Previous Work. ARTS Staff continued work on monitoring current complete street policies and regulations.
Previous Work. Reputation mechanisms are being used to increase the reliability and perfor- xxxxx of virtual societies (or organisations) while providing mechanisms for exchanging reputation values. In centralised reputation models, a reputation system receives feedback about the interactions among the agents. Each agent evaluates the behaviour of the agents with whom it interacts and informs the reputation system. The system puts together all evaluations and stores such rep- utations. In contrast, in distributed reputation models, each agent evaluates and stores the reputations of the agents with whom it has interacted with and is able to provide such information to other agents. With the aim to cope with the problems of centralised and distributed rep- utation mechanisms3, we proposed the use of a hybrid mechanism [12]. In the distributed part of such a mechanism, agents evaluate the behaviour of other agents by exchanging opinions and storing such information. An opinion has to be justified by providing, for instance, the set of violated norms that contribute to that opinion. This work is framed in organisational environments that provide a minimum set of organisational mechanisms to regulate agents’ interactions. Formally, an organisation is defined as a tuple g, , , φ, x0, ϕ, om, om where g represents the set of agents participating within the organisation; is the set of actions agents can perform; stands for the environmental states space; φ is a function describing how the system evolves as a result of agents actions; x0 represents the initial state of the system; ϕ is the agents’ capability function describing the actions agents are able to perform in a given state of the environ- ment; om is an organisational mechanism based on organisational norms; and om is an organisational mechanism based on roles that defines the positions agents may enact in the organisation (see [5] for more details). Agents participating in the field of such organisations are involved in different situations. A situation is defined as a tuple g, , , T , that represents an agent g, playing the role , while performing the action , through a time period T . As detailed in [5], different types of situations can be defined following this definition. For instance, situations in which an agent performs an action, regardless of the role it is playing – g, , , –, or situations in which an agent is playing a role along a time period, regardless the action it performs –
Previous Work. Broadcast: For the standard communication model with a complete synchro- nous network of pairwise authenticated channels, Pease, Shostak, and Xxx- port [PSL80] proved that perfectly secure broadcast is achievable if and only if less than a third of the players is corrupted: t < n/3. This tight bound more generally holds with respect to a network of secure channels and unconditional security, i.e., when even allowing a negligible error probability, as proven by Xxxxxx and Xxx [KY]. The first optimally resilient protocol that is efficient was proposed by Xxxxx et al. [DFF+82]. For the case that broadcast among ev- ery subset of three players is possible (in contrast to the standard model with only pairwise communication), Fitzi and Xxxxxx [FM00] proved that (global) broadcast is possible if and only if t < n/2. In another line of research, Xxxx- Xxxxxxx, Xxxxxxxxx, and Xxxxxxx [BPW91,PW92] proved that broadcast during some precomputation stage allows to later achieve broadcast that tolerates any number of corrupted players (t < n), i.e., that the functionality of the prior broadcast can be preserved for any later time. Multi-party computation: The concept of general multi-party computation (MPC) was introduced by Xxx [Yao82] with a first complete solution given by Goldreich, Xxxxxx, and Xxxxxxxxx [GMW87] – though with computational se- curity. Ben-Or, Xxxxxxxxxx, and Xxxxxxxxx [BGW88], and, Xxxxx, Xx´epeau, ⊥ 1 That is, interpreting as “invalid”, this condition expresses that no two correct players may decide on valid values that are distinct. and Damg˚ard [CCD88], proved that, in the standard model with pairwise se- cure channels, unconditionally secure MPC is achievable if and only if t < n/3 by giving efficient protocols for the achievable cases. Beaver [Bea89], and inde- pendently, Xxxxx and Xxx-Or [RB89] later proved that, when additionally given global broadcast among the players, unconditionally secure MPC is achievable if and only if t < n/2 (see also Xxxxxx et al. [CDD+99]). The result in [FM00] hence implies that broadcast among three players (i.e., 2-cast) is sufficient in order to achieve MPC for t < n/2.
Previous Work. Compiled the most current crash data for Aiken, Columbia, Edgefield, and Richmond Counties.
Previous Work. Continued assessment of the financial capability of AT and secure other possible funding sources to implement recommendations from the COA.
Previous Work. Development and adoption of the FY 2024-2027 (GA) & FY 2024-2033 (SC) TIP by November 16, 2023.
Previous Work. Digital and hard-copy maps were created for use in transportation planning and analysis, internal and external meetings, and reports.
Previous Work. Grant management for continuing FTA Section 5310 Enhanced Mobility for the Elderly and Disabled Persons for LSCOG.
Previous Work. Updating ARTS 2050 MTP based on amendments, performance targets, financial constraint analysis, and newly identified transportation projects and programs.
Previous Work. In 2006 [1] in joint work with X. Xxxxxx and X. Xxxxxxx two of us (IA and DG) introduced a key agreement protocol based in group theory (specifically the braid group) that has withstood several attacks over the past decade. First Myasnikov–Ushakov [20] determined that if braids are too short then one can find the conjugating factor and use that to break the system. However it was pointed out by one of us (PG) [14] that in practice the braids are long enough that this attack can never succeed: the method in [20] is analogous to using Fermat’s technique to factor short RSA keys, which becomes impractical at secure sizes. Second, Kalka–Xxxxxxx–Tsaban [16] described a linear algebra attack (KTT) that would allow an attacker to determine part of the private key data. However, two of us (DG and PG) [12] showed that this attack succeeds only on a class of weak keys, and that choosing the private key data more carefully defeats this attack. Subsequent to the KTT attack, Xxx-Xxx–Xxxxxxxxx–Tsaban [7], using all of the available public information of the protocol, were able to reconstruct the shared secret, after a large precomputation and several hours of runtime. We later showed [2] that the work necessary to carry out the attack increases as the size of the permutation order grows as well as the size of the braid group. We remark that the current review of WalnutDSA [3], a group theoretic based digital signature, does not apply to the Ironwood protocol. In particular the (exponential) attack on reversing E-multiplication requires data not available to an attacker, and hence the underlying hard problems considered in these approaches do not impact the Ironwood security (see §VI).
