Therefore, we relax our goal slightly and ask for approximate integrity : the adversary should have only a limited in.uence on the result of the aggregation computation.

if y denotes the result in the absence of an attacker and y .


have tried to solve the role mapping problem and activation checking problem separately [3].

they define the mapping of the request set PRQ to a role set RRQ within the context of the Inter-Domain Role Mapping (IDRM) Problem, associated with the aim of establishing inter-domain access policy mapping.


As for the other state-changes (creation and destruction of subjects and objects), the granularity is unimportant.

we can allow multiple subjects and objects to be created and destroyed simultaneously without affecting any of our contributions.


Some of these challenges stretch our current understanding of how information .ows in real systemsbut all of the challenges are tractable and can be addressed in future research.

we propose a relaxed static stability approach to DIFT where data is tagged with a .xed point number indicating a degree of taint, speci.cally the mutual information between the tagged data item and some tainted source.


S2: Set quanti.ed risk and bene.t adaptive policies:A QSBACenabled system will be policy-driven.

security administrators will preset QSBAC policies.


For any possible solution the program runs a utility in search of the local maximum.

for any given protocol, the program tries to .nd the best possible amongst similar protocols to that given.


Interviews with users revealed that many were using the intended recipient s ability to unseal a message as a proxy for recipient authentication.

subjects believed that only members of the campaign team would be able to unseal messages that had been properly sealed.


Our results suggest that our trained classi.ers are likely to outperform current measures of exploitability.

our classi.er outputs correlate much better with vulnerability outcomes than the Exploitability" component of the CVSS Base Score in eq.


We then calculate the similarity as the percentage of common n-grams out of the total unique n-grams.

the similarity of two classes ca and cb can be expressed as the Jaccard index of: |ca n cb | Si mil ar it y (ca ,cb )= (1) |ca .


A keyHolder simply contains the public key of a user for whom the associated grant is intended, speci.ed using the XML Signature standard [10].

the grant is awarded to whoever can demonstrate knowledge of the private key corresponding to the public key given in the contract.


For anomaly detection model, we are studying the effectiveness and scalability of our approach for building anomaly detection models for ad-hoc routing protocols and for other layers of wireless networking.

we will first focus on two questions about ad-hoc routing: what information a routing protocol should include to make intrusion detection effective, and what is the best anomaly detection model for a given routing protocol.


2 Preliminaries Throughout this paper, we will assume a Single Event Upset fault model.

we will assume that at most one bit can be .ipped at most once during a program s execution.


APPLICATIONS Blaze, Bleumer, and Strauss [5] suggested several interesting applications of proxy re-signatures relating to key management.We begin by taking a closer look at how proxy re-signatures can help relieve some of the common key management headaches.Next, we explore a broader set of applications and show that proxy re-signatures can be used to form weak (but easy to manage) group signatures, a spacee.cient proof that a certain path was taken in a graph (e.g., a packet followed a prescribed path through the network), and more.

4.1 Exploring BBS Key Management BBS [5] pointed out that proxy re-signatures can be used to change or add new public key pairs to a system without obtaining new certi.cates, notably simplifying key management.Let us explore this idea in more detail.


However, if the user moves slowly or stays in the same area, then instead of creating other redundant records, we may just increment the Duration of Stay field in the current record.

gPS coordinates close to the last sampled location are discarded.


Following the advice of Kempton [27], we do not evaluate models on the basis of correctness in terms of the reality of security threats home computer users face, but rather on the potential bene.ts that could be attained from behaviors that stem from the models regardless of correctness.

we believe that to make progress in this area, we should not constrain ourselves to teaching correct models and ideas about security; rather, we should focus on communicating models that are simple, coherent, easy to understand, and lead to desirable behaviors.


S ' 0 - S0 = y· H1(Y||A||0) + a mod p, S ' 1 - S1 = y· H1(Y||A||1) + a mod p.  4.2 DiscussionontheProposal Schemecan be considered as a variant of the Schnorr S signature.

(R ' ,S ' ,m) is a signature of the Schnorr signature on behalf of the signer, and (A,S b' -Sb,b), (b .


Now, the TPM and host together produce a signature of knowledge that T1 and T2 commit to a certi.cate and NV was computed using the secret key going with that certi.cate.

they compute the signature of knowledge SPK{(f0, f1, v, e, w, r, ew, ee, er) : f0 f1 -ew w "r Z = ±T1 eR0 R1 Svh(mod n) .


Before agreeing to compute a function f(s1,s2), P1 determines whether computing the residual function f(·,s2) would reveal too much information as determined according to a threshold 0 <t1 = 1set by P1.

p1 will not compute the function if P2 s belief about the likelihood of a possible secret value (including the actual secret s1) increases above t1.1 If P1 does reveal f(s1,s2)then it determines what P2 will learn from the output and revises its estimate d2 of P2 s knowledge accordingly.


The sharing policy language is designed for simplicity and intuitiveness similar to the IFS capability model.

there is no support for sharing between two IFS environments directly, which provides .ner-grained sharingbutwould complicate the language design and speci.cation.


For example, p(TaS)(x) and p(Tbs)(X) used during broadcast Bs will be dif-ferent (respectively) from p(7~9)(x) and p(r~)(x) used during broadcast B9 (except with negligible probability), hut the sum of any two corresponding shares of the same session key will be equal.

because the polynomials pt(x) and qt(x) are constant over all update messages, we must be careful that legit-imate knowledge of a point on one of these polynomials does not help a user learn anything to which he is not entitled, should he later be revoked.


Unpredictability can be de.ned as the amount of information an attacker has or can guess about the dynamic part of the attack surface in a given MT technique.

an MT technique is unpredictable if the space of possible movements is su.ciently large, where su.ciently depends upon the threat model.


This complexity can be greatly reduced by using a typical tree-like approach to determine if the maximum is on the left or on the right of a given interval.

one can run this aggregation scheme with only two possible values for the maximum, implementing it so that the participant caregivers return either one or the other as being closer to the maximum.


First, given the original sFSA representing the IDS, adjust the probabilities of the transitions in sFSA for the attack vector, the decryptor, the key table, and the encrypted attack code.

similar to the step of determining the encryption key discussed above, the sFSA is adjusted according to what have already been matched by these existing attack packet sections.


However, we stress that a more careful implementation of bit operations as well as pre-computing required inputs would further decrease the runtime of GSHADE.

all the values fi(0, Y j ) and fi(1, Y j ) can be computed once, when a data Y j is added to the database, and stored with the database, instead of computing them online.


As it turns out, the redirection chain length is not among the most important features.

having a short redirection chain is the 8th most important characterizing feature for a malicious web page, while having a long redirection chain is the 9th most characterizing feature for a benign chain.


The design goal of such an extensible representation is to make it easier to integrate other worm pro.ling dimensions.

the content-based signature of a worm can be added, indicating the occurrence of a speci.c content signature during that corresponding infection step.


Standard classi.cation algorithms, like decision trees or naive Bayes, can only assign one label (role) to one instance (entitlement) at the time.

even if we may have multiple labels (roles), each instance (entitlement) can only have exactly one label (role).


Note that the only kind of cheating which is possible is that cheaters may choose their own input.

cheaters cannot force the protocol to abort.


First, we provide the .rst detailed study of environmental sensor-based covert channels in mobile malware.

we present different .avors of out-of-band command and control channels based on acoustic, light, magnetic and vibrational signaling.


The main benefit of the propagation option is that it reduces the number of policies that need to be specified.

three different propagation options are supported: no propagation (NP), that is, the policy only applies to the protection objects which appear in the specification; first level (F), according to which the policy propagates to all the direct subelements of the elements in the specification, and cascade (C), according to which the policy propagates to all the direct and indirect subelements of the ones specified in the policy.


If any of the speci.ed predicates does not hold during the usage process, the ongoing access is revoked by the system.

an access control in UCONKI is not a one-time check and enforcement, but a continuous process.


The ideal strength and the design objective for a one-way function whose output length is equal to t-bits is to not to have a shortcut attack easier than brute-force and have a strength of 2t against pre-image attacks.

considering an ideal one-way function f(x) = y, for a given y having t bits, the number of computations required to find x is 2t .


In this paper we present a logic-based model for networks and attacks, which is suitable for carrying out automatic formal analysis of networks.

thanks to our model it is possible to, among other things, 1. given some (possibly partial) information about an attack (e.g.


5.1 A Levelwise Algorithm It is easy to see that a set of terms is K-safe only if all its subsets are K-safe.

the K-safe subsets of a document D satisfy the apriori criterion [2, 3].


The command ke,kd := Ge(); xLH := E(yHH,ke); xLH ' := E(0,ke) is computationally non-interferent (CNI).

we have xLH = xLH ' with negligible probability, even if yHH =0, so any IND-CCA2 encryption function must be probabilistic.


Once the signer issues a DCS, the veri.er can interactively validate it with the help from either the signer or the con.rmer.

for any alleged DCS, the con.rmer will .rst check its validity, and execute the corresponding protocol, i.e., using con.rm protocol (for a valid signature) or disavow protocol (for an invalid signature).


Note that the relational query processing back end does not require any change to the DBMS.

any commodity DBMS can be used directly with the logical trust management front end to form a trust policy evaluation engine.


For this purpose, we utilize the properties of a collision resistant hash function.

we map a number of incoming attestation requests to a single request whose nonce is computed as a hash of all nonces of the arriving attestation requests.


5.5 Keyboard Reconstruction In this section, we speci.cally discuss the stage of keyboard reconstruction, which is an essential part of keystroke recovery.

if the position of the keyboard is incorrectly estimated, all the inferred text is totally meaningless.


In our experiments, we found that using fewer than 37 gates yielded less consistency in the PUF behavior.

smaller PUFs increase the number of bit errors that must be corrected.


Within agivenHMM output sequence, weidentify all subsequences of S and M labels of length at least a, for parameter a.

