Store and to look at the descriptions of the apps in the Play Store.

app developers are not obliged to disclose that they have in-app billing enabled in their applications.


As illustrated by the above example, augmenting an automaton with these flags can avoid state explosion.

we need a more systematic way to construct these H-FAs, which we propose now.


On one hand, this simpli.es the administration concept, as all entities are handled in a similar manner.

using the role hierarchy may not be  conform with the administration concept of an organisation.


Existing mechanisms are designed to operate in network environments where administrative responsibility is not distributed.

such an approach cannot be applied to the community network environment because it is most unlikely that members would be willing to trust all others unconditionally.


Our model is closely related to the Refereed Games (RG) model of Feige and Kilian [10] where they focus on two unbounded competing servers and polynomial time referee/client.

we are faced with the additional challenges of building protocols with ef.cient honest servers, with a super-ef.cient client and for any number of servers.


This property is captured by a simulator Swhich can interact with the adversary as if he were the user.

sdoesn t have access to the user s secret or public key, or her e-token dispenser D. when the adversary asks Sto make a clone, the environment passes Sa link-id.


This is because the code of lld contains a few trivial functions, and LXFI s compiler plugin effectively inlined them, greatly reducing the number of guards at function entries and exits.

xFI uses binary rewriting and therefore is unable to perform this optimization.


= 0) f alse (otherwise) 20: end for by the matrix-based NFA evaluation.

noting that acceptance is determined by the state (zero or non-zero), the proof simply shows that Algorithm 1 and the matrix-based NFA evaluation behave equivalently in the way states active statuses are updated.


E-Mail which is by no doubt the most frequently used communication channel on the Internet is daily .ooded by scammers and social engineers, although the awareness for social engineering attacks over E-Mail has been raised among the users.

the awareness for social engineering in cloud services and social networks is still comparatively low.


Two International banks in Hong Kong have actually used SPF.

50% of surveyed companies show that they allow open DNS query so that external parties could make enquiry on their internal IP address mapping, which could expose internal system infrastructural information.


The Windows API provides thousands of distinct API calls serving diverse functionalities.

we have short-listed 237 API calls which are widely used by both benign Windows applications and malware programs.


Indeed, the assumption that in the case of stolen keys there would be no or little deterioration in the performance of the biometric only authentication is true only under an unrealistic assumption, that is, the biometric system knows that it is a stolen key and automatically changes its OP.

there is no way to distinguish between a genuine key and a stolen key.


Our design avoided reliance on SSL in order to ensure the design was not dependent on the security of public-facing servers.

the use of SSL in conjunction with our design o.ers further defense against freeze attacks as well as an additional layer of key security when the server and PKI are not compromised.


Wireless ad hoc networks provide suitable environments for such events.

due to the inherent 1 The term association refers to the set up of a connection among multiple devices.


Secure deletion via encryption usually adds signi.cant overheads and requires non-trivial efforts for the proper key management.

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


since for all the honest parties of WCORE, IC-Commitment will be reconstructed correctly(who in turnde.ne F ' (x,y)), no other secret(other than s can be reconstructed. '


Second, it is also possible to combine dynamic analysis with static analysis.

it remains a research problem to integrate them effectively for reverse engineering a complete input format.


In RT , some particular forms of rules are included as part of the model.

we allow rules for de.ning pca, arca and par in (locally) strati.ed logic in general.


G then lets U in, if and only if these three conditions are met.

videoTicket uses av-recordings instead of still pictures (i.e.


Input times based on one keystroke (dictionary passwords) are comparably fast to natural text.

the analysis of internet passwords and random passwords shows that the performance of typing password-like strings is not comparable to natural language.


Not only can these lists be used in building fast-propagating worms [36], they can also be used for targeted attacks, e.g., an attacker looking to exploit a critical infrastructure industry that may use common services, such as the .nancial services industry.

the advent of botnets [7, 10, 33] and other forms of indirection have made it far more dif.cult to discover the true attack source, instead of bot machines which play a small role in the actual process.


3.4 A Note about Law Enforcement For any incident, hopefully the organization will have the resources and wherewithal to deal with the problem itself.

if law enforcement must get involved, CIRT and senior management must realize that there are some downsides.


