Indeed, this problem is inherently dif.cult since some aspects of severity are either context dependent (e.g., a mission critical server being shut down may be more severe than a print server) or may be inherently dif.cult to quantify.

the issue of exploitation is far more clear cut  a vulnerability is either exploited or not and the date upon which a working exploit becomes known is frequently documented.


[12] require about one third of the execution time and are about 10% smaller.

they require more PUF outputs and more substancial, 6.5× and over 11× more helper data.


Again, for the same reasons discussed in the previous section, this should not be a problem given careful design of the public interface of the page.

in the event thedeveloperwants tosimplyensure theframescannot reach each other,thisisnot currentlypossible,atleast toourknowledge.


1LP violations at architectural level are potential in the sense that one can never be certain about violations until the system has been implemented.

a number of problems may (and probably will) persist in the .nal system.


In principle, these logs would then be kept inde.nitely on the server, in order to permit retroactive detection of infection.

practically speaking, logs will have to be kept for much shorter periods of time days, weeks, or maybe months.


Capturing Malicious Bots Using a Beneficial Bot and Wiki  Takashi Yamanoue C:workshopsecurity201220120315CIMG0077.JPG   Kagoshima University Korimoto, Kagoshima 890-0065, Japan +81-99-285-7187   yamanoue@cc.kagoshima-u.ac.jp Kentaro Oda Kagoshima University Korimoto, Kagoshima 890-0065, Japan +81-99-285-7474 odaken@cc.kagoshima-u.ac.jp Koichi Shimozono Kagoshima University Korimoto, Kagoshima 890-0065, Japan +81-99-285-7474 simozono@cc.kagoshima-u.ac.jp  ABSTRACT Locating malicious bots in a large network is problematic because its internal firewalls and NAT routers unintentionally contribute to hiding bots host address and malicious packets.

eliminating firewalls and NAT routers for merely locating bots is generally not acceptable.


We consider a new game Game 3 that is the same as Game 1 except that ciph.,S := TEnc(ckey, volatile, (.S, S, vkeyS, skeyS))e=1,...,m is replaced with a ciphertext of random string when F transfers it to terminals.

when it is transferred, this ciphertext of random string is replaced back to the original ciphertext.


In order to contribute to medical research, a growing number of people publish their genomic data on the Web, sometimes under their real identities.

this is at odds not only with their own privacy but also with the privacy of their relatives.


We also launched our attacks on KVM s host OS to identify the differences with Xen s Dom0.

we performed this test only for completeness, as host OS privileges on KVM are equivalent of having entire control over the VMM as well.


Otherwise, it will be fairly easy to cross-referenced several databases in which the user appears to infer new personal information.

pseudonymity is often not su.cient to protect the privacy of users because a combination of locations can also play the role of a quasi-identi.er if they characterize almost uniquely an individual in the same way as the combination of his .rstname and last name.


We implement our data protection use case (see Subsection 2.2) by changing the protection bits on the relevantlogicalpageswhenwe switchbetweenthetwodomains.

this leaves the question of how the address space is shared.


On the one hand, Core P-RBAC should have su.cient expressive power for representing public privacy policies, privacy statements and privacy notices in Web sites, and policies based on privacy related acts, such as HIPPA [25], COPPA[10], and GLBA[26], in the US.

con.icts detection in Core P-RBAC should remain tractable.


McCamant and Ernstpropose adynamic taint analysisforquantifyinginformation .ow[27].Theirmethoddoesnot assumeaparticular input distribution and provides over-approximations of the leaked information along a particular path.

it does not yield guarantees for all program paths, which is important for security analysis.


All of our attacks rely on the production of ICMP messages, so one might be concerned about the e.ects of ICMP rate limitation.

this is not an issue in practice because of the relatively slow speed at which theICMPpackets are produced.


SIO_RCVALL [16] control code (in Winsock), enables a socket to receive all raw packets.

winSEND is just interested in ICMPv6 messages that are related to NDP messages and left the normal TCP/IP stack to handle the other traffic.


At least O(r) of u s .ngers are honest, and these honest .ngers collectively know all of 4SybilLimit s solution is a subtle sampling-based protocol which each honest node uses to estimate r. 5The sampled nodes may themselves be added to the routing table as .ngers, reducing the overhead of the sampling protocol.

6Naively, this addition seems to increase the routing table s size by a logarithmic factor k. note that an average edge is known by O(log m) honest .ngers: therefore, the sets returned by the honest .ngers should be redundant by a logarithmic factor.


5.1 TCP SYN Flooding Attack TheSYNFloodingAttackconsumesscarceresourceson theserveranddeniesservicetolegitimateusersbyexploiting  Spaces P(E1) Expectednumberof packetsneededto obtainatleastone occurrenceofE1 Numberofpackets neededtoobtain atleastoneoccur-renceofE1with99% probability 1 0.0121 83 380 2 0.0241 41 189 3 0.0362 28 125 4 0.0482 21 93 5 0.0603 17 74 6 0.0723 14 61 7 0.0844 12 52 8 0.0964 10 45 9 0.1085 9 40 Table1:Tradeofbetweenspaceallocatedforrouters'tableiscomputedforarouteoflength30,sop:033. aweaknessintheTCPprotocol.Anattackerbombards theserverwithSYNpackets.TheserverfollowstheTCP protocolandrespondstoeachwithaSYN-ACKpacket, allocatesresourcesforaconnection,andwaitsforanACK fromtheclient.Theconnectiontimesoutandtheresources arefreedonlyafter3minutes,soalargenumberofmalicious packetsquicklyconsumeallresourcesavailableontheserver.


In instance 2, the user can call EPKG[-r1]×EPKG[r1-sA+ sRA +r2]×EPKG[sRA]if it obtains EPKG[sRA], which will never be available to her.

the registration phase must be inspected more closely to reveal the attack possibilities, which we do in the following.


Conceptually, the thinner asks clients to pad their requests with dummy bytes.

instead of having to know the correct amount of padding and communicate it to clients, the thinner does the following.


Aho-Corasick is an efficient multi-pattern matching algorithm so we expect that it may help to reduce the number of the external memory accesses.

aho-Corasick algorithm is based on simulating a state machine and a random access pattern on the states of the machine could incur a larger overhead because we might have to read into the internal memory a large number of bytes to access just a few bytes in the external memory.


Moreover, the problem of unicast security has been extensively addressed in traditional networks throughout several years of evolution, yielding extremely mature security association management protocols such as the Internet Key Exchange (IKE) protocol [3] employed in the IPsec framework, or the handshake phase of the Transport Layer Security (TLS) protocol [4], proven adaptable to contexts (e.g., layer 2 authentication with EAP-TLS/TTLS) other than web security for which it was originally conceived.

extending these approaches to resource-constrained wireless nodes requires careful investigation and is the subject of this work.


In order to prevent such transfer of credentials, the model we formalize ties credentials to a biometric (a uniquely identi.able physical human characteristic).

the authority cannot be allowed to read the user s biometric directly, in order to protect the user s anonymity.


Another example is a denial of service attack, where attackers could remove some or all access rights to rooms in the building, rendering the building unusable by its occupants.

attacks on the building are not limited to attacks on the building security system.


In this regard, by calling a particular subscriber several times, the network will send the same TMSI to a certain tracking area.

the paging messages contain several TMSIs.


In 2012 a research study considering existing attacks regarding the authentication in the Cloud [27] was published.

this research does not provide in depth security analysis of the authentication modules within the Cloud and the relation between these modules.


They assume customers could be able to understand how their personal data will be used and, in case they agree, disclose them .

under the untrusted environment, we believe that users can not set cost (penalties) on the data elements by themselves for the lack of specialist knowledge, unless they know the potential threat previously which may be caused by the data disclosure.


The model was built based on literature review on Gov-IS and Software Engineering principles.

it introduces an extensive list of benefits, barriers and benefits, extracted from the conducted survey on the state of the art on Gov-IS.


A viable approach is to explore current applications and systems to .nd de facto roles embedded in existing user permissions, leading to what is usually referred to as role mining.

a key problem that has not yet been adequately addressed by existing role mining approaches is how to propose roles that have business meaning.In order to do this, we provide a new formal framework that also enjoys practical relevance.


Such a rule models the policy that does not allow a surgeon to enable the Surgeon role in the OperatingRoom1 outside her working hours.

let us assume that, under the same space and time conditions, the event S urgeryI nP rogress becomes '' ' visible, i.e., s '' = (s, t , e ) and SurgeryI nP rogress .


The active adversary is a malicious entity that actively attempts to break in and compromise an archive.

a passive adversary s actions are restricted to eavesdropping on communication channels.


The block sequence numbers provide a temporal ordering of blocks in the .le system; the block with the highest sequence number was written most recently while lowest number block is the oldest.

the sequence numbers do not directly tell us the exact write time of a block.


But in order to deceive a legitimate reader (tag), the fake tag tA (fake reader RA ) has to generate valid response.

this is impossible in our protocol as two distinct random numbers are involved in each interaction.


Access control is extended to concepts, and ontologies.

they do not extend disclosure control over partial ontologies, complete with relations between disclosed concepts.


In the traditional authorship attribution problem, studied texts were long articles with few authorship possibilities as in the case of Federalist Papers .

electronic data may neither be long nor does it haveafew possible authors.


They proposed a method to evaluate the risk of an application based on its permission requests.

our work in this paper aims to explore the application of role mining in the Android security framework.


A SMIL .le, e.g., contains information about how single media assets are arranged.

with M3O we aim at representing metadata about parts of the media that are not necessarily equal to or included in the physical structure de.ned in the SMIL .le.