(we disregard short subsequences, which tend to be spurious and erroneously skew S-to-M ratios.)


We restrict our discussion to work providing computational proofs for cryptosystems.

this excludes symbolic veri.cation (including ours).


Preventing malicious users from writing such a policy could be accomplished by only allowing the policy to be executed under their privileges, so that the e.ects of a policy are limited to anything that user is already allowed to do manually.

they should only be allowed to access view predicates under their own privileges, or built-in predicates which require no special privileges.


We note that functionally, bridge clients, clients, bridges, and relays all run the same Tor software, and con.guration options are used to determine which role a given Tor instance will take.

this means that whenever a bridge operator starts the Tor software so that she can surf anony  Figure 2: Circuit clogging.


This accurate birthmark should be able to re.ect the primary semantics of Android apps and tell independently-developed apps apart.

the designed birthmark should cause very few false positives.


As noted in [20], mimicry attacks against stack-inspecting gray-box IDS must not leave any trace of attacks on the call stack.

the attack code needs to use a jump rather than a call so that its address won t be saved on the stack.


Authorization are defined by another ternary relation, ....R, where ....R. .. × .. × R. In this case, (..,..,..).

....R iff a principal .. ... can perform the action ..... on the resource ...R. the triple (..,..,..) means that principal .. has the permission (..,..).


A fundamental assumption in content traitor tracing context is watermarking robustness.

given any set of watermarked variations t = {v1,v2, ....vk } for a segment, it is impossible to delete the watermark or generate another pirate variant vj ,and vj .


Flexible and Secure Enterprise Rights Management based on Trusted Virtual Domains Yacine Gasmi, Ahmad-Reza Sadeghi, Patrick Stewin, Martin Unger, Marcel Winandy Chair for System Security Ruhr-University Bochum, Germany {yacine.gasmi, ahmad.sadeghi, patrick.stewin, martin.unger, marcel.winandy}@trust.rub.de Rani Husseiki, Christian Stüble Sirrix AG security technologies, Germany {r.husseiki, c.stueble}@sirrix.com  ABSTRACT The requirements for secure document work.ows in enterprises become increasingly sophisticated, with employees performing di.erent tasks under di.erent roles using the same proprietary platform.

.ne-grained access control to document information is necessary in certain scenarios where the integrity and con.dentiality of parts of documents is of high priority.


The type for formulas used here is the type form declared in the shared interface.

aCM s logic provides local instantiations of the abstract concept formulas.


The fixed policy approach assumes that the security decisions embedded in the design are a fit for the widest range of users; in contrast, the dynamic policy approach assumes a fit for individual users.

the extent to which a security policy is predefined depends on where it lies on the spectrum of policy rigidity.


As showninFigure1,theNIDS applicationis mapped tothedifferentprocessing unitsusingboth task and data parallelism across the incoming network .ows.

the network interface distributes the captured packets to the CPU-cores, ensuring .owpinning and equal workload across the cores.


This theorem indicates that to ensure unp-privacy, the computational power of tags cannot be weaker than that of computing a PRF.

the minimal requirement on tags to achieve unp-privacy for RFID systems is the ability to compute a PRF or its equivalents such as one way function and cryptographically strong pseudorandom generator [11].


Conversely, the work in [29] modi.es the PHP virtual machine in order to propagate taint information.

the modi.ed virtual machine includes the .eld labels to store taint meta-information.


of reduced computational e.ort for bundle sources versus increased bandwidth overhead and processing requirements at receivers seems questionable.

if bundle sources can also take the role of intermediate forwarding nodes any bene.t of the solution becomes void.


4.1 Grouping scheme There is an observation: anchored signatures must appear only at the beginning position of the input payload.

if the first character within a flow is not accepted by the finite state automata constructed from an anchored signature, there is no need to compare the rest of payload against this signature.


We explore China, Syria, Iran, and Egypt as routing capable adversaries, and evaluate several attacks that defeat the security goals of existing decoy routing proposals.

we show that a routing capable adversary can enumerate the participating routers implementing these protocols; can successfully avoid sending traf.c along routes containing these routers with little or no adverse effects; can identify users of these schemes through active and passive attacks; and in some cases can probabilistically identify connections to targeted destinations.


In Shamir s scheme, the higher the degree of the polynomial, the higher the number of shares required to recover the original secret value.

if the degree of the polynomial is k-1, at least k shares are needed to reconstruct the original value where k <= n. The higher the value of k, intuitively it is more difficult to break the security but then one must pay for more computation overheads due to a higher k. There are four types of computation overheads in Shamir s scheme.


Therefore, the runtime allocation of ordinary tasks on the one hand and tasks that are allocated via a break-glass override on the other hand must be clearly separated.

this means that a subject cannot accidentally perform a break-glass task.


The basic obfuscation LPPM, with an obfuscation level k =1, 2, 3,..., is constructed in the following way: For each location r, we .nd its k -1 closest locations (using the Euclidean distance between the centers of the regions).

the 1The tracesareobtainedfromtheLausanneDataCollection Campaign dataset, http://research.nokia.com/page/11367  probability distribution function f(.|r) will be the uniform probability distribution on the set of the k -1 selected locations together with the location r. location r is replaced by each of the k locations, as a pseudolocation, with the same probability k1 , and all the rest of locations have probability 0.


The regular expression functions are data stream-based rather than string bu.er-based.

they must be able to cope with scattered message arrivals.


When there are multiple adjacent malicious routers on the intended path (Rj1 to Rjn), a wormhole is present: an honest router down the path can only conclude that the packet has entered into the hole via Rj1 and exited the hole from Rjn, but has no knowledge as to where the packet has been to in between these two points.

when the source colludes with Ri, Ri+1 can be tricked into accepting and forwarding any packet.


EHR SHARING SYSTEM As part of our ongoing research e.orts, we have designed and implemented a proof-of-concept system, called InfoShare, which is a simpli.ed clinical information sharing systemthat utilizesourproposed modelforapatienttocontrol access of his medical information.

infoShare collects apatient s access controlpolicies aspatient consents, and uses these consents to selectively share the patient s medical information as contained in the virtual composite EHR with di.erent requesting parties through a point of service(POS) web application.


The SPIR protocol we use has the additional property that it is secure in the real/ideal model.

to guarantee the user does not learn more than a single index i of the database x, there is an e.cient simulator which can extract the index i learned by any (possibly malicious) user U * interacting with the honest server.


For instance, it would be interesting to .nd out whether users actually would change their input strategy in di.erent contexts as proposed in this paper.

if they would use the faster one-stroke approach in crowded situations and the more secure accumulative method if there is no time pressure.


MemSherlock requires a pre-debugging phase to collect the information needed for security debugging.

it needs to collect the write set of each critical memory region.


nShield learns if a polling round is successfully complete, by examining the logic of the polling messages of consecutive polling rounds.

some polling messages, such as the Single Device Detection Request and the Select Request de.ned in the NFC-A standard, can only be transmitted if the previous polling round succeeds.


Each vertices in the cycle is passed only once.


Since now there is not a runtime and debug environment for the smali code, we can only implement a data.ow analysis technology on the smali code.

our target is to know the two Activities linked by an Intent.


FORMAL RESULTS In this section, we state the correctness of the proposed solution, proofs can be found in [3].

we show how the proposed framework is able to enforce the considered security properties.


For example, any checksum, including the one used in TCP or UDP, is only computationally sound rather than perfect.

there is negligible but greater than zero probability that a checksum-protected packet is indeed corrupted but undetectable.


Thus, the .gure demonstrates that the rate at which new victims are observed .uctuates over time, and because of this .uctuation, the detector will observe a distribution of new victim arrival rates.

the rate at which new victims are observed is governed by some random variable N with some distribution.


1.1 Our Results MPC for the Masses Our main goal in this project was to implement a system that enables casual non-interactive multi-party computation (Canon-MPC, for CAsual NON-interactive MPC).

the system should enable its users to run secure computation without complicated setup phases, and without downloading, compiling and setting-up any software.


Once a patient understands the default policy and agree that it meetshisneeds,thepatient may notneed tofurtherspecify any speci.c access control policies to control the sharing of his medical information.

hIPAA regulations are widely adoptedbyhealthcarepractitionersin theUnited States.


What we are most interested in is evaluating the impact on running time of the new elements introduced in this paper.

whenever more than one rule applies to the received access request, the PDP should compute the most speci.c context and apply the corresponding rule.


That said, we realize that in a proposition like ours, the security of the system depends on the space of possible blends; thus one must fully explore the security implications of that restriction.

past research on analyzing the security of passwords has followed one of two approaches.


{(s, o)}) T.((reg, cf,m), (s, o), deny)=(reg, cf,m)  2.3 Utility and Reward Function An important aspect of a decision process is the ability to give a utility value to a decision or a state.

it is possible to express the interest for the system of making a given decision in a given state, and we introduce an utility domain U.


3.2.2.3 Thrashing Detection and Workarounds During the testing process of the VMX handler, it was discovered that the S-TLB would not permit two entries for the same address loaded for the same instruction.

when instructions were within the same (4KB) page as the data being accessed, the VM EXIT handler would replace the TLB entry for data with the instruction address and vice versa, causing an infinite loop (thrashing back and forth).


For example, two MITRE technical reports [13, 26] highlight the fact that the lattice-based access control scheme relied upon by the U.S. Armed Forces is beginning to show signs of age.

[13] cites several examples of improper and unauthorized outof-band data sharing that have occurred because it is easier to ask for forgiveness than for permission, given the high delays and human costs associated with utilizing the proper channels.


[14, 3]) to be of signi.cant help towards a solution for this problem that may be provably-secure under standard cryptographic assumptions; the main idea being that previously stored data in encrypted form can appear as logically deleted data to whoever does not have any information about the decryption key.

encryption reduces the problem of securely deleting large amounts of data to the problem of securely deleting a single encryption key.