For example: an electronic motorshouldstopfor n minutes when the motor temperature is higher than x degrees.

the rules are mostly designed to protect the device against users misuse.


The average sending rate of http .ows is 25.6Kbps in the trace.

there are more than 10% .ows having an average sending rate larger than 100Kbps as shown in Fig.


In the case of Capture-HPC, it did better in very few particular types of scenarios.

the overall performance is still not as good as WebPatrol, i.e., the average coverage of Capture-HPC is only 65.3%, still much lower than that of WebPatrol.


The plugins are mainly written in the native language, so they are not restricted by the WebView s sandbox.

to make it more convenient to use, many plugins provide companion JavaScript libraries.


The tutorial contains the basics of building an Android application.

the described interfaces must be carefully secured to defend against general malfeasance.


The implicit grant is a simpler method for authorization, and in a way provides better immunity against developer mistakes since it does not rely on the secure storage of relying party secrets (since this secret is not used in the implicit grant).

as mentioned previously in Section 4.1, the implicit grant is not safe to use for authentication.


For illustration reasons, we selected an RBAC model of small size as example.

as RBAC models can become very complex, the visualization of RBAC models is a challenging task.


4.3 Alleviating cookie theft An intuitive way to stop cookie theft in Web-based attacks is to address XSS.

despite many e.orts to prevent XSS, such as client-side approaches [25, 12], serverside approaches [35], or hybrid client-server approaches [23, 16], XSS remains the top vulnerability [4].


Relevant feedback enhances system usability, especially in systems where permissions change in unpredictable ways depending on contextual information.

providing feedback indiscriminately can violate the con.dentiality of system policy.


In terms of e.ciency, the Workers Computation Phase requires only (on top of the complexity of securely computing f) 5 secure additions, 2 secure openings and the cost of computing Verk(x, t).

as described above, given that the key k is public this can be done by generating a random shared value s and computing ß = s · (t - k · x).


[5], which found that drivers accounted for 70% of the code in the Linux kernel, plugins accounted for 93% of the total code base for our twelve applications.

there is a high amount of variability between projects.


It is important to note that the resource itself is responsible for checking the validity of the ticket.

as ticket validation is not directly related to the enforcement of location constraints, we consider such an issue to be outside the scope of this paper.


During the copying process, the code becomes partially visible to the JIT compiler as the code heap is mapped to the same physical pages as the shadow code heap.

since the MCFI tables have not been updated yet, no branches can jump to the new code, avoiding the situation in which one thread is installing some new code and another thread branches to partially installed code.


asgndP(r,P ) r1.descendants(r,R,RH) The user-permission assignment UPA(p) induced by a hierarchical PRBAC policy p is de.ned by: authUP(r, U, P, R, RH ) = {(u, p) .

authU(r, U, R, RH ) × authP(r, P, R, RH ) |u, p |= con(r)} UPA((U, P, R, RH )) = authUP(r, U, P, R, RH ) r.R In the de.nition of authUP(r, U, P ), all authorized users and permissions of r, including the inherited ones, are subject to the constraint associated with r. constraints are not inherited ; in particular, the constraint associated with a role r a.ects only r s contribution to the user-permission relation induced by the policy.


This implies that no iteration of the cycle in step 2.f is performed.

since the requested operator is Join, the algorithm calls the Secure join operator.


This isbecause in theory, no matter what the results of our .nite test sequence, the token may be running any software at all, perhaps even behaving randomly.

if a token implements its attributepolicyin the manner inwhich we can describeit, i.e.


Such usage scenarios can be implemented through UCON obligations.

the lack of a feasible obligation ful.llment mechanism is mentioned in the literature [6].


For example, URLScan [8] is essentially a Shield speci.c to Microsoft s IIS web server, which uses the IIS ISAPI extension package s hooks for HTTP request interception and manipulation.

most applications do not o.er such extensibility into their protocols.


Notice that our experiment sends messages using spoo.ng, making them just as likely to be caught in a spam .lter as a message that is a component of a spoo.ng attack (such as the attacks described above).

our message does not contain a malicious link (Figure 8(a)) thus it simulates only one of the features of a real phishing attack.


We need to exploit its one-way property and this is the only property we required.

the approaches followed in [3, 4, 6] use particular hash functions provided with additional features and thus also called cryptographic hash functions.