On one hand, relevant heuristics that contribute much to classi.cation naturally get higher importance scores.

redundant heuristics that exploit the same artifact/token as other heuristics are assigned zero or lower importance scores.


A naive approach would be to compose these policies into a single information .ow graph and evaluate the resultant graph.

such a graph would be prohibitive in size, preventing e.ective analysis.


X will use e to sign messages sent to the chatroom X,i that there is no transferable proof that he has signed any messages in the chat transcript.


The fac t that the auxiliary data may come from either the same or a di.erent domain/context with the anonymized data makes 1Also, di.erential privacy [9] was developed to protect the privacy of interactive data release.

it cannot defend against structural data DA attacks which breach the privacy of non-interactive data release [2][3][8][9].


In the coating PUF, a sensor array on the top metal layer measures the unit capacitance of coating of random dielectric particles for signature [3].

both of them resort to the special material or equipment.


If the face capturing in each authentication trial is also 3D, this approach is robust to 2D media attacks.

3D face recognition is still in its infancy.


The smaller we divide the interval, the more subtle di.erences the distance re.ects.

the bin should not be so small as to enlarge noise.


company to whose networks the user aims to gain access to, who acts as controller since he provides the MUSES mobile application configured for its company information system and network.

it is possible that the company delegates the actual act of the processing of the personal data to another entity (the processor), who will in that case process the data on behalf of the controller (Art.


The SID is not security-critical data before authentication as the user is still unknown and neither the user nor the channel are trustworthy.

after the authentication process has been passed successfully, the same communication channel with the same name has become trusted and security-critical.


Although the OSes do not always enforce the assumptions where these heuristics work, in most of the cases, it produces correct results quickly.

as shown in [27] and in our results, some malware can evade this heuristicbased approach.


A better performance is only achieved by Jsand which is able to almost perfectly detect all attacks.

jsand generally operates o.ine and spends considerably more time for analysis of JavaScript code.


The sender node then uses each key to separately generate authentication/integrity information for each packet to satisfy each node along the path.

the highly restricted packet size in WSNs (e.g.


We omitformaldescriptions of these building blocks due to lack of space and refer the reader to [22].

we brie.y review garbled circuits before describing our contributions.


Many issues of incremental change design are open and require additional research [25].

[26] in their study to define project success, found that the highest-ranking process component was the development team having clear and well-understood requirements.


To maintain low embedding distortion, transform-domain watermarking schemes [17, 18, 22] always watermark some selected coefficients in the mid-frequency of the host image in order to minimize the embedding distortion.

we observed that many of the schemes [17, 22] watermarked only some selected coefficients while leaving most coefficients unprotected in order to minimize the embedding distortion.


WISPr constructs an HTTP page that embeds the encrypted version of the original page; this page can be cached in the network.

a client needs to download a key from the server in order to decrypt the content, and WISPr only works for static content.


In traditional access control models, security administrators specify whether an information consumer can access a certain resource.

in practical healthcare environments, it is information consumers (e.g.


An information object such as an image is often available in di.erent formats and resolutions, i.e., in di.erent information realizations.

this feature is often requested by conceptual multimedia metadata models [20, 15].


The document refers its readers to its Web site to look for more details in the Canon Security White Paper.

a search on Canon s international Web site produced no results.


Many sound clustering method have been put forward in machine learning and pattern recognition field.

one regular expression cannot be considered as a sample point since it has no conventional similarity to others.


Given the fact that all instructions on a 32-bit RISC architecture are 4 bytes large, this turns out to be a non-trivial task: only 0.34% of the 32 bit words consist of 4 alphanumeric characters.

we show that even with these severe constraints, it is possible to build an interpreter for a Turing complete language, showing that this alphanumeric shellcode is Turing complete.


Several of these works also perform speci.cation inference (e.g., [6], [13], [15]).

none of the speci.cation inference techniques presented in these works can cover the range of access control .aws in a purely black-box way.


A page table entry has three bits (the PAT, PCD, and PWT bits) that index into this register to determine the cacheability of its mapped memory.

attempting to write the reserved memory type into the IA32_PAT register will trigger a generalprotection fault [15].


Source codes in Fig.1A are converted into instructions in Fig.1B by the Flash JIT compiler.

if it is executed from 0x110F, it will be executed as a sledge (Fig.1C) which in turn provides a stepping stone for drive-any shellcode.


For privacy and data protection reasons, a database request shall be designed only to have yes/no answers; queries for mandatory, optional, and additional data should be placed separately.

queries for optional and additional data should be allowed only if the query for mandatory data has been confirmed.


Among them: increased workload and narrow error margins because of proximity to terrain and other aircraft.

on .nal approach, a pilot may rely on visual references (runway and visual approach slope indicator lights) or the Instrument Landing System (ILS) than on the MCIS.


Although it is unclear how much semantic discrimination humans use in solving Asirra's binary classification problem, we have experienced that in many cases, substantial low-level features in the images aided humans to distinguish cat images from dog images.

rather than an IQ test, a CAPTCHA is designed to let most humans easily pass in a short time.


Previous signature schemes, such as aggregate or ring signatures, only deal with attacks in the one-dimension setting (e.g., .. parties) which can be considered as attacks in Case 1 and Case 2.

for SAA scheme, we have to consider attacks in Case 3 with two-dimension settings (.. × .. values).


A machine adversary can still make use of exploited popular websites, and have a large number of innocent users to solve the distorted images.

for Uvauth captchas, only recognizing all characters is not enough, and semantic interpretation is required to learn whether the feedback is positive or negative.


In densely-deployed sensor networks, the expected degree of a node is high.

in this example, for simplicity, node u has only three neighbors v, w,and x as in Figure 3.


That is, even a computationally unbounded receiver cannot learn anything about the value committed from the commitment.

a probabilistic polynomial time (PPT) sender can only reveal the commitment with one value under the discrete log assumption.


In his case the policy consists of a list saying which user has access to which record, and the user authenticates to the server openly.

our protocol employs a more powerful attribute-based access control paradigm, and guarantees user anonymity.


It has been discussed to .nd a matrix A to maximize the difference between the encrypted data and the original data [9].

since there is no way to verify how accurate a random guess is, this type of attack is ineffective, in general.


Therefore, extending the hypervisor is one possibility to implement the channel mediation and the crumple zones.

since the mediation policies are highly application-specific, this approach would require building/configuring a custom hypervisor for each protected application.


Now the server can reuse its previous computation, as that computation already processed the previous log; instead of performing the computation again, VE R -SU M can look up the cached result of the function.

the result by itself is not enough; the server must also construct a valid computation history.


An adversary cannot get the relation between a ciphertext and a trapdoor.

a malicious receiver can generate a trapdoor corresponding to each keyword of his choice using his secret key and can obtain the relation between the ciphertexts and the trapdoor through interacting with the email server in real environment.


Due to uni.ed design methodology, the same hardware is used for IP core protection during normal operation.

the following operational changes are incorporated for variable key based protection: The dummy .ip-.ops now forms an N bits shift register.


(freely) available or that the primitive is incompatible with existing cryptographic infrastructure.

in other cases the reason is simply that we do not know whether the software is correct.


It has been mentioned that 2t syndrome coef.cients are needed for evaluating the correctsymbols transmitted, in case of errors.

if any t continuous syndromes are zero, we may conclude that thecode word is either correct or uncorrectable [3].


The installation process of an application was considered in details in the previous section; it is not altered from the developer perspective, but is changed from the user angle (installation may fail now).

it is worth mentioning that if an app is installed from a TruStore market, all consequent updates must come from the same store.


The .rst oneis tosimplyaskhypervisor tointerveneandforward the system call (by crafting an interrupt and preparing the appropriate execution context).

it will unfortunately impact the entire production VM execution.


As a result, the value of t should be as large as possible.

according to the way of modifying M1 shown in section 2.4, the message freedom from mt to m15 should be larger than n. In our attack on MD4(P || C), message m14 and m15 are padded messages, where the freedom is 0. message m137 can be randomly 62RPC is utilized in our attack.


These two latter approaches follow the straightforward way of considering all possible combinations of values, although they do not actually correspond to any XACML combining algorithm.

the remaining XACML combining algorithm can indeed be captured by relying in the 4-valued Belnap Logic.


Scanning memory with object signatures to detect the stealthy rootkit has been proven to be a powerful approach only when it is hard for adversaries to evade.

it is di.cult, if not impossible, to select .elds from a single data structure as robust signatures with traditional techniques.


The existing exploit vertices will then carry the .nal metric score TS (instead of the BS in the static case), which has a similar role as the calculated scores in the case of static domain (as described in Section 3.2).

in the static domain, the .nal score is calculated based on the base score and the causal relationship between this exploit and others, whereas in the dynamic domain, the .nal score of each exploit will depend on four factors: The base score, the temporal score, the causal relationship between exploits and others, and the previous time slice (this will become clearer later when we discuss the two concrete cases).


The secured version incurs alarge overhead, whichishardly surprising considering the fact thatfor eachbusinesslogic service theprocess needs toinvoke theCrP,IdP and RBAC services, and applies and checks theXML signatures.

the measured resultsindicate that the current implementationleaves roomfor additional optimization.


Security toolbars can be valuable in warning the user about fraudulent websites.

they are only useful when the user views them as helpful and takes full advantage of them.


For example, an in-vehicle radar system might not alert the vehicle to danger around a mountain curve.

as we have already noted, to be useful all control systems have to be designed to minimize damage or loss of property or life even when denied external sensor data; the data from RSUs can never do more than enhancing the basic capability of the vehicle s behavior without the RSU input.


These restrictions mainly include: 1) a mobile device usually has a smaller screen size than a desktop computer; 2) a mobile device needs to be operable in non-stationary environments such as on public transit.

mobile devices provide additional features such as touch screen, which may not be available in traditional settings.