Consider a case where this user requests resources from the network, breaching the security policy of the system.

the user tries to get from the system resources but he has no right to do so.


In order to avoid the signi.cant runtime overhead introduced by the large amount of the device output logging, Aftersight adopts the approach of replay based replay .

aftersight records external inputs to the device during normal execution, logs the device outputs to CPU during the .rst replay, and .nally replays the second recording for analysis.


According to the last part of Proposition 4.2, there is a homomorphism hfrom Jto core(Jn)such that hWv, for every vin core(n).


Rm and |Rm|= t, we can use a one-dimensional array with j elements to indicate the number of revoked members in each session.

we can represent all {Ri}i=1,...,j by Rj and this array.


In our design, we further enforce W.X [2] in the KVM address space.

there is no memory page in the isolated KVM address space that is simultaneously executable and writable.


While faithfully following all SPH-PSM protocol steps, Bob inputs a concocted genome t ' where ' ''' '' t [s : m ] = p and m = |p |.

the sub ' '' string in t starting at position p is set to s .


For a motion-MIX, this requires the inside nodes process each type of packets independently.

if there are m types of packet in the network, every node must run Algorithm D for each packet type independently.


Intuitively, the ideal interface is too good to be true: a simple information-theoretic argument shows that any implementation such that (1) MACs are shorter than texts and (2) MAC and VERIFY communicate only through MACs must be unsafe.


In a final set of tests, we explore the effect of the parameters m, k and c on the construction.

we are interested in measuring the difficulty of construction, and hence the feasibility of the hash-table, when parameters change.


The idea was to intercept all keyboard events before they reach the JavaScript engine.

we aimed to disable the delivery of events to the JavaScript engine while the input focus was on a form element.


Thirdly, according to the legislation of some countries, such astheDigitalMillenniumCopyrightAct[1], Germany s penal code (§202a), and the United Kingdom s Computer Misuse Act, automatically recovering the text from FHEOgenerated imagesthat arefoundinthewild,potentiallycarriesacertainlegal risk.Inlight ofthis,the exact levelofprotection that FHEO o.ers against recovery attacks may be, to some extent, irrelevant in the a.ected territories.

even the easy distortion pro.le may su.ce to prevent some of the automatic processing of messages protected by FHEO that would otherwise be automatically processed in these territories.


This paper describes the design, implementation and evaluation of the RTKDSM system, whose goal is to facilitate the development of VMI applications by alleviating them of the task of closing the semantic gap.

a VMI application just needs to specify kernel data structures of interest, and the RTKDSM system is responsible for tracking down the memory locations of these data structures in the monitored guest OS, and notifying the application immediately when these data structures change at run time.


But even with the present simplistic approach, both the code for the lattice operations and their proofs of correctness are signi.cantly more elaborate than for the trivial two-point lattice.

we need an additional code generator to build counted loops, e.g., for computing the join of two tags.


Each disease under the Conditions section is also associated with a distinctive payload sequence.

every time a user clicks on a condition she is interested in, the app produces 4 GET requests (with 3 GETs for ads); and then 3 POST requests to acquire the content for that condition.


In practice, f'  = f, because it is nearly impossible to correctly emulate some aspects of hardware.

for some i, Si'= f'(Si-1,Ii-1) and Si' = Si.


On the other hand, naturally, the anonymity of the receiver of an original message is only protected so long as the message was sent by a honest sender.

the privacy of a receiver is conditional on the sender not being controlled by the adversary.


In the current paper, we consider key management schemes for geo-spatial access control.

the access control policy assigns to a user a speci.c geographic area, and the user consequently obtains access to her area or information about it.


Another related proposal called SOMA [24] implements a mutual consent policy on cross-origin links.

both the embedding and the embedded content must agree to the action being initiated.


The user should also be able to define the string being encrypted.

the user should be given the option to use an ASCII string, a hex string, or a binary string.


We refer to these interfaces as .ltering interfaces.In CW-Lite, low integrity permissions are only accessible through .ltering interfaces via .ltering subjects.

the permissions of .ltering subjects are only available when the code of a .ltering interface is run.


A Example of a Program with a Call to a Function with no System Calls 3.3 Invariant Generation and Assertion Checking Figure 6 describes the result of running Daikon on the program with respect to the function main.

all of the likely invariants that Daikon discovers about the function main and all functions and system calls within the body of the function main, and by running the program and providing respectively the inputs /csl/bin/library , 3, and 3, as the respective values for the variables input, i,and j. Daikon captures the fact that arguments of functions and system calls are constants.


To match two unequal-size graphs g and h, we extend the vertex SS set of each graph as: Vg * = Vg Eg and Vh * = Vh Eh,where Eg and Eh are sets of dummy nodes created to account for insertions and deletions.


In general, AL I B I limits the options of in-.ight modi.cations of guest state available to the platform.

it only allows changes to RSP and RIP that are consistent with handling of guest-mode exceptions (e.g., emulated I/O requests) that, typically, amount to advancing the RIP register to the next instruction following the one that caused an exception.


Current integrity measurement protocols can only measure the integrity of the code and static data(e.g., con.guration .les) [23].

these protocols cannot attest the integrity of dynamic data structures in kernel memory.


Action of owners: Although an owner id is unlikely to counterfeit the tokens she proposes, she may ask an authority to generate a token with OWNER attributed in other people s name to access .les not belonging to him/her.


we allow for the adversary to query reencryption of any ciphertext apart from the challenge ciphertext to any delegatee, even a corrupted one for which the adversary knows the secret key.


A closer look at these malware samples reveals that they frequently connect to the Internet, suggesting that they might act as valuable tool for Pay Per Install (PPI) providers.

the samples might download additional malware from remote locations or function as remote controlled bots by connecting to command and control (C&C) servers (i.e.


However, both systems use contextual information to make their detection accurate.

sURF looks at the search engine results that attackers poison, while WarningBird looks at the characteristics of the social network account that posted the link.


As we outlined in the previous paragraph, models and policies play a central role for the feasibility of model checkingbased validation.

the security state of each mobile device is evaluated against the models of the installed applications.


Since modi.cations to attributes of one user have no impact on potential changes to the attributes of other users, we only consider the attribute assignment of a single user of interest in a state.

we assume U = {u} in all of our analysis.


The string representation of a class is a concatenation of its name, super class name, implemented interfaces, class and member .elds, and methods.

a method consists of its signature (i.e., parameters, return value, and exceptions it may throw), name, and disassembled instructions.


Therefore a large part of the attack space has not been addressed.

the class of detectable attacks that do not trigger conventional alarms has yet to be covered in depth.


Vc ) and writes only tainted variables (wv(A) n VI= Ø).

a can al ways read variables with con.dentiality label .c and always write variables with integrity label .I .


If anyone gets physical control/access of/to the drives withouth the mounting passwords and keyfiles, the drives cannot be decrypted.

the data cannot be accessed without both the information in (5) and the password.


The performance was also affected by the type of a benchmark used in the experiments.

the Apache benchmark had a significant impact on the performance due to spurious page faults resulting from running this benchmark.


If this may happen, such a state is not considered safe with respect to that right.

a model state q is called HRU-safe with respect to a right r if there is no sequence of inputs that writes r into an ACM cell that in q did not contain r. A general answer to this family of questions provides fundamental insights on right proliferation in access control systems.


A typical implementation of such a GSCS stores the entire spatial network.

on top of the declared location claims of the users, the graph-like spatial knowledge base is actually tracked by the GSCS in order to support the evaluation of policies.


Authentication The user enters four passwords of each category.

a total of 12 passwords are entered in randomized order.


Experience with this policy guided our choice of complexity parameters and restrictions for the analysis algorithms in Sections 3 4 and suggested realistic values for some of the parameters used in random policy generation in Section 8.

we note the following characteristics of the policy: Every can_assign rule has at most one positive precondition, so the analysis algorithm in Section 3 applies.


TMI o.ers improved protection against violation of complete mediation by ensuring that the reference monitor is implicitly invoked whenever shared, security-relevant resources are accessed within a transaction{...} code section.

with TMI, a developer need no longer identify and guard individual resource accessesasin Figure1(a).


Based on the security policies of the Jif code, the compiler chooses annotations that ensure code and data are placed on the client only if the security of the program will not be violated by a malicious client.

thetranslation ensuresthatdatamaybeplacedona client only if the security policies indicate that the data may be read by the principal client;data may originate from the client only if the security policies indicate that the data is permitted to be written by the principal client.


Our goal is to avoid too restrictive and too general use of parallelism found in prior work and instead incorporate enough .exibility that will provide fast runtime of compiled programs.

in frameworks similar to ours, Sharemind [10] provides parallelism only at the level of arrays, where multiple instances of an operation applied to each cell of the array are performed in a batch.


And the SP can choose to block a misbehaving user for the rest of the month, or until the end of the week, or for the day, according to the severity of the damage the user caused.

with the extension of multi-blacklists, SPs have freedom to block a die-hard vandal for as long as they want, and to cool down an edit war by temporarily blocking the editors involved for a short time period.


To cope with all threats, we propose to use symmetric cryptographic algorithms.


An evaluation involving all signi.cant x86-32 Linux security patches from May 2005 to May 2008 .nds that most security patches 56 of 64 require no new code to be performed as a Ksplice update.

ksplice can correct 88% of the Linux kernel vulnerabilities from this interval without the need for rebooting and without writing any new code.


For convenience, we denote the complete version of our solution as P.Complete.

we disable both the interactive recommendation and the abnormality examination functionalities to create a plain pro.le-based recommender called Profile.Profile recommends recipients only once per .le sharing instance and does not examine user input for abnormality.


This de.nition is actually more general than Kobayashi s, who limited a loop body to contain the same machine instruction only once.

there is no instruction f .X 86 such that a = ufu ' fu '' in Kobayashi s work.


We speci.cally aim to provide a safety net for users, so that a moment of inattention will not immediately result in identity theft.

we are attempting to make phishing signi.cantly more di.cult for the attacker.