CONCLUSION Wehavepresentedanarchitecturefor managing userobligations, that a.ect and depend on authorization, as part of a system s securitypolicy.

we suggest to maintain accountability of asystembydenying actions violating it.there are situations when the accountability property of a system can be violated.


Fault injection attacks fail to threaten the con.dentiality of the system, because these attacks are based on repeatedly inducing the fault with the same key.


Such an ecosystem should give applications the possibility to install, delete and manage own applets (small applications) on the ETRH.

the user and applications running on the device should not notice any performance constraints and be concerned with limited resources on the hardware (memory, processing speed).


On the one hand, static veri.cation has the bene.t that there is no overhead at runtime.

it often needs guidance from a developer (e.g.


It is easy to see that a k-sparse vector constructed in this way must be a linear combination of some column vectors of H,and can serve as an attack vector.

the heuristic approach could be quite slow for a general H. it works pretty e.ciently for a sparse matrix H, which is usually the case for real-world power systems.


Note that when dealing with aggregate data, standard differential privacy becomes a viable option.

one needs to also examine the loss of utility caused by the added noise.


Presently in VisFlowConnect, the user can select from several hard-coded threshold values the minimum transfer rate that is required for a .ow to be displayed.

this could easily be extended to allow the user to set one or more user-speci.ed transfer rate ranges to display or hide, allowing the user to more closely examine very high speed of very low speed transmissions.


Multpath routing and fake message injection are introduced in [3] to provide receiver privacy.

it concentrates on the tra.c-analysis attack, which determines the location of the sink through the measurement of tra.c rates at various locations.


As disadvantages, it requires a tight synchronization between each pair of reference nodes and TDoA measures are also quite sensitive to multipath propagation.

tDoA provides considerably higher accuracy than RSS.


These companies deploy a large number of servers with different IP addresses to handle the requests for popular web content.

given the nature of reverse proxies, these IP addresses often reside within the same AS, and hence users would be likely to observe the same AS-level path when accessing the web content from these IP addresses (though the content may be hosted on different servers).


One may view the fact that an error state is reached given a request to be a weakness in the policy.

one may also take it to be a statement about the world in which the policy is to function: that no such requests may logically exist.


Flicker application developer should have very strong understanding of the low level hardware to develop its applications.

our approach does not need to change the current applications.


When the privacy must be preserved not only against a third party, but also against the parties that participate in the protocol where the inputs are shared, secure multiparty computation constructions can be used.

when the problem requires processing noisy signals consisting of a large number of samples, typical multiparty computation protocols become too costly in terms of computation and communication complexity.


Hence a corresponding countermeasure is expected to be much more complex and expensive.

guest A escorted guest B need anonymity protection  Figure 4: The Ring Argument in mobile anonymity design the cost of anonymity protection is signi.cantly decreased in the decentralized and localized ESCORT paradigm.


These include Java [17] and Microsoft s .NET environment [9].

these systems take a quite different approach to ours.


That is, a wireless system that accesses the network is authenticated, and then scanned and updated automatically.

if the user aborts the updates, access to the network is still allowed.


isfactorily addressed by relying on the well-known RBAC model [14, 16].

in order to support policies specifying for which purpose a certain data can be accessed by a given role, we need to expand conventional RBAC models with the notion of conditional role which is based on the notions of role attribute and system attribute.


We believe that this is important for any policy model.

a strong assumption is made in the formalisation presented in [10] in that only a single usage process is speci.ed.


Logical isolation of computing resources can help protecting against poorly or inadequately implemented or configured access-control policies.

other potential sources of information leakage often remain.


Multi-Server environment And recently, more efficient authentication schemes are proposed by Tsai, Liao-Wang and Wang-Juang-Lei.

wang-Juang-Lei pointed out that Tsai s and Liao-Wang s schemes have an impersonation attack and a server spoofing[10].


Moreover, if we increase the timing-interval t to greater than 100 packets, the regularity test observes a di.erent number of packets for each t value within each window,asthe setsof t packets overlap with the window at di.erent points, making the test less reliable.

if we decrease the timing-interval t to much less than 100 packets, the regularity test observes a similar number of packets for each t value within each window and the variance for each window is similar, which makes the test more reliable.


Our system had no false positives for the three month period.

our Snort con.guration generated several hundred false alarms per day, even after some effort to remove irrelevant rules.