X.509 certificates do allow timed and one-time revalidation through CRLs [25] and OCSP responses [37] issued by Indirect CRL Authorities and Designated OCSP Responders (what we have called VAs).


Barnett also tried to use cookie name to identify authentication cookies and apply HttpOnly tags [8].

his approach requires server-side e.orts and works only with Apache.


We acknowledge that a complete redesign of the NFC initiator would be a more e.ective way to improve physical security.

such a clean-slate approach may prove challenging in practice due to the need of involving many players (from IC to device manufacturers).


System administrators and technical savvy people not only think many existing cryptography products are useful but also usable, at least to some extent.

when viewed by majority of end users who do not have the technical background on cryptography, key and password management, authentication, and the complexity for using cryptography products can be the hurdles for making these utilities usable.


We are aware that this might change with further advances in hardware virtualisation technology, for instance hardware assisted page tables.

a detailed performance comparison is beyond the scope of this paper.


Computer simulation results have shown that MC-CDMA is a promising scheme in the frequency selective fading channels.

mC-DS-CDMA can maintain a stable BER performance while the number of users increases.


This implies that the pipelining model would eventually slow down the I/O threads if the analyzer threads cannot catch up with the input rate.

the one-thread-do-all model avoids this problem since it naturally adjusts the pattern matching throughput to its own input rate.


Most similar to ours is Alekhnovich s scheme [4]7 that uses the (decisional variant) of the standard (dense) parity with noise problem.

he too needed v to use noise level of less than 1/m.


If we compare impact of the most intensive SMS stealer with the impact of the most intensive photo stealer (red curves), we easily notice that stealing text messages is more noticeable process on the micro-architectural level.

stealing 50 photos results in transmission of 225 Mb, and stealing 1700 sms messages leads to uploading 85 Kb data.


Android provides per-app isolation for data .les belonging to di.erent apps.

this per-app .le isolation does not apply to stored photo .les, as photos are stored in the external storage location, /sdcard.


[30], when blocks need to be shu.ed, the client downloads the blocks, shu.es them locally, and uploads them back to the cloud in order to avoid increasing the the client s storage.

in our multi-cloud construction, one of the clouds just shu.es the blocks and sends them to the other cloud and the other cloud simply stores them and does not need to send the blocks back to the .rst cloud.


Beyond dynamic analysis In summary, purely dynamic analysis is a reasonable fit for tracking information in realworld examples.

under some circumstances, we have manually aided the analysis with upgrade annotations, in order to increase the accuracy of the dynamic approach.


The hash engine in our prototype hardware has lower throughput and higher latency due to the limitation of Ethernet I/O, and it runs at a much lower clock frequency (125 MHz, which is also limited by the Ethernet speed) compared to that of the software hash function (3.33 GHz).

in a real storage system, these limitations can be easily removed by using an ASIC as the P chip.


Their scheme takes constant time in revocation check for both the prover and the veri.er.

their scheme requires every group member to update his membership private key each time a join or a revoke operation takes place.


The main idea of this algorithm is to move the rest of the code from the point where the grant operation is executed to the granted function.

because we cannot return to the callee, we need to move the code in a mirror way, changing the return statements to call statements that call a mirrored function.


For example, the rule: Professors can update StudentRecords expresses that the class or the category of subjects Professor can perform all actions of class update on the resource class StudentRecords .

the low-level policy (LLP) expresses a set of assignments between individual entities of access control and their corresponding classes, such as Bob is a Professor , the .le SR1 belongs to the group StudentRecords .


If machine learning algorithms can accurately predict the web credibility by using the selected features, the system is able to detect any attackers (thus stage 2, which will be described in the next section is not necessary anymore).

it is extremely dif.cult, if not impossible, to identify all powerful features in such a complex system.


They all contain a mechanism to unmask the input data, perform the basic S(x) (where x is an 8-bit unmasked data) and re-mask it with another constant.

these new S-Boxes would clearly be a source of .rst-order information leakage if implemented in logic gates, as the unmasked variable would be associated to an actual net.


Microdrivers and BitVisor are similar in that they run only a performance or security critical part runs in a trusted domain.

the functions of parapass-through drivers include not only a part of device drivers but also a part of device models, and the actual implementation of the drivers is signi.cantly different from existing code.


Level l is an upper bound on the information that the oracle is permitted to use to reason about the termination behavior of command c. In Section 2, this level is implicitly assumed to be L. Level l ' is an upper bound on what information is allowed to be leaked by (non)termination of program c. This level is only relevant for budgeted semantics, as explained below, and in Section 5 it is implicitly assumed to be H. We do not place any restrictions on the relationship between levels l and l ' .

if l ' g l then the termination behavior of the loop is permitted to reveal no more information than the oracle uses to reason about termination behavior, and so the budgeted semantics give no additional bene.t over the standard semantics.


We cannot calculate the corresponding percentage for the determined attacker without crawling private photos (we discuss the ethical reasons for this in §5).

we simulate this scenario in §4.2 and .nd that we are able to pass the SA tests on average with as little as 10 faces per friend.


In a direct mapped cache, a particular data block can only be stored in a single certain location in the cache.

a data block can be placed in potentially any location in a fully associative cache.


3.2 Web Site Scanning Technology Web Site scanning technology is not new and there are a number of vendors that provide tools to scan an organiza- tion's web site.

two of these vendors, WatchFire with their WebCPO software [24] and IDcide with their Pri- vacy Wall software [12], have specialized in scanning web sites for privacy problems.


The IDS interface also provided an option of quick tuning, which looked like a good way of avoiding the speci.cation of all the default rules of the IDS (more than 1,000).

without real tra.c it was impossible to assess the tradeo.s associated with this option.


Thus, the prepare for relations between the intrusion alerts (i.e., detected attacks) is intrinsic to attack strategies.

in the correlation model, the prepare for relations are between speci.c intrusion alerts; they do not directly capture the conditions that have to be met by related attacks.


We thus spend vast amount of resources to block tra.c that attacks us rather than block attacks before they leave a network.

recurring malcode is an Internet-wide problem and one possible Internet-wide solution is simply to .lter all miscon.gured and malicious tra.c before it reaches its destination.


Even in a perfectly functioning encryption system (consisting of file, database or media-based encryption),, data could be compromised in one of many layers above the encrypting layer.

encrypting at the application layer allows implementers to encrypt data at the highest possible layer in the stack, leaving little wiggle-room for the attacker to compromise the data.


Most .nancial institutions, including these two, use the social security number as the initial user id, but give the user the option to change it to another value.

some sites are more explicit about the importance of changing the user id.


Both these datasets 4http://www.nist.gov cooperate with the Metasploit framework to gather data on exploits.

it is important to note that, if an exploit is featured in EDBor OSVDB, it is not evidence that some company or individual actually reported to have su.ered the exploitation in the wild.


Establishing Pairwise Keys in Distributed Sensor Networks Donggang Liu Cyber Defense Laboratory Department of Computer Science North Carolina State University Raleigh, NC 27695-8207 dliu@unity.ncsu.edu ABSTRACT Pairwise key establishment is a fundamental security service in sensor networks; it enables sensor nodes to communicate securely with each other using cryptographic techniques.

due to the resource constraints on sensors, it is infeasible to use traditional key management techniques such as public key cryptography and key distribution center (KDC).


As a result, CFI is effective at preventing control-.ow hijacking attacks.

past .ne-grained CFI implementations do not support separate compilation, which hinders its adoption.


The most common example of a passive proxy is a standard HTTP proxy [11].

in our architecture the infrastructure is acting as an active, or nontransparent proxy, which is monitoring and modifying content as it passes through.


Only one sandbox is constructed for all native code because we are mainly concerned with protecting the JVM from native code.

there are situations where isolating one native library from another is desired (e.g., when napplets are downloaded from multiple websites that have di.ering trust levels).


[28] introduced ORP, a static rewriting tool which randomizes instructions and registers within a BBL to mitigate ROP attacks.

oRP cannot prevent return-into-libc attacks (which have shown to be Turing-complete [34]), since all functions remain at their original position.


as well as .i and thus we have a contradiction since we assumed a perfectly binding commitment scheme.

if Gi = Gb(1., f, .i), then essentially A has executed the protocol honestly.


RELATED WORK Several approaches [1][7][18][5][3][19] are proposed in the litera ture to study the problem of mining association rules in distributed and parallel manners, where the data is partitioned across several nodes.

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


For this reason, any security implementation will suffer from false positives.

a system administrator must weigh the benefits of blocking good traffic (false positive) versus allowing some bad traffic (false negatives) to determine how strictly to check data.


This roughly corresponds to an interesting downgrade of 29% of the overhead caused by metadata.

when calculated on the whole tra.c, the overall improvement is only of 0.66%.


Given the large attack surface of complex Objective-C based applications, the lack of system-wide sandbox functionality is cause for concern.

the Android platform is rated at high for system isolation.


Looking at the table s provenance analysis results, it appears that most of the vulnerabilities stem from the AOSP.

recall that our provenance analysis concerns the original provenance of each app, not each vulnerability.


Likewise, major changes to JavaScript itself are currently out-ofscope as we assume an off-the-shelf JavaScript environment.

the mathematical functions needed to roll your own cryptographic primitives such as modular arithmetic and native BigNum integer support in JavaScript is not feasible at this point, as these changes would impact the entire the entire JavaScript environment and thus are more properly standardized as part of JavaScript itself in ECMA TC 39.7 we provide a simple BigNum type de.nition in the Web Cryptography API, although we do not provide the underlying operations as native code.


If the arguments are supplied directly, we can simply register (and unregister) them at the call site.

if the arguments are passed from elsewhere, we must determine which functions they could have come from.