We say that the adversary Awins the game if the following two conditions hold: The decoder PD is perfect.

for a randomly chosen m in the .nite message space, we have that Pr[PD(Encrypt(bk,m)) = m] = 1 (13) The set S is either empty, or is not a subset of T. We denote by TR Adv[A,TT (n,t)](.)


4.4.3 Latency hiding BottleCap, like any Flicker application, su.ers from problems of latency.

the combination of DRTM invocation, TPM unseal operations, and the inability to overlap either of these with multiprocessing techniques results in a high performance penalty for the use of BottleCap.


In mostcases,theintentissimply tore-establish User s location, the role and User s credentials are not needed.


W is the set of weights w of different opinions, such that wi is the importance rate of .i on the evidence evi , or wi is the weight of opinion .i on an entity, where .i .. the set of opinions on an entity.

[]and .=1;  wi .0,1wi 4. x.y.z is the value of parameter z of y in x; e.g.


However, for the attacker, the size of potential pro.le set (that may contain the target) under this de.nition is successfully decreased from n to k. To assess the identi.ability of D, we further count nk-, which is the number of pro.les that cannot be identi.ed from at most k other pro.les given seed information {attr1, ..., attrr}.

for every possible value set {v1, ..., vr} in the seed attribute tuple space Rr , {v1,...,vr}{v1,...,vr} nk- = sum(IT ), for IT <k.


We show that these simple and familiar metaphors enable a rich space of policies that will be systematically investigated.

we show that the temporal interactions of users joining and leaving the group and information being added and removed is critical to determination of who can see what in the group.


We have explored a wide range of API calls in order to demonstrate the feasibility of our approach.

we provide support to mock the following: Coarse-and .ne-grained location if read requests are mocked, then the application never receives a callback with a location .x, simulating lack of available location information.


For performance reasons, Ext3 s journal merges write requests to the same block if these requests are within the same transaction.

under a single transaction, if one changes some buffer-heads multiple times, only the last change will be committed to disk.


Security analysis provides a means to ensure that security requirements (such as safety and availability) are always met, as long as users identi.ed as trusted behave according to the usage patterns discussed in this section.

security analysis helps ensure that the security of the system does not depend on users other than those that are trusted.


6.3 RelationbetweenU-ProveandIdemix The signature schemes that underlie U-Prove and idemix are similar.

they are both schemes that allow an issuer to (blindly)sign messages where the messages are algebraically encoded as exponents of a representation of an element of an algebraic group.


As stated in [5], the proposed scheme cannot achieve the anonymity de.nition if someone could obtain multiple re-encryption keys per pair of users.

if the cloud possesses multiple re-encryption keys for the same pair of users, then it can derive the identities involved in these re-encryption keys.


To achieve differential privacy for this query, we add a bit of noise to the output of the deterministic query.

when thedeterministicquery returns a vector of real numbers, we can apply the well-known Laplace mechanism [12]to analyze the underlying function and apply the appropriate amount of random noise to achieve o-differentialprivacy.


In section 4 we define the concept of Accessibility Space, which is a collection of permissions related to a subject.

we identify seven important accessibility spaces, essential for the analysis of an arbitrary system configuration.


We assume a unit-disc model for Wi-Fi communications, in which a user and an AP can communicate only if the distance between them is lower than a given radius R, which is constant across all users and all APs.

we assume that users cannot violate this model by, for example, increasing the transmission power of their devices.


Since both sender and receive follow the same protocol, our second set of experiment simply measures the performance overhead of remote attestation for the sender.

for the CoCA, we measure 1) the latency it generates a random nonce n, encrypts n with its AIK key and the sender s public key as a challenge c, and sends out c; 2)the latency it veri.es n, which returns from sender.


However, we are now looking for a normalized value.

we want to make the obtained value normalized to a reference interval.We consider as reference interval the one from0 to maxDist +ßD, that is the interval of all possible accepted values.


Our work closely follows the secure-by-construction philosophyofbuilding application software.

we envision RIPLEY becoming an integral part of the next generation of application servers.


The version P left Q discards the response from Q and returns the value from P.A typical use of this combinator in our algebra is to use Qas a continuation for the future with responses to policy queries, if any, coming from P. We have binary operators on policies corresponding to the boolean operations e.g., a binary combinator P or Q imposes the constraints of both P and Q but also yields a response to an access query that is the disjunction of the responses of the individual policies P and Q.

an interesting combinator in this .avor is an overriding combinator P def Q that overrides the results given by Q by those provided by P. the results of Q are used if P does not provide a response to the access request.


The multiple graph approach provides a signi.cant advantage about 35 times faster for the peak in the .gure for some parameter values.

it does best with a large number of rows and a small number of columns.


Propagation of tick ets is still a problem, but their timed validity limits its extent.

tickets must be reissued by the holder of the capability, on his/her machine, meaning any long-term capability-sharing must involve his/her active participation (similar to the Non-Delegable Authority concept in [27]).


The history of the nuclear power activism suggests that now might be the time to broaden the scope of privacy issues, to use increased media coverage to link privacy issues to a variety of global concerns, to find common ground with existing activist organizations, and to take advantage of the modest, though significant, successes of welling popular social movements, such as resistance to the World Trade Organization and the biotech industry.

we will attempt to answer the following questions: How philosophically and politically expansive can privacy issues be?


We may also refer to a process that is happening internally or externally.

these terms re.ect the viewpoint of the monitored VM.internal refers to a function or process that occurs within the monitored VM, while external refers to a function or process that occurs within the VMM or a privileged VM.


However, they do not allow partial delegation.

our objective is to develop a more .exible sort of delegation scheme.


next let C be an unauthorized set of the participant set P. C is a subset of P which is not equal(or does not contain) B1 or B2.


Unfortunately, none of the available deniable .le systems provide a solution for the scenario proposed earlier in this section, where an adversary obtains access to a laptop and also records communication.

none of the existing schemes can be applied to the cloud environment.


Finally, in addition to considering the role of human-computer interaction (HCI) for evaluating systems, we also propose considering methods for design.

fieldwork tech- niques could also be used to observe candidate settings for secure applications.


[1] introduced the model of leakage-resilient chosen-plaintext (lr-CPA) security and showed that the lattice-based public-key encryption scheme of Regev [29] and the identity-based encryption of Gentry, Peikert, and Vaikuntanathan [13] were lrCPA secure.

regev s encryption scheme is resilient to any weak key-leakage of L(1-o(1)), where L is the length of the secret key.


To help ensure participants take the task seriously they were asked to imagine that this opportunity was their one chance to get their advisor to pay for all of the equipment and travel, the everyday financial realities of their research.

each participant was asked to compile first an individual budget, and then create a justification for each expense.


STRENGTH EVALUATION In the following, we give a framework to analyze the collected data about Android Unlock patterns regarding their strength.

we need to establish a formal notion of password strength .


and this bit-string is appended to the list, unless it was already present.

a cannot access an element of G directly but only through its name s(x)and theoracle provides names for the sum or di.erence of two elements addressed by their respective names.


In particular, since the two considered algorithm DTW-D and DTW-S work in different ways, we also considered for the two of them different set of threshold values.


However, we argue that an adversary might not have any control to the set of known queries.

it is most likely that an adversary does not get to choose the set of known queries himself.


4.2 Security requirements The objective of our protocol is to securely evaluate T on V.The protocol should reveal nothing to the Server.

the User should learn T(V), which is a classi.cation label contained in one of the leaves of the branching program T. The User is also permitted to learn the total number of nodes of T (see the discussion in Section 4.6) and the length of the path from the root node of T to the leaf containing the result of evaluation, i.e., the label assigned by T to V. The User should not learn anything else about T. the User should not learn which attributes from V have been considered by T, with what threshold values they have been compared, the outcome of any comparison, and so on.


Among these writes, there is no single write to the set of 5, 881 kernel hooks for protection, while the number of writes to the 41 memory pages that contain protected hooks is 6,479,417.

about 1% of kernel memory writes would cause unnecessary page faults and thus introduce expensive switches between a VM and a hypervisor.


It is important to note that false positives that occur after deployment would be due to the use of external data sources that have never been used during in-house testing.

false positives are likely to occur only for totally untested parts of the application.


Second, we do post-processing using MLE.

we take k di.erent subsets of measurements and obtain k di.erent sets of characterization results.


Security analyses of Web Services protocols resemble analyses of traditional security protocols in many respects.

owing to the distributed-system aspects of multiple interleaved protocol runs, both Web Services and traditional security protocols analyses are known to be error-prone and awkward to make for humans.


In fact, as we prove in Lemma 19 (in Section 5.5 after results needed for the proof have been developed), for every k and n such that 2 < k < n, there exists no set of SMER constraints that precisely enforces a k-n RSSoD requirement.

the two special cases in Lemmas 10 and 11 are the only cases where precise enforcement can be achieved.


CONCLUSION We have developed three one-gate hardware Trojan attack models that can bypass the widely used side channel-based HT detection schemes and pose threats on the security of wireless systems.

the HT models leverage a single HT trigger that exhibits rare switching activities, consumes ultra-low leakage power, and hides from delay characterizations due to reconvergent paths.


If the mode is READ, then a host holding a clob can use it an unlimited number of times, as long as it has not been migrated from that host more than its count limit.

(if the host migrates the clob more than n times where n is the count limit in the host s copy of the clob, then the counter exceeds the count limit and the host s TPM starts disallowing use of that clob.)


In this paper, we present a way to probabilistically detect malicious cars that generate false aggregated information.

we focus on validating speed and location information, which is common to most vehicular applications.


The expected time to defeat integrity by a parallel attack is simply m. 3.9.3 Availability The time to compromise all n components by multiple attackers is the largest of n samples of the independent random variables distributed according to f(t).

this is the nth order statistic, t(n), and, as is shown in the technical section of this paper, E(T(n)) .ß as n .8 where ß is the rightmost value in the support of f.ß is the smallest value (in.mum) for which f(t) = 0 for all t>ß.