The reason is that if Bob veri.es Alice s signature on a piece of data, and then the next week, Alice s signature key is compromised, it doesn t a.ect the fact that that old signature was valid.

if an encryption key is used to protect a piece of data, and then the next week, the encryption key is compromised, that old data is no longer protected.


Finally, if a malicious insider at the metadata store also distributes capability tickets, as is done in some systems, then it can be assumed that the adversary also has access to chunks; a malicious metadata store can simply issue itself a valid capability.

without access to the map key, the adversary would not know which chunks correspond to a give .le, and would lack the key needed to decrypt a chunk.


The plan corresponds to a path in the graph from an initial node to the goal.

each state encountered during the plan is not simply (the set of roles in) the corresponding node in the path; rather, each state encountered in the plan may be a superset of the corresponding node in the path.


Modern intrusion detection systems often use alerts from different sources such as hosts and sub-networks to determine whether and how to respond to an attack.

alerts from different locations should not be treated equally.


Among three of them, the real-time jammer has the highest impact.

it is still limited when n is reasonably large.


7.1 FPToncurrenthardwareisfundamentallybroken We have discussed a few solutions to contain the spurious taint propagation, but they are prone to false negatives, and only slow down the outburst of false positives.

the problem is even more serious as there are undecidable cases when the (most common) hardware itself is not able clean dirty very dirty calc.exe IEXPLORE.EXE kd.exe msmsgs.exe svchost.exe explorer.exe winlogon.exe lsass.exe services.exe svchost.exe wuauclt.exe csrss.exe 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Intervals Figure 9.


Towards an Analytic Model of Epidemic Spreading in Heterogeneous Systems Xiaohu Li T. Paul Parker Shouhuai Xu Department of Computer Science, University of Texas at San Antonio {xli,tparker,shxu}@cs.utsa.edu  ABSTRACT Mathematical models have been utilized to help understand the epidemic spreading of malicious codes (e.g., computer virus and worms).

existing such models are either adapted from the ones developed to capture the epidemic spreading of biologically infectious diseases in homogeneous systems, or suitable only for a very speci.c class of heterogeneous systems.


If an observing agent is not able to access its own memory while the program is executed, then the above program can be considered secure, since after termination the state of the untrusted agent is una.ected by the state of the trusted one.

in several scenarios this requirement is not satis.ed: (i) the observer controls a device that is mapped to a memory area that belongs to the untrusted agent, (ii) the code is interrupted and scheduled in a preemptive environment, (iii) memory stores have side e.ects, or (iv) the code is executed in a multi-core setting.


INTRODUCTION The recent advances in technology, especially in computer industry and communications, have made everything available in the Internet.

the worldwide availability of Internet access has created an ideal medium for copyright fraud and uncontrollable distribution of multimedia such as image, text, audio, and video content.


RELATED WORK Mainly two kinds of cardinality constraints are often mentioned in the literature - user cardinality and role cardinality [6, 9, 15].

our approach of using status predicate, an evaluation function and a projection operator to define cardinality constraints allows one to express cardinality constraints associated with all states - role enabling, user or permission assignment as well as activation time including session.


Compared to the arbiter PUF described in the previous section, the RO PUF allows an easier implementation for both ASICs and FPGAs, an easier evaluation of the entropy, and higher reliability.

the RO PUF is slower, larger and consumes more power to generate bits than the arbiter PUF.


5.3 Using Model Checking to Supplement Belief Logic Analysis One way to address issues described in Sections 5.1 and 5.2 is to extend the logic to address the above scenarios.

not only will this make the logic more complex, it goes against the spirit of inference construction approaches to build support for specific attacks.


Copyright 2009 ACM 978-1-60558-630-4/09/0010...$10.00.. Automaton (DFA) is widely used for multi-string matching for its constant matching speed even in worst case.

for character-by-character based matching algorithms, the throughput is strictly proportional to the memory access frequency.


Obviously, without the condition of finding the minimal set of roles, the simplest way to solve this problem is to first select one role from R1 arbitrarily (there are total n choices, assuming |R1|= n), then selecting another role from the rest of R1, and so on, until the selected set R' satisfies Pau(R') = RQ.

with the minimal set of roles condition, the question becomes hard.