Secondly, the limited bandwidth for Internet access over cellular networks and the cost of GPRS/EDGE/3G access are barriers to the use smartphone users in an outdoor environment.

a smartphone user can still be lured into downloading .les such as Skulls and Doomboot, disguised as games, and end up getting infected by a smartphone virus.


Note that the graph obtained in this fashion is still a graph that could have been generated by 4.7.

this graph only has m = n nodes, and all nodes have received and forwarded a Key-Establishment-Query for nodes A and Y .


We note that static versions of some of these mechanisms can be implemented in TE, notably, Chinese Wall and Information Flow.

changes to the authorization state (con.guration) must be made by trusted system administrator, and are outside the scope of TE.


Removing B2 from the key fragments distribution would result in a lower overall key-vulnerability, as the event of S1 and S3 being compromised would not imply a compromised key (the attacker would only know subsets of B1 and B3).

removing B2 would also reduce key-availability since a legitimate user would not be able to retrieve the key anymore if S2 was not available.


Therefore in principle it is a good idea to combine both methods in the expectation of achieving better segmentation resistance that either can provide.

the implementation of this Megaupload CAPTCHA turns out to reduce such an expected  double insurance into an easily solvable problem: identifying shared white components and merging them with adjacent black components.


Although the proxy server does not handle the large dataset and process queries, it might still become a bottleneck for a large number of users and frequent query submissions.

the cost to scale the proxy server should be much lower than that to host the entire query processing service.


If the role is not in the intersection, then it is added to the set of activated roles.

as GEO-RBAC supports mutually exclusive roles, the algorithm must remove any con.icting roles that have previously been activated.


These two requirements may appear to be in contradiction with each other, since the .rst suggests that the server cannot learn any information until the protocol completes, whereas the second states that mistakes to recognize invalid feedbacks are aggregated.

this apparent contradiction can be resolved by the use of oblivious transfer techniques; these allow the client to index (using the credential pre.x) a database of feedback items that is unique to the user in question.


MOTIVATION The Internet presents a novel means of communication instant messaging (IM), where users can engage in active conversations across great distances.

iM lacks certain fundamental security properties that a physical private conversation can provide.


Fourth, the ad exchange invites the bidders, so it can manipulate auctions, by choice of bidders.

such manipulation is mostly limited (§5) to endowing a colluding bidder with a right of .rst refusal.2 Last, a malevolent publisher can deliver the auctioned ad to the wrong user; this issue concerns the authenticity of what is being auctioned and is a different problem from auction integrity, but we can limit abuse by publishers (§5).


The state variables that come from persistent objects can only be used by the application after they are retrieved from the database, thus can be observed from SQL responses.

the SQL response may contain a large amount of objects.


First, the goal of our problem is to authenticate the spectrum usage, i.e., to verify whether the primary user is indeed using a speci.c spectrum; we do not need to verify whether the contents sent by the primary user are authentic or not.

verifying the authenticity of the contents is exactly the objective of broadcast authentication.


On pages 5 and17 of his opinion, which is not published but which appears on the Public Citizen web site at http://www.citizen.org/documents/ dendrite.pdf, Judge MacKenzie appeared to apply a motion to dismiss standard in favor of these two defendants, inasmuch as he discussed the facts that Dendrite s complaint stated a cause of action for breach of the employment agreement, and that the message posts by Does 1 and 2 appeared to acknowledge their status as employees of Dendrite.

judge MacKenzie stated that he did not need to decide whether there was sufficient evidence that these two employees had actually signed the employment agreement that Dendrite was suing to enforce, id.


Similarly, when a VMM tries to copy data to a guest VM, the data is .rst written to the bouncebuffer and then readby theguestVM.

inprinciple,the.rst trap and emulate based approach canhandle bothport-basedI/Oanddirect memory access(DMA).it willintroduce alarge amount oftraps(i.e.,VM exits)toCloudVisor if thedatais copiedin small chunks(e.g.,4 or8bytes).


FOAF provides various classes and properties to describe social network data such as basic personal information, online account, projects, groups, documents and images.

these basic mechanisms are not enough to capture all the available information.


In most cases, the function has a value of 1 when an attack occurs and a value of 0 when there is no malicious activity.

other, more complex models could be used (e.g., the type of attack could be taken into account).


This results in a disconnectedness of today s models.

this combination is required by multimedia applications that integrate, e.g., image data and video data, in particular in the open world of the web.


The attack described in Figure 2 can be obviously applied.

there is a much simpler strategy for Eve to recover two shares at each round.


Once a reply is ready to be sent back, it is desired that the route back to the source is ready as well.

in ad hoc networks, the network topology can be changed dynamically and unexpectedly.


More precisely, MO-BIKE has been designed to handle tunnel mobility, which is perfectly convenient for the OAA.

oSA has designed for a dedicated service which makes possible end-to-end security.


There exist many other anonymous authentication protocols for RFIDs, see for example [9, 10, 31].

they either provide privacy against only unauthorized readers and eavesdroppers, or cannot be directly applied to our privacypreserving e-ticketing system that supports monthly billing.


We can conclude that users who employ random passwords are less susceptible to keyboard acoustic attacks than those who employ weak passwords.

our attacks on random passwords are still orders of magnitude more successful than random guessing or brute-forcing attempts.


Each of the above application scenarios makes use of digital credentials and other, more subjective, horizontal trust metrics during the decision making process.

despite their similarities, these scenarios also di.er from one another in very signi.cant ways.


Hence, to make scheme more securer and work continuously, a large t and a corresponding large group size are desired.

we can not arbitrarily choose a large group size.


Ideally, SMMDumper could just read memory one byte at a time and send it o. over the network.

this would hardly represent a reliable solution.


IC products from untrusted foundries must be fully tested to ensure that no malicious alterations have been made.

due to the consequences of deep submicron technologies, process variation (PV) [2] becomes an unavoidable component in the manifestation and physical properties of ICs.


SessionLock does not prevent against active attacks, but prevents session hijacking and thus incapacitates tools such as Firesheep.

an active attacker can easily alter the client s behavior by modifying a response to contain different JavaScript, which can then be used to either leak the session key or make use of the compromised client to construct signed messages.


Physical Protection of the Recovery System The physical protection of current sensor node platforms is very poor because of their focus on simple maintenance [9].

although it is generally agreed that entirely tamper-proof sensor nodes would be too expensive, current trends in the hardware development of embedded devices indicate that some level of physical protection will be available in the near future [20, 15].


This doesn t restrict the power of the protocol: after executing outA, outB the parties can send 0 as many times as needed, ignoring any received messages.

the channel is potentially stronger, as it is allowed a higher proportion of errors for transcripts that prematurely terminate (if any exists).


The reason is that relatively few absent sets need to be considered.

for larger values of n (say, n = 90), increasing d has a pronounced effect on the running time.


a clear separation of genuine and imposter distributions.

the effect of compromised transformation keys on authentication accuracy has not been tested rigorously.


Then one may ask whether it is possible to incentivize a veri.able computation that preserves input/output privacy of D. Indeed in the full version of our paper, we show somewhat surprisingly it is possible to incentivize veri.able computation schemes with designated veri.er (i.e., in contrast to public veri.cation).


To all presented recovery measures applies that they are only applicable if at least the therefore needed systems of the corrupt node still work correctly.

although it is generally agreed that entirely tamper-proof sensor nodes are too expensive, current trends in the hardware development of embedded devices indicate that at least some logical and physical protection (e.g., CPUs which support isolated memory areas or automatic memory erason if a node is tempered with) will be available in the near future.


This is an obvious trade-off in using out-of-band command and control in contrast to the traditional channels the former provide better undetectability while the latter possess better bandwidths.

even with low bandwidth, the envisioned audio channels can de.nitely be used to rapidly send triggers to a large number of devices.


The Push Method o.ers a less complex protocol .ow and is compliant to the SAML standard.

a suitable browser extension is required, which recognizes the type of the  and pushes the required information to the eID-C.


Program Execution [6] is one of the remote attestation techniques that measures the information .ow of system calls generated by an application and compute a hash of these system calls, which can be reported to a remote party for veri.cation.

in our opinion, there are some limitations to this approach that keep it being deployed in real world.


The Linux ptrace implementation requires us to perform a system call once a system call has been initiated by a program variant.

if the system call is executed only by the monitor, the variants must skip the call.


Compared to these three method [17, 22, 23] the method proposed in the Image Spam Hunter utilizes probabilistic boosted tree, which is much faster that SVM used in earlier methods [17, 18].

the authors themselves point out that some of the weaknesses of their method includes inaccurate detection if image contains scanned documents or real life photos.


This heuristic enables legacy applications to run with XnR protection.

programs that are available in source can be forced to store all data in a separate region, similar to Linux programs with a modi.ed linker script.


In this regard, their attributes are valuable so that the medical emergency agents can be prepared or make arrangements with a medical clinic.

because of the criticality and importance of attributes such as HIV, it is necessary that only authorized medical personnel learn about them.


In this work, one unit of watermark is the ASCII code representing a character, which is embedded in one unit of the cover medium, the binary image of a segmented character.

embedding the code of a character onto itself does not allow its recovery if tampered.


Hence, there is space to remember the following number of requests: oi-1 2j-1 q + j=1 q +2i-1 q =2i q.

ti is replaced with a new table every 2i q requests.


A variant of this question was tackled by parameterized expressiveness [11], which evaluates an access control system s qualitative suitability to an application by assessing the strength of the security guarantees that it can satisfy while operating within that application.

this type of suitability analysis provides no quantitative guidance in choosing the best access control solution for an applications.