We have used our JavaScript information .ow framework to detect and study the prevalence of such attacks on a large set of websites, and show that history hijacking is used, even by quite popular websites.

policies We formalize history hijacking in our framework using the following information .ow policies: at $1.getCompStyle($2,...) if $2.isLink() inject secret at document.send($1, $2) block secret on $2 whenever the computed style of a link is read using getCompStyle, the return value is marked as secret.


(Ei,Fi) () Return (pkDB, ER1,..., ERN ), skDB Figure 3: Database Setup algorithm To set up the database, the database provider runs the algorithm shown in Figure 3.

it uses the issuer s public key and a pairing group generator to create goups of thesameorder p and generate keys for encrypting records.


Unfortunately, the same concept does not apply to mobile applications.

for both iOS and Android, installed applications do not have an origin associated with them.


Such rewriting is enabled by relaxing the requirement of exhaustive matching to that of nonoverlapping matching.

we propose two rewrite rules, one for rewriting specific patterns belonging to the case of quadratic-sized DFAs (Case 4 in Section 3.2), and the other for rewriting specific patterns that generate exponential-sized DFAs (Case 5 of Section 3.2).


For demonstration purposes, Figure 8 highlights three areas of the BPMN model and the corresponding XMI representation.

thehighlighted areasinclude thefollowing elements: Lanes partitioning the process are de.ned via lanes elements with the xmi:type attribute set to bpmnxmi:Lane.


OUR APPROACH In this work, we explore a novel 3D object based CAPTCHA system, which essentially combines the benefits of 3D text CAPTCHA and Sketcha to make the CAPTCHA system more secure, robust, and less vulnerable.

our approach first asks a user to solve the 3D object rotation problem, similar to Sketcha.


> > > > current time(T ), > > > > month(T, M )  > > > sales(V, M, widgets) < ., : V = 5000.

a0 speci.es that users with a status level between 1and5can access anyobject in r2 if the user has this permission assignment speci.ed via the IBLP p.1 and the system load factor is less than or equal to 2, as recorded in the IBLP ..


In [23], uncoded  OFDM is simpli.ed by setting ui = ai, wi =1, .wi =0, and NF -1 .oi =0 .i.

all assigned frequency components are assumed to be used and there is no windowing or built-in .


Finally, one issue that complicates security practitioners work is related to the inherent uncertainty of their tasks.

our participants mentioned that they are never certain as to the correctness of their activities (P3).


This includes new Objective-C classes the developer implemented himself and classes that have been already pre-de.ned by the Objective-C runtime.

we reuse the existing tools [14, 13] to record for each call to the objc_msgSend dispatcher function the referenced Objective-C class and selector.


The mapping from our structure to the original data set should not require that the data be re-sampled.

we want to retain the original volumetric data.


In smart grids, the real-time price signals are exposed to di.erent security threats at the source, during network transmissions, and at the consumer-level smart meters.

recent studies [22, 26] have shown that many smart meters lack basic security measures to ensure the integrity and authenticity of their input/output data.


The obstacle comes from the setting that in CP-ABE the decryption privilege of a user is determined by his attributes rather than by his index as in broadcast encryption.

in AugBE [6, 9], the indices of users are simultaneously used to determine users decryption privilege (for broadcast encryption part) and to identify users (for Tracing), and the construction and the proof of indexhiding of AugBE [6, 9] are based on this fact.


More precisely, for each access token that is related to a write operation, we check whether there exists a corresponding read token.

for all applications that have written to a folder, we check whether they have also performed read operations.


For signature schemes, we try to optimize further by reducing the public parameters used per algorithm.

we trace which variables in the public key are actually used during signing and veri.cation.


These coe.cients are uniformly random since B chose uniformly random A. B1 outputs 0 (ß = 0) if ./C0 = 1, 1 if ./C0 = 1.


To overcome security issues in WBSNs, we propose a digital watermarking scheme based on Wong s algorithm [1] which involves simple mathematical operations that make it suitable for implementation on low-powered sensors with limited computational resources.

we focus our studies on electrocardiogram (ECG) signals for this paper, but the proposed algorithm can be applied on any sampled streaming data.


algorithm and provides the adversary with all decryption keys corresponding to the set of attributes GR = G(ß1 n ß2 ...n ßn)with |GR| = R.the adversary is provided with the private key dku = r(ß+su) su su su su (g ,g ,...,g ,gn+2,...,g ,di1 ,di2 ,...,diR )where 11 n 2n dij .G(ß1 n ß2 ...n ßn)and su .R Z/pZ.


On the other hand, evil twin attacks are quite effective, yielding much higher fatal error rates.

l-VS-CS appears vulnerable to this attack, since at least one group member accepted the pairing in almost half of attack cases, irrespective of group size.


This choice is deliberate, as our protocol is intended as an overlay on top of an existing network infrastructure.

we assume thatsystemimplementers apply cryptographic techniques as necessary.


A mixed strategy for player A is a distribution .A on protocols.


Potential security holes arise from the fact that the resources are shared between multiple tenants and the location of the resources are potentially unknown.

sensitive data or protected applications are critical for outsourcing issues.


Partition S into a m × n array of tiles Si,j , 1 = v v i = m and 1 = j = n, where each tile is itself a v v m × n grid.

si,j consists of the cells of v S whose row number is in the interval [(i - 1) m + v 1, i m] and whose column number is in the interval v v [(j-1) n + 1, j n].


However, most of the research focus on modeling, veri.cation, analysis, and testing of XACML policies (e.g.,[4,6 8,11]).

the focus ofprior work onXACMLis the correctness ofXACML policies while the focus of this paper is on the performance of XACML policies.


Our technique protects software without human intervention using either compile-time or loadtime rewriting to add active, diversity-based defenses with no run-time overhead.

we focus on extending the compiler or loader to weave dormant, active defenses into generated binaries.


We also aim to maintain usability (QoS) and economical e.ciency.

we study two channels that may take suspicious inputs: user control commands (UCC) and realtime pricing (RTP).


It is easy to check that the number of keys assigned to u is cd.

the size of the user-key set K(u) or the storage size is cd.


Fourth, while the system is OS-and application-neutral, when an attack is detected, we inject OS-speci.c forensics shellcode.

we exploit the code under attack as the attack is happening to extract additional information about the attack which is subsequently used in signature generation.


However, we believe a more ef.cient approach is to create a list of prohibited permissions associated with the user u.

we maintain a blacklist for each user consisting of a set of permissions.


4.4.1 Push and pop instructions push and pop instructions are used very often in ROP.

they are used together to transfer the value of one register to another, the latter typically being esp.


In the CHS scheme, the answer to a given POSH must not be known at login-time, because if it is, it can be accessed by the attacker.

the POSH generator cannot simply take pi and display a CAPTCHA of pi, because the attacker also knows pi given a password guess (and thus knows the CAPTCHA s solution).


_: RT x T4[L] --+ Ti[RT x n] ]s<tA (s, ~) ~ (t, y) } It follows from this definition that if my confidence is r that P is upheld then the same policy can be upheld if I decrease my confidence level to s < r. EXAMPLE 6 Figure 3 gives the possible flows in the rated policies mls ~ PALM and palm o ~ PALM based on the rating ordering R1 fl'om Figure 2.

a Note that a policy rated at '0' (from Figure 2) does not represent complete uncertainty, rather it repre- sents uncertainty at all levels except the lowest level LEMMA I Given ratings r,s, and policies P, Q : T~[L] then it follows from the definitions of ~ and _ that r<sAPEQ~r]PEs$Q the rated policy r : P can be replaced (re- fined) by the higher rated policy s : Q without any loss of confidence.


However, the bene.ts provided by the TCP/IP protocol suite do not come without a cost.

now power grid devices must be concerned with traditional network threat vectors, including attacks against protocols in the TCP/IP protocol suite.


In situations where there are adversaries who may want to intercept and/or interrupt the communication, security becomes one of the top concerns.

it is critical to make sure that the adversaries cannot access or interrupt the wireless communication, and even if they do, it is possible to recover from such compromises quickly.


From our analysis of the existing location privacy metrics presented in Section 3 and the description of our distortionbased metric in Section 4.1, it is clear that the proposed formal framework, speci.cally the linkability graph model (Section 2.5), clearly captures the required criteria to measure location privacy.

the adversary model assumed in existing metrics and the proposed distortion-based metric can also be captured within the linkability graph-based model.


After describing each of the four domain models, we develop the access control models.

we introduce the concepts of authorization set and protection state, and identify necessary constraints.


In summary, the threat model in our studies is as follows: Adversaries have access to everything except passwords or the information accessible only with passwords.

adversaries have access to the discretization information, user IDs, and hash values of passwords stored in the system.


To further increase their revenue, retailers have been successful in personalizing purchases by focusing on individuals rather than crowds.

customer pro.les are created and shoppingpatterns of customers are collectedtobe used in smart algorithms that generate a set of products, which are likely to be purchased by a target customer.


The proposed biometric measure is not only effective, as proven by the results; it also enjoys a unique feature.

it can be transparently used to authenticate a user that is answering (or placing) a phone call, without this being affected by external factors (like light exposure or users wearing hats or veils).


In order that only the nonrevoked users can decrypt the encrypted contents ESK(M), the center attaches an additional data called header,which contains some information to be used for non-revoked users to compute SK.

the center broadcasts ( header ; ESK (M) ).


There are, however, certain drawbacks to using probabilistic methods such as dynamic analysis and fuzz testing.

both techniques may suffer from coverage problems.


As de.ned above, a router that announces its new best AS path for a given address block to all of its neighbors must send a slightly different attestation to each of its eBGP neighbors.

to announce the route r it must send r, RAT (r.a)to an eBGP peer in AS a,and r, RAT (r.a ' )to an eBGP peer in AS a ' etc.