Most applications require long-lived state, as they correlate information across packet and session boundaries.

managing that state in real-time requires effective expiration strategies [16].


Since in certi.cateless cryptography, there is no authentication information (such as an X.509 certi.cate in PKI) for the user self-generated public key, an adversary can replace the public key with another one of its choice.

a Type-II adversary (or AII ) is the KGC who controls the generation of the identitybased user private key but does not know the secret value corresponding to the user self-generated public key.


While the .rst two are immediate, the third test required a DFS over the graph representing location types.

the probability with which an access request requires the discrimination of a high number of rules based on the spatial condition is low.


HyperSafe s CFI precision is higher than the classic CFI s, which uses the notion of equivalence classes for ef.ciency at the expense of precision.

hyperSafe does not support separate compilation because it requires a whole-program analysis to build the tables and those tables cannot be changed at runtime.


The widely used code obfuscation techniques, such aspolymorphism and metamorphism,focus on evading syntax based detection.

statistic test and semantic analysis techniques have been developed to thwart their evasion attempts.


In the work [10], the authors propose a multicast protocol to aggregate messages on the basis of XML tree similarity in order to reduce the transmission tra.c in low bandwidth environments.

while a great e.ort has been made to optimize SOAP performances in transmission, less attention has been given to the problem of reducing the overhead of applying security policy rules to a large number of messages to be transmitted.


It is worth reporting that, following the approach proposed in [27] for signature recognition, we also performed tests by employing a Bayes Classi.er, Support Vector Machines (SVMs), as well as Principal Component Analysis (PCA) in conjunction with the metrics given in (11)-(14), in order to improve the authentication performances.

the obtained veri.cation results do not outperform those obtained by using the MEAN statistics, which produces the best achieved EERs and it is therefore employed hereafter.


For instance, whenever attackers desire to spread malware through a drive-by download strategy, they .rst need to exploit popular websites and add malicious code that will divert tra.c towards their browser-exploiting page.

ad-based URL shortening services give this power directly to attackers nearly for free.


If the doctor rarely asks for more quotas in the past, we may consider that the doctor runs out of quotas due to exceptional conditions.

the system may automatically grant the doctor more quotas so that the doctor can continue with herjob.ifadoctor runsoutof quotas frequently,shemay be over-accessing patients information, as her risk scores must be oftentimes much higher than average.


You do not have to provide a photo to get a quote!

this solution is clearly lacking: MileMeter appears to be clearly aware of fraud possibilities and tries to walk the .ne line between accusing their customers of being untrustworthy and blindly relying on customer-provided data.


In this paper we argue how this attack need not affect protocols that do not rely on IP fragmentation, and argue how most protocols, e.g., those that run on top of TCP, can avoid the need for fragmentation.

protocols such as IPsec s IKE protocol, which both runs on top of UDP and requires sending large packets, depend on IP packet reassembly.


in the current Android SDK, this can be done by using the system calls in android.media.AudioRecord and android.media.MediaRecorder.

this mechanism is not practical against non-mutually exclusive sensors, such as the gyroscope and accelerometer, without signi.cant user experience degradation.


Moreover, to facilitate further privacy requisites of LTEbased PSN, for example, PIR algorithms are needed to mitigate the privacy issues regarding .rst responder s actions (i.e., label 1).

the e.ciency of these protocols in terms of communication and computation complexities and end-to-end-delay are poor.


They discovered that increasing the strength of the user id rather than the password is better when increased credential space is necessary.

this study was not speci.c to .nancial institutions and it is possible that their recommendations of allowing weak online passwords are not applicable to that domain.


Isolating untrusted modules can sig ni.cantly lower the risk of the host application being compromised.

cross-domain access is rather unnatural and clumsy.


Basically, it is possible to keep VIDs active without service sessions.

this a.ects among others the interaction with mobility protocols and is subject for future studies.


Unfortunately, this source of information carries inherent limitations of the OSN pro.les  they are static (e.g., interests a user declared at the time of joining the OSN) and coarse-grained (e.g., location information only up to city level).

with Tessellation, the information gained from combining raw traf.c analysis corroborates and compliments the OSN pro.le information and reveals a wider variety of user activities (i.e., device information, social associations, e-commerce activities, etc.).