To determine which users have the authority to resolve a miscon.guration, we could analyze the implemented accesscontrol policy.

the language for expressing policy varies widelybetween systems, and we wish todesign a techniquethatis not speci.c to anyparticularlanguage.


Low load values mean that the number of simultaneous service sessions is lower than the number of available VIDs.

for high load situations (11) converges to NV ID, i.e.


This made Xen very popular because it has the advantage of providing good performance and the ability to run virtual machines on top of non-virtualized architectures such as x86 [9].

the disadvantage of paravirtualization is that guest operating systems must be modified, which becomes difficult if not impossible with closed source operating systems such as Windows.


The real encryption rate of this cryptosystem is relatively small, but if the elements of this small random sequence are set to 0, the rate can be slightly increased.

the pseudo encryption rate is estimated with the concatenated vector of the random sequence and the message vector.


Similarly, identical values for an IP Address refer to the same network device, local addressing and NAT notwithstanding.

size and CPU usage for instance are not categorical: identical values may refer to di.erent realities while similar events may be logged with di.erent CPU usage and size values.


Unless P = NP, there is no polynomial-time algorithm for producing the core of a given arbitrary structure.

in our case of interest, namely data exchange, we give natural conditions where there are polynomialtime algorithms for computing the core of universal solutions.


Using NFC antennas, a device can harvest energy from the RF .eld generated by NFC initiators within close proximity (a few centimeters).

the amount of energy that can be harvested during the probing is usually very limited, as NFC radios have a low duty-cycle (10%) during the probing phase.


The plugin mechanism provides a convenient way to extend an application s functionality.

it may also introduce susceptibility to new security issues.


Satisfying these assumptions in practice could be di.cult considering current compliance failures (e.g., [10]).

this technique is apparently easyforIDissuingparties toimplement(i.e.


In a two-party interaction, say an interaction between Bob and Alice, it is not enough to consider Alice s trust in Bob; Bob s trust in Alice must be considered as well.

in some situations we might consider on party s trust explicitly, and another party s trust implicitly.


The threats mentioned in previous works are mostly advanced attacks against TCP/IP protocols (e.g., TCP SYN .ood or injecting malformed TCP packets) and well-known malware targeting the network.

according to our empirical observations, a weakness of predictable TCP ISN generation remains in devices in the power grid network.


Finally the ATiki system was helpful in producing a report on the identified vulnerabilities: Parts of the attack net graph were quite useful for the presentation and visu-.lization of vulnerabilities ~nd their causes.

attack net graphs can easily grow to a size that does not fit onto paper.


Previously, BLP seemed much more feasible than RBAC due to the latter s managing a very large number of roles.

considering extension state reveals a di.erent scenario.


Intuitively, for the real system, partition g is in control when its program counter points to a location in memg.


One may ar gue that if askfacl is always use to manage an ACL, then the redundancy should not matter.

it may be desirable to maintain an ACL without such redundancy in case an administrator chooses to view or edit the underlying ACL directly using get/setfacl.


New functionalities like those of SBC (Session Border Controler) partially solve these issues.

often the same session policy is applied for all users and this may prove unacceptable regarding the user s requirements.


We define a threshold.which triggers the update of the screen: the screen is updated only if the number of received nodes is larger than .. Generally the bigger the ., the less the total time of transmission.

the interval time of displaying different resolution graphics will increase.


The network scale of the EigenRep model is less and the average path length is short.

the average path length increases with the network scale increases, consequently the total hops of the messages increases fast.


If the secret contains both types of quotes, or the attacker cannot predict which type of quotes it will contain, the attack may fail.

unquoted url()s may contain unescaped quotes in Internet Explorer.


Section 4.3) or protect data assets in shared resources like System Content Providers.

the enforcement described in [27] and [7] is too coarse-grained.


The trusted and the untrusted parts of VPFS as well as trusted and untrusted applications need to be executed in di.erent protection domains (i.e., isolated tasks on a microkernel and legacy VMs).

the isolation must be breached such that the two parts of VPFS are still able to communicate with each other.


One obvious way to represent this information is as an average, e.g., the average frequency with which a transition is taken.

it is well-known that network phenomena tend to be highly bursty, and hence averages do not provide an adequate way to characterize such phenomena.


Therefore, it is necessary to rely on certain protected environment to achieve this security objective.

a fully protected environment may be dif.cult to establish in practice, which requires to protect all messages delivered between user and server.


From t = 190 min until t = 360 min, we (the adversaryin this case) continue the deception attack resulting in open-loop response of actual water level, The recovery period lasts from t = 360 min to t = 510 min using the same recovery action as in the case of simulation experiment described above.

a residual error still remains after the end of recovery period (which is also the end of attack) and the PI controller reacts to this error.


Introducing memory protection further hardens the system against code-injection attacks, but incurs a substantial overhead.

forcing an attacker to exploit a vulnerability in this fashion is already hardening the system considerably, as he would have to somehow discover one of the few memory locations which can be used to divert PIN s control .ow.


Pub/sub is an open communication model with the implicit assumption that the interconnected brokers are trusted with events and .lters con.dentiality.

it is very likely that brokers could be deployed on an outsourced infrastructure.


[6] designed a mobile botnet called Andbot 10 Di.erent international exit codes are used to di.erentiate calls tothese numbers, e.g.,011forMontserrat,001forThailand, and 00 for New Zealand.

such exit codes are often attached automatically by the device without informing the user.


The de.nition of a role concept (role engineering) is a di.cult task traditionally performed via interviews and workshops.

often users already have the permissions that they need to do their jobs, and roles can be derived from these permission assignments using data mining technology, thus giving the process of role concept de.nition a head-start.


Therefore, we would argue that, in many practical situations, the most appropriate approach is to use .at RBAC+ to specify spatio-temporal requirements.

sT when there are very large numbers of user and permissions, it may well be appropriate to use role hierarchies, thereby avoiding large numbers of user-and permission-role assignments.


Swim reports to the user that it may not be possible to instrument the program to satisfy the policy, and as a programming aid, provides the subprogram and policy assertions that contributed to the unsatis.able core.

if the SMT solver .nds a solution to the bit-vector constraints, then Swim translates this to a solution for the system of set constraints.


Similarly, the target user can be represented as an object property TargetUser between the Prohibition and Person classes, and the target object as an object property TargetObject between the Prohibition and the Resource classes.

the privilege over which the supervisor is authorized to state .ltering policies is not represented as an object property.


One obvious solution is to disable such features in Windows.

many users find such features a convenient and productive way to conduct their business.


Those events occur very early at an average of 8.5 to 10.5 observed events.

the top 5 decreases in Figure 6(b) occur quite late and represent the features indicating the actual attack.


Such mechanisms are of special interest in the Bring Your Own Device (BYOD) context where employees integrate their personal devices into the company s infrastructure.

based on the leaking sensor information, an unprivileged application running in the private world of the smartphone might gain knowledge of sensitive information entered in the business world.


It is possible to extend SPM to only disclose the presence of a contiguous substring in a string at a speci.c location, e.g., by modifying parties inputs from a sequence of letters to a sequence of hash(letter||position).

there is no straightforward way to adapt SPM to match non-contiguous substrings, except for surrounding the pattern with single-character wild cards, which (as noted earlier) considerably increases protocol complexity.


The BA problem has been studied extensively over the past three decades and tight bounds have been established on resilience, round complexity and communication complexity for several variants of the probleminsynchronoussettings(see[13]).

verylittle attentionhasbeenpaidindesigningfast, communicationef.cient, optimally resilient ABA protocol.


Note the push instruction is used to save the return index onto the stack and the .rst jmp will jump to the target destination.

the compiler will consider the second jmp as unreachable, thus removing it as a part of optimization.


From the .gure we can see that most of the time, our monitor can separate different packets from each other.

there are situations in which only the cumulative length of multiple packets is identi.ed (see the markers in the .gure).


They propose protecting it with mprotect() like Return Address Defender, RAD [13].

as in the RAD case this will most probably impose a serious performance penalty.


[29] propose a spam detection approach involving user-feedback and semi-supervised clustering technique to differentiate between spam and legitimate calls.

the derivation of caller s reputation value requires building a social network; the notion of user s feedback requires modi.cation of SIP clients and an extension of SIP protocol [19].


Access for either or both protection modes can be granted to others as desired but may be revoked at any time.

beneath this simple interface, cryptographic mechanisms are used to enforce protection and this allows the scheme to provide enhanced security properties.


We also collect the website s Alexa rank, which indicates its popularity.

since the Alexa Top Sites service2 requires the domain name of a website, we have to map the Wooyun data to domain names.


We tried this attack against the standard version of [4] (in which a single watermark pattern is tiled over the whole image) and found it to be fairly ineffective at removing the watermark.

the possibility of this attack can be eliminated en- tirely by associating each key with a sequence of watermark patterns so that each segment belonging to one key contains a different watermark pattern.


Furthermore, we are required to enforce a TDMA strategy which inherently reduces the bandwidth of the communication channel since an unused time-slot is wasted.

this solution enforces non-interference proven by GLIFT in this particular scenario and such overheads could likely be tolerated for such a strong guarantee.


More recent group signature schemes [9, 2, 30, 1] address the issue of removing users from the group altogether (membership revocation), in addition to anonymity revocation.

each of the anonymous credential, identity escrow, and group signature schemes mentioned above makes use of cryptographic secret keys which can be transferred to another users if desired.


The most detailed analysis can be found in [12].

some problems stated there are inherent in browser-based protocols.


Using the employee s working set to regulate .le accesses 1For this paper, we will assume that devices administered by the corporation are trusted, and that employee s personal devices are untrusted.

wSBAC is independent of this assumption and will work with any technique that can be used to di.erentiate between trusted and untrusted devices, e.g., devices equipped with TPM hardware and integrity measurement tools [26] could be considered trusted.