STM systems provide many useful guarantees that make the implementation of multithreaded software easier and less error-prone.

sTM offers atomicity and isolation through optimistically executing concurrent code and monitoring for con.icting accesses to resources.


We propose to achieve such hiding by moving the control ancestors of selected statements that be- long to forward data slices of hidden variables.

control ancestors are hidden if doing so will simultaneously introduce a control flow construct in the Hf and remove or alter the control flow in Of.


Second, FPGate is tested with two real world browsers, Firefox 3.6.16 (FF3) and Internet Explorer 6 (IE6)1.

the core modules xul.dll in FF3 and mshtml.dll in IE6 are hardened by FPGate, and other modules are left intact.


Assuch,arobustPUF createsa mathematicalfunctionthat is unique to each physical instance of a hardware design.

even if the same design is used for two devices, it is physicallyimpossibleto maketheirPUFsbehaveidentically.


The order in which the deletions take place is relevant when testing Equation 4.

deleting a role exclusivelya.ectsthecostofdirectparents and children.


In view of the aforementioned discussion, the aim of the present article is to characterize the e.ect of adversarial actions on the sensor and control data on the performance of the canal system.

we aim to a) Investigate the stealthy deception attacks on sensor and control data that can disrupt the intended purpose of commonly used P and PI controllers by increasing water loss and decreasing operational e.ciency.


We converted malspec constraints to corresponding template constraints.

due to calling conventions, system-call arguments from the malspec were replaced with stack locations.


Figure 12 shows the breakdown of the client-cloud bandwidth cost.

about 2X (out of a total of ~ 2.6X) of the bandwidth cost is due to hiding whether the block is being read or written (i.e., fetching one block of data with 1X cost and writing one block of data with 1X cost).


MALWARE ANALYSIS AND CONTAIN-MENT Several di.erent strategies have been proposed in the state of the art to address the problem of network containmnent and the quality of the dynamic analysis.

the concept of quality refers to both the need to allow connectivity to external hosts (to expose the malware interesting behavior) and to the need to make the analysis process repeatable.


The module has same authority and responsibility as Kernel code.

the Unix Kernel module may destroy the Kernel like all Kernel codes or device driver.


We infer the response type for each SQL signature by examining all the responses, returned by SQL queries with the same signature and associate a .ag r with each signature to indicate its response type.

we transform the singular SQL response into a set of keyvalue pairs similar to the representation of session variables (e.g., $row[ id ], $row[ role ] in index.php).


Trust assumptions: We assume that the data owner and the service provider are trusted, and that the analyst is untrusted.

the programs supplied by the analyst may act maliciously and try to leak information.


4.3 Results In the study, AMNESIA achieved a perfect score: For both subjects, it was able to correctly identify all attacks as SQLIAs, while allowing all legitimate queries to be performed.

for the cases considered, AMNE-SIA generated no false positives and no false negatives.


Given a tree of qupits which is 2-good in both bases, the outputs of RI and D are the same.

this means that no changes made by cheaters to their shares can a.ect the outcome of D. Lemmas 3.1 and 3.2 show that there is essentially a unique state which will be recovered in the reconstruction phase when the receiver R is honest.


the untrusted code needs to be instrumented to prevent it from changing segments and/or jumping over the segment override pre.x to refer to the unintended segment.


n, where c is some integer positive constant.

corollary: if c = 1 then the injective knapsack vector A = (1, p, p2, , pn-1) is also dense.


¯ When k 2, the number of columns of H in the modi.ed approach is smaller than that in Algorithm CT, while the constraint set for each entry of x1 is still Xk, which is larger than X1, the constraint set for each entry of the unknown vector x¯in Algorithm CT.

compared with Algorithm CT, when k 2, our modi.ed approach decreases the dimension of the overdetermined ILS problem, while increases the ranges of part of the constraint sets.


THE ADDITIVITY OF INFORMATION COMPLEXITY In this section we will show that information complexity is additive.

the information complexity ofperforming two independent tasks is the sum of the information complexities of each individual task.


We have been focused on security as a collective practice [8].

we are concerned not with one person s action and another, but people doing security together.


We say that f satis.es displacement-indistinguishability if: .

i 1 = i = n P(yi = xi) = C(d) the obfuscation function should not allow an adversary to determine the location of the user with probability higher than C(d) for any given position response Gi.


Note that we were able to transform the original attack sequence into a modi.ed variant that would not trigger even a single mismatch but that would have a similarly harmful e.ect.

there was no need to take advantage of the fact that pH allows a few occasional mismatches without setting o. alarms: our attack would be successful no matter what setting is chosen for the pH locality frame count threshold.


set is a subset of the ARM instruction set and is in particular suit Table 1: ARM Registers Register Purpose r0 r3 Function arguments; function results r4 r11 Register variables (callee saved) r12 Scratch register r13 (sp) Stack Pointer r14 (lr) Link Register (subroutine return address) r15 (pc) Program Counter cpsr Control Program Status Register able for embedded systems which often suffer from greater memory restrictions as PCs.

the libraries libc and libwebcore which we use as the code base for our attack on ARM contain mainly THUMB instructions.


And later, if one of the deduplicated pages is modi.ed, a copy-on-write (COW) technique is used.

the page will be copied, and the write operation will take e.ect on the copied page.


This list of credentials is arranged such that for any two credentials ci and cj, cj can be de.ned in terms of ci if and only if j>i.

cList is arranged such that if one role depends on other roles, it is de.ned after its dependencies are de.ned.


For most users, security is not a task in itself.

managing their security is not a goal for users, and is often only incidental to their task at hand; consequently, their motivation to actively manage their security may be low at best.


In order to compare IG in a fair manner, we decided to select the top-n ranked features according to IG criterion which achieved lowest WErr rates, which happened to be the top-45.

we evaluated RF classi.cation models with top-n IG ranked features, for n = 1 ...46 (top47 excluded as it is the full features set), and the top-45 achieved the lowest WErr rates.


This reliability is essential for cloud storage but not possessed by the single-server setting.

the .rst trivial solution does not have this reliability.


Interestingly, this threat model was found to correspond well to reported vulnerabilities.

these relatively simple threat models have proven useful for experimentation.


We show here that a secure ABE directly gives a trace and revoke system.

we show a tracing algorithm for the broadcast system EBE above.


everyone in IT Management is an IT Employee (and therefore in IT Employees), and every member of Accounting, IT Employees and Human Resources is a member of Everyone.


Therefore our architecture will lower the barrier to conducting a privacy audit, directly a.ecting an organization s cost for compliance.

small organizations that do not have the infrastructure for a full privacy-audit may use a simple o.-the-shelf Consumer Agent that implements one of a set of standard policies.


Our parallel constructions in this paper are agnostic to the choice of these proof techniques.

we o.er a way to restructure any existing re-encryption mixnet architecture so as to parallelize it.


To maximize a Nym N s possinymity and minimize anonymity loss rate, while also limiting delays caused by unreliable users, we may wish to consider some members of N s current possinymity set to be more valuable than others: e.g., users who have remained online and participating reliably for a long period with at most a few brief o.ine periods.

a policy might apply an o.ine-time threshold as discussed above to limit loss rate, but apply di.erent thresholds to di.erent members of N s current possinymity set, giving longer, more generous thresholds to more valued users.


we have to sacri.ce convergence speed for resilience to attacks.


CloudSeal shouldpreservethee.ciency of contentdelivery network.

it is desirable for the network to store a single copy of encrypted content at each system state.


A path pat o a* i tern is a .nite string of edge patterns.

the set I is the set of all path patterns based on spatial identi.ers in I.


However, providing security services in wireless sensor networks is quite challenging due to the resource constraints on sensor nodes and the threat of node compromises.

it is usually impractical to establish keys between communicating sensor nodes using traditional methods such as public key cryptography and key distribution centers (KDC).


x c-ce(g1,g2) e(T,g2) ß , e( x y Therefore, for A = T/h A, g W)= e(g1,g2)e(h, g2)- holds.


A source program P + is safe for G and A when P + is typable, polynomial, and all its declassi.cation labels are robust against A. Typability implies that, in a source program, no untrusted host is allowed to modify trusted variables, neither by modifying them directly, nor by calling a trusted host that modi.es high integrity variables.

for every locality a : S+ within P +, we must have rv(S+) .


We have also analyzed the limitations of policy migration.

an attacker may be able to .gure out whether policy migration happens, either by considering the semantics of a disclosed access control policy or by comparing policies for the same credential that were received during di.erent sessions of trust negotiation.


Users can change this setting by using a drop down menu.

the dialogue now offers the user control options directed towards the app developer as well as other users.


However, what if the impression count goes up arti.cially?

what if a third party was deliberately downloading ads, but not displaying them?


Malicious Code Suppose that the string returned by the call to adserver.com was: initSettings("evil.com"); When this string is passed to eval() and executed, it overwrites the page s settings.

it sets the variable searchUrl which is used as the pre.x of the query string, to refer to an attacker site evil.com.


Moreover, because of the decrease in the number of parameters and the parallel computation of (35), the running time reduces to just O(t).

the running time is proportional to the level of security.


Incorrect t| t = t (5) Accuracyt |Visiblet| and monitor for the event in which this ratio drops below the target value ß.

in the absence of predictions, Visiblet will grow over time as new accesses are exercised (and t incremented), thus causing (5) to drop below ß.


Finally, unmanaged data in.ltration can sometimes cause as many problems as data leakage.

the copyright of a software program is derived from the provenance of its constituent source .les.


In contrast, m-variate polynomials of total degree d `´ m+dd have d = O(m ) terms.

these two quantities seem incomparable as they crucially depend on the size of m vs. d. the PRFLW construction may not be suitable for this case.


Moreover, another useful property of LCS is to identify locationvariant features where the index values of i and j are not necessarily the same.

the location of the registered template feature can be at i while that of the query template at j.