Currently, there is no obvious way to attack this business model directly, as the most important elements seem to be beyond direct control of the client.

if this were to be the only revenue stream available to Botnet owners it seems likely that many of the smaller Botnets would be economically unviable.


The third and .fth components are provided by several credential technologies, e.g.,IdentityMixer(idemix),U-Prove, orX.509 thatprovide token generation and veri.cation.

so far no efforts have been madetoprovidethe components(2) and(4) andthereby to close thegapbetweenhigh-level authenticationlanguages andlow-level technology-dependent speci.cation languages responsible for the tokengeneration and veri.cation algorithms.


2.2 Multi-Authority ABE All of the prior work described above considers the scenario where all of the attributes are monitored by a single authority.

as we mentioned in Section 1, it seems natural that one might want to divide control of the various attributes over many di.erent authorities.


THE PROPOSED SCHEME Some DLP-based signatures (e.g., ECDSA [16], Schnorr [22]) can eliminate expensive operations from the signature generation $ by pre-computing and storing the components (R, r), where r .

r Z* q and R = a mod p. this approach incurs linear storage to the signer side (i.e., one token for each message).


[3] propose ESPOONERBAC to extend ESPOON with Encrypted Role-Based Access Control (ERBAC) in outsourced environments.

these solutions [2, 3, 12] assume that there is no collusion between auser and a server.


We also note that p1.p4, since the ssn attribute, common to the two permissions, is the key of both the Patient and Employee relations.


Our routing-bottleneck study discovers a new power-law distribution in the Internet.

this power-law is completely di.erent from that of the above-mentioned work for two reasons.


System call forwarding betweenVMshasalsobeenused[27] to improve the .delity of runtime environment forbetter malwarebehavior monitoring, albeitwithout isolationguarantees.

we aim toaddresscompatibility of existingprocess monitoring tools while ensuring their strong isolation in the context of VM introspection.


If A is a tainted address and B is an address calculated relative to A (e.g., B=(A+0x4)), then B will be tainted.

in many cases it might be unreasonable to mark *B as tainted.


[21] propose a method that provides privacy and con.dentiality in the content-based forwarding setting.


Formalizing GDOI Group Key Management Requirements in NPATRL * Catherine Meadows, Paul Syverson Iliano Cervesato Center for High Assurance Computer Systems Advanced Engineering and Sciences Division Naval Research Laboratory ITT Industries, Inc. Washington, DC 20375-5320, USA Alexandria, VA 22303-1410, USA {meadows, syverson}@itd.nrl.navy.mil iliano@itd.nrl.navy.mil ABSTRACT Although there is a substantial amount of work on formal requirements for two and three-party key distribution protocols, very little has been done on requirements for group protocols.

since the latter have security requirements that can di.er in important but subtle ways, we believe that a rigorous expression of these requirements can be useful in determining whether a given protocol can satisfy an application s needs.


This ensures that the Root VM is no longer part of the system s TCB.

we need direct access to sensor I/O devices from the emancipated VM that hosts the trusted sensor software stack.


This includes changes to the activity manager, the package manager and the permission checking mechanisms associated with these components.

we are unable to include the details of this implementation here due to space limitations.


Usability Concerns Our results indicate that password meters both traditional and those based on social pressure can nudge users towards creating stronger passwords.

nudging users to create stronger passwords may have drawbacks if users cannot remember them or choose to revert to weaker passwords.


To the best of our knowledge, the concept of certi.cateless signcryption has not been previously addressed in literature.

a closely related construction, which o.ers authenticated certi.cateless encryption functionality was proposed in [3].


Thus far, Flicker has focused on protecting a security-sensitive PAL from all of the other software on the system.

we have also developed a module to protect a legitimate OS from a malicious or malfunctioning PAL.


compared with the number of users the variety of user reactions was rather large and so precise numbers like 23.1% or so would be more con- fusing than illustrative.


In general, PDG is resilient against several control .ow obfuscation techniques and noisy code insertion attacks that do not modify the data dependency.

some speci.c data dependence obfuscations can be designed to evade this approach.


Collisions reduce the level of anonymity our protocol guarantees because the higher the probability of collisions, the higher the chance the adversary is given in guessing the correct sequence of inputs.

we observe that if the .eld size (i.e., q) is su.ciently large, then the probability of collisions becomes overwhelmingly small.