In the multi-core mode, the host core cannot access the registers, MSRs and APIC of the isolated core.

the host core can still modify system-wide con.gurations that rely on shared resources (e.g., the memory control hub and the IO control hub).


Besides, in centralized scheme, VMs of an application can only be deployed within a same cluster to reduce the broadcast domain.

in RepCloud, an application can scattered among clusters, while remaining a low level of dissemination overhead, as tickets are disseminated according to nodes communication patterns.


If B chooses to send payment, he may observe con.rmation of payment, and later the reception of the auctioned item.

it may also be the case that B doesn t observe the con.rmation within a certain time-frame (the likely scenario being that the seller is a fraud).


4.2 Real Identities versus Pseudonyms The two European networks, La Ruche and Qype, do not oblige their users to register with their real identities.

foursquare asked in its terms of use that users should provide Foursquare with accurate, truthful, and complete registration information (including, but not limited to your name ( User Name ), e-mail address and a password you will use to access the Service) and to keep your registration information accurate and up-to-date .


Note that in the basic model, the authority could add users at any time.

in the revised model, he will also be able to revoke existing members credentials.


The initiator UA outputs XA on activation, then may receive an incoming message of the forms (I, I, UA, UB, XA, XB) from the responder UB, then computes the session key SK if UA received the message.

the responder UB outputs XB, and computes the session key SK.


INTRODUCTION There has been growing interest in usable security over the last decade, and numerous studies have been conducted to explore the usability issue of various computer security mechanisms [8, 19, 21, 22].

bridging the gap between security and usability is a challenging task.


To this end, the number of packets received has close numerical figures and similar trends as the energy consumption does.

node 6 has shown similar energy consumption in both orientations except under 10% score values.


Using PIR to protect client location offers strong cryptographic guarantees on privacy that SybilQuery unfortunately cannot offer.

the PIR-based scheme suffers from two drawbacks that limit its applicability.


3 Hardware-Only Redundancy Techniques Error correcting codes (ECC) and parity bits have been widely used to protect various hardware structures at a very .ne granularity.

it is tedious and impractical to protect all pieces of hardware logic with ECC or parity bits.


In Figure 4 (a), the edge E1 and E2 are occluded with oval, and perceived as a continuous shape under theirs.

figure 4 (b) cannot be perceived as a continuous shape.


Sensors have to know the location of the sinks or the rendezvous points in this approach.

this mechanism allows the adversary to locate and attack the sink easily.


By our assumption this implies s = r z .

for this ciphertext to be valid, it is necessary that: l z l z Cj,0 = E.EncPKj,0 ([fz]j,0,r j,0; H([fz]j,0,r j,0,s)) z since rj,0 has not been queried as a component in H, the argument for H has not yet been queried and therefore the above will hold with only negligible probability by the guarantee of unpredictable ciphertexts for E. Notice that if there is no overlapping valid ciphertext we can simply use the queries to the hash function to decrypt.


However, a variant involving only displayed sentences could be used.

this would represent overkill, since numeric comparison (as discussed below) is a better and simpler choice.


Aside from 3.8% of mouse movements with e.ciency less than 0.02 (most of which are zero e.ciency moves, due to the cursor being placed back to the origin), a bot rarely moves the mouse with other e.ciencies.

for human players, the observed probability of mouse movement e.ciency follows an exponential distribution.


On one hand, one starts from a correctly encoded state.

the errors introduced by the environment will be independent of the encoded data (and in fact they must be for error correction to be possible at all in that context).


If it meets Invariant 1, ((struct socket alloc)(cb)).socket will be the desired socket data structure.

if DeepScanner already have a process descriptor list, it can easily enumerate all socket data structures via traversing the .les .eld of each task struct data structure according to Invariant 3.


ANONYMITY AGAINST MALICIOUS DESTINATION The Comp-N-anonymity de.nition of the previous section covers the following attackers: eavesdroppers, malicious peers, and any combination of them that controls the application adaptively.

due to the restrictions of the RH N relation, the de.nition cannot be used for testing anonymity properties when the attacker controls destinations of messages from honest peers.


as described in the previous example, D can infer the compromising trace (?g, ?u, !o, !r) based on observation h = (?u, !o).

there also exists a behavior alternative b ..(PM,S)that hides R wrt.


An ideal PUF behaves like a memory programmed with a random number.

to date no PUF structure is known that provides perfect reliability and randomness at the same time.


In our experiments, we set the weights as wsp = wsu = wsh = 31 .

they could be adjusted based on the system and application requirements.


It is shown that if an RFID system has strong (or weak) unpprivacy then the computational power of an RFID tag can be used to construct a pseudorandom function family provided that the RFID system is complete and sound.

if each tag is able to compute a pseudorandom function, then the tags can be used to construct an RFID system with strong (or weak) unp-privacy.


We previously showed that the base algorithm was resistant to training with contaminated tra.c, where the tuning parameters can be adjusted to compensate for the statistical spread caused by contamination.

this tuning requires lots of repetitive computation.


VirusTotal is the only initiative in this direction.

as stated by the maintainers themselves, VirusTotal does not use the original products: It uses command-line versions of the applications (instead of the GUI based ones) along with the same signature database shipped and updated by the vendor.


Although very effective against jump-into-libc attacks, it is less so against other common attacks, due to the fact that the amount of possible randomization is relatively small (especially when compared to our key sizes).

address obfuscation can protect against attacks that aim to corrupt variables or other data.


{D.Quercia, S.Hailes, L.Capra}@cs.ucl.ac.uk ABSTRACT To share services, portable devices may need to locate reputable in-range providers and, to do so, they may exchange ratings with each other.

providers may well tweak ratings to their own advantage.


(d) If the required claims include attributes other than the PPID claim, then the plug-in terminates, giving CardSpace the opportunity to operate normally.

if only the PPID claim is requested, then the plug-in adds the city and web page claims to the requiredClaims tag, marking them as mandatory (see section 3.2.3).


When the sender domain has a larger weight, the sender has too large an e.ect on execution times of processes running in the receiver s domain; speci.cally, the receiver process is likely to miss a communication request.

in the current protocol, the receiver recognizes a communication request when the period of high CPU load lasts for about 1.5 s. a receiver running in a domain with an extremely small weight may consider that the high CPU load lasts for more than 1.5 seconds, and consequently, it may miss the communication request.


A node must have received all packets in pages C1, ..., Ck-1 before it can accept packets from page Ck.

within page Ck,the NACK-based design allows out-of-order arrival.


In this particular example, the effect of the modi.cation operation is similar to the hiding operation.

depending upon the renaming used, it is possible to modify an ontology as required.


Mention must also be made of Capability Maturity Models (CMMs) that provide a reference model of mature practices for specified engineering disciplines.

they define process characteristics instead of the processes themselves and therefore tend to define the what and not the how .


In general, active covert timing channels are faster, but passive covert timing channels are more di.cult to detect.

active covert timing channels often require a compromised machine, whereas passive covert timing channels, if creatively positioned, do not.


Nowadays, most internet resources are identified by ASCII based Uniform Resource Identifiers (URIs) [4].

uRIs are cumbersome and inefficient for people speaking languages other than English.


Hence, PTF can provide valuable comprehensive feedback to users.

feedback from TISs is not comprehensive (only partial).


Role names are usually defined by the applications that adopt them and they have no explicit formal structure.

it will be practical in many cases to qualify role names with a code publisher name or some other global qualification so as to avoid naming conflicts.


Context Framework: We are currently in the process of creating a context inferencing framework on the mobile phone.

in this work, for evaluating risk, we have usedthereality miningdataset[5] forderiving ourcontext stream.


These failures have made clear the fragility of the trust model and revocation mechanisms in the web space, and have inspired the community to examine methods both for reinforcing the system s mechanisms to prevent fraudulent certi.cate issuances and improving the robustness of the revocation infrastructure.

there is considerable debate in the community regarding what the appropriate metrics for judging replacement systems should be, and how the di.erent proposals compare under realistic conditions.


Thus, they do not provide a fully distributed key management.

deng and Agrawal [7] propose a mechanism to secure the Dynamic Source Routing (DSR) protocol for ad-hoc networks in which the trusted authority is fully eliminated by the utilization of IBC along with threshold secret sharing.


Thus the PGD contents regarding the speci.c target ob ject s virtual address could be previously de.ned, which creates a semantic invariant.

to mitigate Memory-bound ATRA, the external monitor should, in fact, check the integrity of additional data structures that are subject to the race condition (we will discuss this in the following paragraph).


It is possible to bring VM images online, apply patches, and capture the VMs back to dormant images.

such approaches suffer from unpredictability, performance challenges, and high operational costs, particularly in large-scale compute clouds where there could be thousands of dormant VM images.


We note here that GHASH is claimed to have the ability to be computed incrementally, which makes GHASH a candidate for being used in our scheme.

the incremental updating of GHASH requires power operations in GF.


We pointed to various methods for quantifying the risk associated with authorization policies.


SecVisor [27] protectskernel code from modi.cation thus defeating certain attacks.

merely protecting code segments is insuf.cient to guarantee correctkernel operation, as shown by return-to-libc [30] and return-oriented programming [17, 28] attacks that make use of unmodi.ed, non-malicious code to accomplish malicious goals.


We use this con.guration because it is a typical vulnerable environment for web browsing.

in theory our prototype can also be integrated with other MSIE versions on di.erent Windows versions.


We believe that our approach is signi.cantly easier to adopt than the formalism-based approaches which often require complex proofs every time the policy is changed even slightly.

a measurement-based approach needs to ensure that we are comprehensively measuring indicators for compliance, and there is no formal proof that this is indeed the case.