CODE WITHOUT GADGETS Our goal is to provide a proactive solution to build gadget-free executables that cannot be targeted by any possible ROP attack.

we strive to achieve a comprehensive, transparent, and safe solution.


If a set C of t-m SMER constraints does not enforce a set E of k-n SSoD policies under PA and RH , then there exists a counter-example, i.e., a user-role assignment UA such that satis.esC((UA,PA, RH ))is true but safeE((UA, PA, RH ))is false.

there exists a k-n SSoD policy in E that is violated by k -1 users.


[0, 1] is a weight function that de.nes the edges of the graph.

the set of vertices in the graph is equal to the set of observed events by the adversary, i.e., V l = Ithere is a vertex in the graph Gl R|obs.


DEVICE MEMORY COLLISION ATTACKS In this section, we systematically examine how a VM can access the con.guration space of directly assigned devices, and what security risks are associated to these actions.

by recon.guring a device, an attacker can create a con.ict with another device.


Consequently, Extended-OPT offers the same security guarantee as IC-ING for the destination.

if the source is malicious, an illegitimate packet travels longer in Extended-OPT than ICING, but will be rejected by the destination.


For each node that has been matched, the node similarity is computed.

the user-user similarity for user nodes, the role-role similarity for role nodes, and the permission-permission similarity for permissions.


While these sensors enable a variety of new applications, they can also seriously jeopardize user privacy.

if a mobile device is compromised, an adversary can not only access the data stored in the device but also record all of the user s actions by stealthily sni.ng on the sensors.


However, if a line has two boxes, an unmarked one on the left and one marked Gi for some i on the right, then game Gj follows the box on the left for j<i and the box on the right for j = i.

the boxes on the right mark the differences from G0 introduced in some game, which are then adhered to in each subsequent game.


However, receivers may cache any received authentication information for future use.

receivers in DTNs are expected to retain authentication information as long as a connection to the neighboring sender is available and further bundle data is still incoming.


The challenges associated with evaluating intrusion detection systems, developing in- trusion detection metrics, and performing alert corre- lation and fusion are also discussed.

the speakers discuss their experience with designing, im- plementing, deploying, and evaluating a family of in- trusion detection systems [15, 5, 16].


There are of course alternatives to our de.nition of AEAD security.

one can use IND-CPA instead of IND$-CPA, eliminate the nonce and make encryption probabilistic, or eliminate the nonce and make encryption stateful.


When doing so, the resulting point P3 = 2P1 comprises .ve coordinates instead of four, which means P3 is actually represented in the form of a quintuple (X3 : Y3 : E3 : H3 : Z3).

the auxiliary coordinate T is split up into factors E and H so that EH = T = X Y /Z , thereby saving a multiplication in the point doubling.


While these approaches produce OPFs from speci.c subclasses of OPFD,R, Agrawal et al.

[1] were the .rst to uniformly draw OPFs from the complete set of OPFD,R.M = |D| numbers are drawn uniformly at random from R = {1,...,N}.


8.1 is that the minimal performance degradation induced by the attacks in this paper o.ers little hope for detecting these attacks.

prior studies suggest that cross-tenant sidechannel attacks in cloud settings can induce signi.cant performance degradation in victim workloads, as was the case in, e.g., the attacks demonstrated by Zhang et al.


To support this, we modify Credo to support mapping certain I/O devices directly into an emancipated guest VM.

for our implementation we enable one form of I/O support: our current implementation uses a GPS sensor that attaches through a serial port, as a result we need to enable serial port I/O from an emancipated guest VM.


Since n ' = t,the values of g(x0),...,g(xn ' -1) are independent and uniform in [0,r] (and similarly for h).

g * and h * are independent and uniform in [0,r]n ' .


(cn, tn) for an instruction where the function ti transforms a state provided that the condition ci holds on that state.

.s:arm_state arm_next s = ValueState () ti(s) if ci(s).


In this paper, we discuss the general problems of e-health systems and provide a technical solution for the protection of privacy-sensitive data, which has not been appropriately addressed yet for end-user systems.

our contributions are as follows: We describe an abstract model of e-health clouds (Section 2), which comprehends the common entities of healthcare telematics infrastructures.


Distributed Rule Evaluation As the number of context sensors on the phone and infrastructure increases, the sensing and data transfer cost increases.

we must optimize for the battery  drainage on the phone caused by Sensing on the phone and Data transfer between the infrastructure and the phone Cost Based Rule Evaluation With each predicate, we associate a cost of sensing and a cost of network transfer.


Amore active approach to study botnets is via in.ltration.

using an actual malware sample or a client simulating a bot, researchers join a botnet to perform analysis from the inside.


For all of those except publish app activity to Facebook, Null Hypothesis 2, that respondents ability to identify which write permissions they are authorizing is no di.erent than if they were randomly guessing, can be rejected with p < .01.

for these six permissions, people would have been signi.cantly more likely to correctly identify whether they were granting the permission by randomly guessing.


We note that a spline over two control points reduces exactly to that of Equation 7 and thus the results on unbounded tightness applies to spline based value functions as well.

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


Afterward, you both have to remember to "turn it all off" -to change your security settings back again.

for each task-oriented action, the user must perform one or more manual steps to manually mirror those application goals in terms of operating system security set- tings.


This further confirmed our already obtained insights into the possibly existing unwanted relationships between such components.

we had already observed at a formal level [5] that delegation and revocation features may be used to circumvent separation of duty properties, thus providing potentially undesired access to resources.


walking pattern) enjoys Equal Error Rate (EER) close to 7% [16].

the performances of walking patterns recog Table3:Parametersfor methods comparison.


INTRODUCTION Innovations in cars are mainly driven by electronics and software today [6].

graphical functions and applications enjoy growing popularity as shown by the increasing number of displays integrated into cars.


She sends a pseudonym along with her request, and the server responds with the requested page encrypted in such a way that she can only decrypt it if she has a doctor or patient credential issued against that pseudonym.

the server constructs the public keys corresponding to the secrets Alice has been issued if she is a certi.ed doctor and a certi.ed AIDS patient.


Each natural adversary may both actuate network components and modify the network s interaction topology (in permanent or temporary ways).

the dynamics can be viewed as being modified to .


It then had to be signi.cantly rewritten by Sun engineers to accomodate other TPMs.

the initialization functionality of the driver had to be entirely rewritten to make the driver compatible with the various TPMs that Sun developers added support for.


We propose a systematic black-box approach to identifying logic .aws within web applications.

we give a formalization of logic vulnerability based on the FSM model and present two test input generation methods.


A measure µ of the utility of a privacy mechanism must respect the generality partial order .G.

µ(M) = µ(A. M) for any randomized algorithm whose input space is the output space of M. 3.2 Measures of Generality In this section, using Axiom 3.1.4, we examine some candi date measures of utility.


When a con.ict occurs in a .rewall, the existing .rst matching rule may not be a desired rule that should take precedence with respect to con.ict resolution.

the existing .rst matching rule may perform opposite action to the rule which should be considered to take precedence.


Usually, the business activity tree can be provided by business sta..  Once activity-spread and organization-unit-spread indices are de.ned, we propose to adopt our cost-driven approach (see Section 3.2) to take them into account during the role mining process.

leveraging the cost function concept makes it possible to combine such indices with other cost elements in a single metric (function) to be used for the evaluation of elicited roles during the role mining process.


Thus, ROKs incorporate some unpredictable element that does not exist in traditional Turing machines: the history of prior machine executions.

for any given machine T , only the .rst execution (assuming either the encrypt or decrypt primitive is executed) will use the transitions de.ned by d. The second (and subsequent) executions will use d ' , as the state after the primitive is invoked will di.er.


However, because we cannot anticipate all such attacks, we have designed SybilQuery to support an extensible architecture.

it can incorporate several statistical features in its algorithm to generate Sybil paths, thereby making   Figure 1: Basic design of SybilQuery.


3 Alias Address Generation 4.2.2 Pseudonym Options The algorithm explained in 4.2.1 creates anonymous addresses.

even an employee of the ESP or a supplier cannot identify a customer from an alias address.


Within the same Ethernet broadcast domain, either all computers receive a broadcast message, or none of them receive it.

no dishonest receiver can receive a broadcast message while preventing an honest receiver from receiving it.


In order to enforce the security requirements in the Jif source code, information .ows between the client and the server must be strictly controlled.

con.dential information must not be sent to the client, and information received from the client cannot be trusted.


To mitigate the problem, we make special provisions for array handling.

if an element of an array is modi.ed within the body of a conditional statement with private condition and that assignment is not surrounded by a loop, the element of the array is treated as an ordinary variable, i.e., only a copy of the element is made, not a copy of the array.


However, Kirin does not track data .ows inside an application; thus, its analysis is necessarily less precise than ours.

for an application that has several components, each of which require a disjoint set of permissions, Kirin conservatively considers the union of those permissions when deciding the safety of the application.


The key-gate:-; Kl a.ml K3 converge at the ga.te G6, hence they are eonverging key-gates.

they are sequentially convergent; K3's effect cannot be muted while Kl 's effect can be rnut.ed by applying 15=0.


A delegation dj is dependent on a delegation di if all support chains for dj contain di.

dj is dependent on di if di is the only reason the grantor of dj received the rights that allowed her to make the delegation dj .


From the point of view of mobile privacy, the advantage of Facebook over other popular social networking mobile applications, such as Twitter, is that Facebook allows more varied activities and interactions and the content exchanged between users during these interactions.

facebook is a good example of the sort of virtual social environment in which or through which the complexity of mobile privacy issues is likely to manifest itself.


The Regularity Principle of Self-Management Naftaly Minsky Department of Computer Science, Rutgers University Piscataway, NJ 08854 USA minsky@cs.rutgers.edu ABSTRACT The principle of regularity proposed here for self management of systems, states that foralargesystem tobemanageable it must possess suitable regularities.

this principle identi.es the ability to establish regularities in asystem, as a necessary condition for its self-manageability.