Intuitively, c can purchase the .ltering service from all the f -providers to maximize its bene.t.

as shown in Figure 1, since a spoo.ng .ow can be .ltered by multiple f -providers, purchasing the service from all the f -providers implies that c pays for .ltering a same .ow for more than once, and c wants to keep this redundant payment rate under a threshold µ.


This policy is very clear, and informs employees that anything they create can be monitored by the company.

medical World rarely enforced this policy, and the court found that the lack of enforcement gave Curto a reasonable expectation of privacy.


MultiplyMatrices([D ' ]pk, f[C]pk); [D '' 3: return ]pk; Computing the inverse of an encrypted matrix is an extremely complex operation.

observing that a permutation matrix is an orthogonal matrix by de.nition, and therefore special properties apply, i.e.


UPPER BOUNDS 4.1 Window Sum A key observation for computing window sums with error polylogarithmically bounded in W is that, unlike with running sum, only the lowest log W + 1 layers of the dyadic tree are necessary to compute window sum.

if we keep a dyadic tree for every window of size W , each update will contribute to more than W variables, resulting in data structures with large sensitivity, which, for di.erential privacy, translates into more noise.


One attractive higher abstraction level is the system call level, and nice system call level dependency analysis mechanisms are proposed in such works as [11] and [8].

system call level analysis cannot satisfy all the .ne-grained damage assessment requirements.


Since packet headers may be modi.ed by compromised routers, not all AP fragments are observable.

we know the last OAF which ends at the victim must be observable based on the de.nition of an OAF .


introduced Timeweave [27] that uses a time entanglement mechanism to preserve the history state of distributed systems in a tamper-evident manner.

timeweave does not handle the information .ows synchronized which is required in optimistic replication where concurrent operations appear in different orders in replicas.


INTRODUCTION Statistical data analysis is an essential task in many data mining and business intelligence applications [10].

when the data come from multiple parties and where user privacy is a big concern, we need to perform the data analysis task in a privacypreserving manner.


When the policy prohibits an application from accessing the network, the interceptor simply denies such access.

when the policy prohibits an application from accessing the sensor, there are two simple options for enforcement.


Use of a training section should enhance memorability, but will make enrollment far more time-consuming.

the ease of recognition for familiar tunes might make training unnecessary.


This example provides strong evidence that analyzing implementations rather than algorithmic descriptions can lead to the discovery of interesting attacks.

it also highlights a number of di.culties with this approach: 1. the number of faulted implementations grows at least exponentially in the length of the original program, in particular if multiple faults are considered; 2. some fault attacks require to tamper with some (but not all) loop iterations, or to add or remove some loop iterations; hence, the number of faulted implementations cannot be bounded solely based on the length of the program; 3. analyzing the e.ects of faults becomes very involved and error-prone, in particular for programs with loops; 4. there exist multiple implementations of basic arithmetic operations, requiring to repeat the analysis for each; 5. there might exist numerous countermeasures against a fault attack, requiring to repeat the analysis for each of the protected implementations.


The setjmp()/longjmp()-mechanism prohibits instrumentation in the app itself.

under the term Zero-Cost Exception (Itanium-ABI and 64-Bit Mac OS X) [6] and SafeSEH (Windows) [34] another mechanism is used, which stores the catch locations in a constant table.


Nonetheless we .nd that the number of iterations is reasonable in practice (see Section 5).

the parallel cuckoo hash would not be a good choice for buildinga large hash table ona GPU, since each iterationwould require shuf.ing items in global memory with global synchronization at each iteration.Butitisvery useful for tables which canbe com- Algorithm 1 Basic hash table implementation Phase1: Distribute intobucketsof size = 512 1: compute numberofbuckets required 2: allocate output space andworkingbuffers 3: for each k .


Moreover, the useof cryptographyallows CloudVisor to provide strong guarantees on client VM security and privacy.

sSC o.ers three concrete advantages over CloudVisor.


3.3 Security Requirements In our framework, we are concerned with the security risks from data users or service providers as follows: Data users: In our framework, the malicious users cannot observe the encrypted data stored in outsourced storages, thus they cannot directly attack to the ciphertext header H.. .

the malicious users could try to make use of the Delegate algorithm to access .les.


As a result, applications compiled for this architecture are more resilient against normal input string exploits.

for deeply-nested function calls, the kernel will have to perform a register window switch, which involves saving some of the registers onto the stack.


Ifakernel executionmode(orexecution rings) were available, those features could be implemented safely.

they cannot be implemented without major changes to the AVR core without the presence of such a privileged mode.


Such kinds of kernel memory scanning tools have been proposed by some researchers [3][8][9][21][23].

the signatures used by these tools are almost brittle and non-essential that making them easy to be evaded, even by simply modifying some bits of the data structure without preventing the entity from working correctly [24].


Considering the statisticaldataoutsourcing primitive we have discussed, in order to prevent disclosureofdatadynamics,oneapproachisto estimatethe datachangeratethrough theperturbedstatisticaldata that are deployed at the data resource.

updating the deployed data too often increases the amount of noise that need to be added to the synopsis.


One deep implication for PKI of identity plurality is that it inverts the expectation that closed PKI is a compromise while open PKI is the proper long term goal.

we should now appreciate that open PKI would be a special and highly theoretical instance.


We are motivated by prior work that demonstrated that a placement of mediators that resolves all information .ow errors is equivalent to a cut of error paths in the data .ow graph [37, 19].

to make this idea practical, we explore how to produce an information .ow policy for the example web application that resolves its local and remote threats.


Only then do they proceed with duress detection.

unlike existing authentication schemes, our schemes are also required to preserve the stealth property (defined in section 3.5).


In Algorithm1,thePEP needstowaitforallobligationstomove beyond the pre-decision stage to make the .nal decision.

it is possible that one obligation refuses to moveon.


The feasibility of applying keystroke dynamics veri.cation to mobile devices has been .rst analyzed in [16] with a neural networks-based approach, which has been further extended in [17] by analyzing the feed-forward multi-layered perceptron network, the radial basis function network and the generalized regression neural network.

mobile devises may lack the computing power necessary to employ a neural network-based processing on the device itself [18].


The application of formal methods to cryptography has a long and rich history.

much of the the work in this area has focused on the formal veri.cation of cryptographic protocols in the symbolic model, which assumes that the underlying primitives are perfectly secure.


Symmetric cryptography primitives such as Message Authentication Codes (MACs) are computationally ef.cient and therefore are preferred for resource-constrained devices in small-scale systems.

such primitives are not scalable for large-distributed systems and are not publicly veri.able [13, 27].


In the absence of any background information on y1, this results in an entropy loss of one bit; equivalently the value of x is half the value of y1.

if the recipient were to know that y1 = 0, then there is no loss of information.


The compromised users do not know which random friends are selected by the application, and hence cannot exactly match data to users.

this approach hurts application functionality: To protect user privacy, a signi.cant amount of data cannot be shared between friends.


Figure 1: Architecture of TruWallet proach reduces the amount of needed TCB code.

when the trusted code is executed, the remaining system code (the operating system, browser, etc.)


As mentioned, SSH-IPC is susceptible to an adaptive chosen-plaintext attack requiring an SSH user to encrypt on the order of 213 packets.

the attack may not be considered practical since it requires the attacker to, after seeing a ciphertext collision, control the next message that a user encrypts.


When a user attempts to schedule an action for some future time, this should only be allowed if the action will be allowed at the time it is being scheduled.

a system which operates in this manner runs into a potential problem with information leakage.


On the other hand, SHELF coordinates system-wide damage tracking and quarantine operations to precisely determine and quarantine malicious and infected objects in the system quickly after the intrusion symptoms are detected.

uninfected applications could keep running with caution during the recovery procedure and uninfected .les can be properly accessed.


The latest research efforts [7, 8, 17, 25, 26, 30] assume regex can provide enough accuracy and focus on increasing its speed while reducing the memory occupation.

their assumption regexes can provide enough accuracy is questionable.


Encounter keys x and y hash to the same value, leading the server to relay Ex(m) to participants in both encounters.

only participants with key x can recover message m. A timestamp t nonce in the reply prevents replay attacks.


All OWL descriptions are shrink restricted.

roles that are neither shrink restricted nor growth restricted can be handled by simply dropping all RT statements de.ning them.


From a logical point of view, TVDs are isolated (virtual) computer networks.

their physical deployment can span over several computing platforms.


Theygive intuitivediscussions about why deciding strong accountability in presence of cascading obligation is di.cult.

they did not present any theoretical results regarding this.


Several of the schemes for countering SMS spam proposed to date use some sort of a text classi.cation method based on machine learning.

in order for such techniques to be e.ective, they .rst need to be trained by processing a substantial amount of text messages, before they can successfully classify messages.


3Our system can easily realize a check of the terminal s attribute policy and restrict the disclosable attributes for uncerti.ed terminals.

these proposals do not constitute a real solution of the problem at hand, and further research is required in this area.


These techniques can help detect some vulnerable IPC usages, which we show in our study still widely exist in popular apps and mobile-cloud services.

we are not aware of any prior effort to secure the end-to-end communication between an app and its server across the underlying mobile cloud service, which can have those known vulnerabilities and the new ones found in our research, and is beyond the control of app developers who need to use it.


Signature permissions protect particularly dangerous functionality.

there is a tradeoff when deciding if permission should be dangerous or signature.


Virtual instances have the bene.ts of being low-cost, easy to automate and generally .exible.

virtual devices are not typically used in everyday computing, so malware that can detect the virtual environment may elect to exhibit alternate behavior.


This is the first work on honeywords for graphical passwords, whereas all previous methods are only for generating text honeywords and thus inapplicable.

we use the IPM model to develop the first successful dictionary attacks on Persuasive Cued Click Points (PCCP), which is the state-of-the-art click-based graphical password scheme and robust to all prior dictionary attacks.


With regard to DNS overhead, note that spatial mutation causes a marginal overhead on the number of issued DNS queries in the network.

temporal mutation results in renewal of eIP mappings forcing all clients to query the authoritative DNS of the network.


After clearing them, we can still access a remote server correctly via the SSH connection.

ops, fasync list, .le, sk, and wait .elds meet the second requirement but not the .rst.


Unlike the impossibility result for general composition, this lower bound leaves open the possibility of obtaining positive results.

it does show that even in this rather weak setting of concurrency, obtaining security is "difficult".


One alternativeistoadda .eldfor the LPID in page table entries and TLB entries.

this approach signi.cantly increases the page table and TLB size, which is detrimental to system performance.


@write) which grants read access to ted logged in by any authenticator and subsequently running any application.

write permission is controlled differently and is allowed only to ted when authenticated by the login application.


Encryption is one way which may ensure the content security and prevent an unauthorized access [2] .

once users receive and decrypt the data, the content could be copied and redistributed at their option.


Ventana [20] is a virtualization-aware .le system that stores VM images and enables .ne-grained sharing of VM images.

it does not support .ltering and maintenance of VM images as done by the Mirage repository.


For example, if an aggregate operation computes the maximum timestamp of three input tuples in levels [., A], [., B] and [., C], the output tuple is in level [., T ].


This is, obviously, ideal for the owner, since her/his privacy risk and sharing loss are both equal to 0.

the privacy risk and the sharing loss are large for every non-owner controller.


Even if persistence is achieved, the cloud computing environment will be minimized with only the data and programs necessary to carry out the required computation, and so will likely be of low value to the attacker.2 In order to escape to the high-value client environment, the attacker must compromise the channel between the client and the cloud.

the defender has the .exibility to shape the channel s attack surface to make it more defensible.


The total number of vulnerability reports per month increased from 92 in July 2010 to 512 in December 2013.

the peak number of vulnerability reports per month is 959, which occurred in July 2013.


The di.erence between art and engineering is that the artist is free to choose objectives and approaches, whereas the engineer needs to understand and solve particular problems.

humans have a funny knack for .guring out how to do something when there is no perfect answer.


So, the threshold di.ers from dataset to dataset for the best results.

a most probable range of t values for the three non-network datasets covered is shown with vertically drawn dashed lines in the Figure 2.


It also supports the integrity of a VMM including access control modules as it detects any alternation of the VMM at boot time.

there have been fewer efforts in virtualization security for mobile devices that guarantee availability against Denial of Service (DoS) attacks from malware considering that mobile devices have limited system resources.


Our system call model should therefore prohibit system call behaviors speci.c to the disabled features.

an attacker could try to restrict herself to a minimal system call model.


The Uniform model, again as expected, tends to overestimate the Entropy.

for the R´enyi Entropy both models and the data seem to give results that are close together.


Whenever a global violation is detected the centralized enforcer will stop all the jobs executing in the domain and reset the global security state of the system.

centralized enforcement in large scale systems is not scalable.


That is, the session-key computation of T-KEA takes about 2.2 exponentiations, which is, however, still in sharp contrast to the about 1.27 exponentiations of (H)MQV in such a scenario.

the sessionkey derivation of (H)MQV is less .exible than KEA, in the sense that we do not know how to remove the value g ab from the session-key computation of HMQV for applications where HP-deniability takes priority, while still preserving its provable security.


Because a subset of residue object bugs result in cross-domain accesses, these defense techniques are good mitigations for such bugs.

they are not designed to mitigate other types of residue object bugs.


The original authors of the attack proposed Locked SOP (details in Section 7.4) for mitigation so that the malicious JS, even if it reached the browser, fails to sniff at any legitimate content.

sOP implementation is known to be problematic [17].


Notice that for the protected entity e2, X1 contains only one blocker of e2 and hence, T1 is not K-safe.

the set T2 can be written as D -X2, where X2 = {t2,t4}.


Therefore, after the secret update protocol, Sj can still iden- D tify/authenticate the tag based on ti.

sj has no D knowledge about si, which is known to the new owner Sj+1 only.


To deal with the delay in signature generation, and particularly to deal with the threat of fast spreading worms, several approaches [22, 17, 33, 26] have been developed to generate (worm) signatures from attack tra.c, including polymorphic worms [26].

all these approaches rely on other means to identify the attack tra.c.


Hence, a context that obtains the values for x and y cannot distinguish .0 and .1.

the context can discriminate .2 by testing the predicate f(x)= y.


The above analysis suggests that 2-bit of auxiliary memory per item is sufficient to realize deterministic and collision-free hash tables.

associating the n 2-bit discriminators to the n items in a one-to-one manner is a concern.


Therefore, for comparable throughput values, the hybrid approach will require the same or less proxy CPU time than a multiple processes con.guration As a tradeoff, the use of batch requests will increase the session setup time in low traf.c scenarios.

the delay introduced is unlikely to be noticed by humans.


In the case of FAF, as is standard in access control, can do is interpreted in terms of permission only; FAF does not take alternative interpretations of can into account.

alternative interpretations of can do are not only possible, but often need to be represented in access control models in order to capture domain-speci.c requirements.


So, all packets are broadcast to one hop neighbor of sender.

the communication between RSUs can be point to point.


This helps companies and Internet users to keep control over their data: By using an Identity Provider (IdP), they are able to enforce various access control strategies (e.g., RBAC) on data processed in the cloud.

idPs provide a valuable single point of attack: If the IdP can be compromised, all cloud services are a.ected, including well-protected applications such as Google Apps and Salesforce.


Therefore, relying solely on a top-down approach in most cases is not viable, although some case studies [19] indicate that it has been done successfully by some organizations (though at a high cost).

since organizations do not exist in a vacuum, the bottom-up approach utilizes the existing permission assignments to formulate roles.


These approaches can slow the running process signi.cantly, however, by an order of magnitude or more.

our vaccine mechanism tracks suspicious data.ow in a black-box fashion, which is signi.cantly faster than these gray-box approaches and still preserves much of their accuracy in cases we have explored.


The slowdown for integer computations ranges from 1.01x to 2.35x.

for .oating point computations the slowdown ranges from 1.00x to 1.64x.


facebook.katana , in which com.facebook.katana is the package name of Facebook app.

this origin is not easy to identify in practice, since there is no API to help us find out the initiator directly.


4.1 Cluster Prediction Table 2: Contribution of feature groups to cluster prediction accuracy for the 2010 dataset FORECAST is incremental and adapts with every sample that is analyzed, a dedicated training set is not strictly necessary.

it is still desirable to bootstrap the system on some initial data, so that predictions can be based on reasonable knowledge.


Electronic commerce, private and authenticated communication, and secure storage are but a few of the multitude of applications that rely on signatures to assert authenticity, ownership, or delegation.

signature-based systems are very vulnerable to the key exposure problem, which in practice is a far more likely cause of compromise than cryptanalysis.


Existing protocols for securing DHCP, such as CLL[12], can be used.

the presented TrueIP solution o.ers an elegant alternative to securekey distribution.


Most of them demand a strong confinement mechanism [7] from the TCB, and implement the TCB by using a virtual machine monitor.

the creation of a TCB using a virtual machine monitor leads to a decrease in usability, because of the coarse-grained access controls for resources.


In general it is well establishedfact that fusion helps to improve performance accuracy[11, 5, 13, 9].

our aim inthis paperisnot fusionpersebut rathertoinvestigatevarious aspects of performance improvement in the context of .ngerprint fusion.


Up to J « N staticjammer nodes, whose transmission ranges are uniformly R = ar where a> 1, are deployed within the network.

their positions cannot be known beforehand, except that all jammers are assumed to be sparsely deployedso that they canjam aslarge area aspossible.


There are a number of papers [5, 8] that outline alternative approaches to achieving adaptive and contextsensitiveaccess control.

more generic methods and techniques to handle practical problems within various access control scenarios are still highly desirable.


If subClass(v9)= v6 and subClass(v7)= v8, then we can merge the two by keeping only the more general attribute values as in as(4).

if subClass(v6)= v9 and subClass(v7)= v8, then we cannot merge the two because the attribute value pairs may represent two di.erent types of users who may be assigned to the role -one with a more general value for a6 and a more speci.c value for a7 and another with a more speci.c value for a6 and a more general value for a7.


Then, the server can directly authenticate the user without compromising anonymity.

another problem arises is how we can establish a secure channel (i.e., fowed data is encrypted).


Nevertheless, an additional challenge still remains: Even with knowledge of the target control system s behavior, an adversary cannot construct a payload for speci.c devices without knowing how the PLC interfaces with those devices.

there is often no direct way of determining which PLC memory locations regulate which devices.


However, it is very inef.cient for every sensor node to report their raw data back because every data packet need traverse many hops to reach the BS and especially sensor nodes are often constrained by scarce resources in memory, computation, communication, and battery.

as in many cases sensor nodes in an area detect the common phenomena, there is high redundancy in their raw data.


Note that the total number of susceptible nodes in the present model at time tis stochastically smaller than the total number of susceptible nodes in the above simple model at time t. Combined with Lemma 1, we get the following upper bound: n E[St] = (1 -av)t .


In long-lived encryption, such as for an encrypted .le in an archival storage system, the data is persistent and the key must be preserved for an inde.nite period of time.

an example of shortlived encryption would be a communication channel that is secured through the use of encryption and a key that is relevant only for the duration of the session.