Mobile storage devices are regularly employed to store copies of documents that the user (e.g., a doctor) may take home or to another o.ce, or data to be processed on other systems.

uSB disks are frequently used o.ine, i.e., plugged to any platform while it is not connected to the domain network (e.g., a laptop in the train or on an airplane).


To counter the soaring growth of spam volume, many ISPs have adopted the policy of blocking port 25 (SMTP port), in which outbound email from a subscriber must be relayed by the ISP-designated email server.

the ISP s edge routers only forward the SMTP tra.c from some designated IP addresses to the outside.


The CPA logic is designed to ensure that if Fp c * : fis derivable, then the probability of fin the experiment CPA(c * ) is upper bounded by pplus a negligible term.

if F1/2 c * : Guess is derivable, then any scheme .


Once a SLOC count is known, effort and scheduling equations are derived.

the embedded mode of COCOMO and REVIC are the most applicable for the software costing of an embedded digital system, e.g., the digital camera considered in this paper (Section 4).


To maintain the generality of SAAM, the decision element of the response tuple may take a number of di.erent values apart from the standard responses of allow and deny.

a decision may return an undecided response to indicate that a response could not be computed.


Since the results that can be obtained by this method are bounded both on the lower side (0%) and on the upper side (100%), no processing is performed for the training set.

instead of using a maximum allowed distance that is dependent on the training set (as done for DTW-D), for DTW-S we only use a maximum accepted threshold ßS .


Table 1: A brief comparison among (T)OAKE, HMQV and KEA KA = KB involves only a single hashing, where the output length of h, i.e., l, is set approximately to be |q|.For applications where g ab-traceability takes priority over HP Ab+yXb+ey Ba+xY a+ex deniability, we set KB = = = KA , which is referred to as traceable OAKE (T-OAKE, in short).

the value g ab can simply get involved (for applications where traceability takes priority over HP-deniability) at the minimal cost of only one modular addition, which eases more .exible and modular deployments in practice.


To validate the signature, at least k members of the con.rmer group form a legitimate con.rming group , cooperate to provide the validity proof.

there is a signing combiner whose task is to choose and encrypt some random values, compute the commitments, and collect all partial results during the signing phase.


P and T if and only if there does not exist p .

p, t 1 * ,t * 2 and t 1 * ..(p), 2 .T * such that t * =t * 1 t2 * ..(p) a generalization is non-overlapping when a real tuple can match at most one generalized tuple.


[1, 8)}: It follows from the computation of C(All),C(r),C(f1 Uf2),C(f1 nf2)that the characteristic set of any unit term f free of usersets and negations is {1}.

given a con.guration (U, UR) and a singleton {u1}such that {u1} satis.es f, we can make n -1copies of u1 for any n = 2so that the n users together satis.es f+.f+ maybesatis.edby n users for any n =1.


processes can fork new processes, create new objects, change the labels of processes and objects, and read, write, and execute objects.a process with label P can: (i) fork a new process a(P); (ii) createa new object .


Hence, any user assigned to a role at least as senior as r can exercise permission p. This is analogous to the ability of a subject to read any object whose security label is dominated by that of the subject.5 In its simplest form, the *-property requires that the security label of a subject is no greater than that of any object to which the subject tries to write.

if a subject can write to an object, any subject with a lower security label can also write to that object.


O = ((S >> 16) ^ S) & 0xffff; O= O | O << 16; Here there are 32 · 31/2 = 496 two-bit patterns on O to determine; the only interesting ones are that bits i and i + 16 must be equal, for 0 = i = 15.


All passwords are identified properly and asked in a random order known to the attacker if he/she is currently attacking.

during an attack, the attacker knows the identities of the passwords and observes the order of passwords asked during the login session.


This suggests the idea of a negative representation, in which a set of data elements is represented by its complement set.

elements not in the original set are represented, and the data itself is not explicitly stored (i.e.


A local or distant adversary may notice that communication is taking place, but cannot correlate the user s or device s identity.

we are not trying to protect the communication participants from identifying each other.


An honest signer with private key (Ai,xi) generates a signature s =(r,T1,T2,c,sa,sx,sd) by following the signing algorithm described above.

the signer computes the generators u and v according to equation (2), so the veri.er uses the same generators.


Unfortunately, the techniques of [52, 19] assume a trusted dealer and, if implemented in a distributed manner, their key generation phase is likely to be communicationexpensive (resorting to generic multiparty secure computations).

they seem hardly compatible with a round-optimal DKG protocol.


For this purpose, it may be useful to decorate terms with additional type information, so that proof-checking can be as straightforward as possible.

such type information may help in applying the rule [BindM ] backwards with the rule in its present form, we have to guess A and s in order to .nd the  semantics of Simply Typed DCC is standard.


In the .rst, we measured the performance of the introspection layer.

we measured the rate at which memory could be copied from the monitored guest to the SVM.


O, the associated subgraph uniquely determines (up to multiplicative constant) the likelihood function Lo(i) de.ned as Lo(i)= PM(o|i).

the output space should be a restricted subset of likelihood functions.


We found an additional 498 instances of multiple sanitization that were super.uous.

sanitizer A was applied before sanitizer B, rendering sanitizer B super.uous.


Our study of setresuid() in prior work [12, 21] and the documentation for it in the three sys tems that support it [4, 5, 7] tells us that all of them specify the same semantics for it with respect to processes with and without appropriate privileges.

even where the speci.cations for the function s behavior may di.er, they do not di.er for success and failure conditions for a process with appropriate privileges, or for a process without appropriate privileges.


Additionally, the manipulation of the system call arguments introduces possible races and other vulnerabilities [15].

we believe that this con.ates the role of the sandbox, thereby achieving a middle ground between the two opposite goals of user-land permission containment and attack surface reduction, as explained in the previous paragraph.


This is more general than Facebook-style SNSs, in which the social network is a simple graph [17].

we denote by G(V, I) the set of all social networks de.ned over vertex set V andrelationindexset I.members of G(V, I) share the same vertex set V , but di.er only in the edges.


we specify an information-.ow property called data-.ow integrity (DFI), and present a static type systemthatcan enforceDFIonWindowsVista.Roughly,DFIprevents any .ow of data from the environment to objects whose contents are trusted.


If there is a safe disclosure sequence G=(C1,...,Ck,R) under the covering policies, then either there is also one under the original policies, or PC* is satis.ed by {C1,...,Ck}.

after Ck is disclosed in the sequence, it is safe for Alice to tel l Bob that she does not possess C*.


SECURITY COMPLIANCE FRAMEWORK & RESEARCH CHALLENGES The general framework for solving the security compliance problem is a four-step process.

given an IT system S and a new security requirement R, the following steps have to be completed in order to make system S compliant with requirement R: 1.


Thus, one solution to this problem would be to employ some form of irreversible state change in the usage mechanism for these certi.cates.

what we need is some form of trusted memory on Bob s machine (other than the untrusted and reversible hard disk) that is somehow changed irreversibly during the usage protocol, such that it would be infeasible for Bob to revert his machine to a previous state.


With the aid of a locking mechanism, it is possible to ensure atomic kernel operations.

requests for asynchronous termi- nation are deferred until the thread to be stopped has left the kernel.


ac is a set of values for every context concept c described by Access Context at request time.

ac = {v1 of c1 ,v2 of c2 , ..., vn of cn}, where {c1 ,c2 , ..., cn}is the set of context concept described by the Access Context.


For each module, we explored di.erent mechanisms and discussed their advantages and limitations.

we discussed several novel mechanisms, such as context awareness, that the mobile platform enables.


However, some problems had to be solved.

the WilmaGate system uses different DHCP lease time for unauthorized and authorized clients, while the IP address pool is not necessarily di.erent.


The second approach is to leverage dynamic analysis without the need of requiring the OS kernel source code.

dynamic analysis runs the target system on top of an emulator (e.g., QEMU [22]) and monitors every memory access to derive the hook access instructions.


PROXIMITY-BASED VISIBILITY In the previous sections we have considered the case in which the event visibility was only related to the space hierarchy.

whenever an event is de.ned, the administrator also de.nes the set of locations in which such an event is visible.


One of our chosen-ciphertext attacks exploits a novel interaction between WinZip s compression algorithm and the AE-2 encryption method.

although the underlying AES-CTR-then-HMAC-SHA1 core of AE-2 provably protects both the privacy and the integrity of encapsulated data, cf.


The application can choose which method to use for data exchange.

the shared memory method has better performance but may require more careful input sanitation.


The basic concepts are expressed as predicates that can be derived from properties of the state.

we regard the protection mechanisms to have failed when the attacker gains possession of the laptop: 1 2 3 failed is an institutional fact, whose presence in the institutional state indicates that the resource in this case the laptop is now held by a non employee.


Moreover, all the deployment points need not be decided before deployment; therefore, we can deploy nodes on an ad hoc basis.

we can move to any point, measure the current location, distribute keys to the node (according to the location and the pdf ), and deploy  1Actually, the area of selectable keys is slightly larger than the area of the possible resident points due to the in.uence Figure 6: Keys to be distributed to S of r, but for explanation purpose we ignore the di.erence.


These scanners were tested in our experiments on other con.guration .les of these applications.

we ran the scanner for Apache on a con.guration .le used by a major university s web server, which contained 1341 lines of settings.


2.2 GTRBAC The Generalized Temporal Role Based Access Control (GTRBAC) model is an extension of Temporal RBAC (TR-BAC) which is an RBAC extension to address temporal constraints.

gTRBAC model allows one to express periodic and duration constraints on roles, user-role assignments, and role-permission assignments.


Unlike secrecy, DFI cannot be enforced without runtime checks.

access checks play a crucial role by restricting untrusted processes that may run in the environment.


The system administrator can also take action prior to an alert be raised.

he/she can perform a vulnerability scan [38].