The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

A system and method for communicating information between a first party and a second party, comprising the steps of receiving, by an intermediary, an identifier of desired information and accounting information for a transaction involving the information from the first party, transmitting an identifier of the first party to the second party, and negotiating, by the intermediary, a comprehension function for obscuring at least a portion of the information communicated between the first party and the second party. The data transmission may be made secure with respect to the intermediary by providing an asymmetric key or direct key exchange for encryption of the communication between the first and second party. The data transmission may be made secure with respect to the second party by maintaining the information in encrypted format at the second party, with the decryption key held only by the intermediary, and transmitting a secure composite of the decryption key and a new encryption key to the second party for transcoding of the data record, and providing the new decryption key to the first party, so that the information transmitted to the first party can be comprehended by it.

System and method for secure three-party communications

This review describes a body of work on computational immune systems that behave analogously to the natural immune system. These artificial immune systems (AIS) simulate the behavior of the natural immune system and in some cases have been used to solve practical engineering problems such as computer security. AIS have several strengths that can complement wet lab immunology. It is easier to conduct simulation experiments and to vary experimental conditions, for example, to rule out hypotheses; it is easier to isolate a single mechanism to test hypotheses about how it functions; agent-based models of the immune system can integrate data from several different experiments into a single in silico experimental system.

Computer immunology

In "Grids" and "collaboratories," we find distributed communities of resource providers and resource consumers, within which often complex and dynamic policies govern who can use which resources for which purpose. We propose a new approach to the representation, maintenance, and enforcement of such policies that provides a scalable mechanism for specifying and enforcing these policies. Our approach allows resource providers to delegate some of the authority for maintaining fine-grained access control policies to communities, while still maintaining ultimate control over their resources. We also describe a prototype implementation of this approach and an application in a data management context.

A Community Authorization Service for Group Collaboration

Modern distributed systems contain a large number of objects and must be capable of evolving, without shutting down the complete system, to cater for changing requirements. There is a need for distributed, automated management agents whose behavior also has to dynamically change to reflect the evolution of the system being managed. Policies are a means of specifying and influencing management behavior within a distributed system, without coding the behavior into the manager agents. Our approach is aimed at specifying implementable policies, although policies may be initially specified at the organizational level and then refined to implementable actions. We are concerned with two types of policies. Authorization policies specify what activities a manager is permitted or forbidden to do to a set of target objects and are similar to security access-control policies. Obligation policies specify what activities a manager must or must not do to a set of target objects and essentially define the duties of a manager. Conflicts can arise in the set of policies. Conflicts may also arise during the refinement process between the high level goals and the implementable policies. The system may have to cater for conflicts such as exceptions to normal authorization policies. The paper reviews policy conflicts, focusing on the problems of conflict detection and resolution. We discuss the various precedence relationships that can be established between policies in order to allow inconsistent policies to coexist within the system and present a conflict analysis tool which forms part of a role based management framework. Software development and medical environments are used as example scenarios.

Conflicts in policy-based distributed systems management

ly speaking, the law Lof a policy is a functionthat returns a ruling for every possible regulated-event thatmight happen at a given agent. The ruling returned by thelaw is a possibly empty sequence of primitive operations,which is to be carried out locally at the location of the eventfrom which the ruling was derived (called the home of theevent). (By default, an empty ruling implies that the eventin question has no consequences—such an event is eﬀectivelyignored.)Concretely, under the Moses implementation of LGI, thelaw is deﬁned by means of a Prolog-like program 3 Lwhich,when presented with a goal e, representing a regulated-eventat a given agent x, is evaluated in the context of the control-state of this agent, producing the list of primitive-operationsrepresenting the ruling of the law for this event. Beforeintroducing the structure of such laws we deﬁne the types ofevents that are regulated by laws under Moses, the structureof an agent’s control-state, and the primitive operations thatcan be included in the ruling of a law.The Regulated Events:The events that are subject to thelaw of a policy are called regulated events. Each of theseevents occurs at a certain agent, called the home of theevent. The following are two of these event-types.1. sent(x,m,y)—occurswhen agent xsends an L-messagemaddressed to y. The sender xis considered the homeof this event.2. arrived(x,m,y)—occurswhen an L-message msent byxarrives at y. The receiver yis considered the homeof this event.The Control State: The control-state CS

Making tuple spaces safe for heterogeneous distributed systems

Given a certain class C of reconfigurations, deemed to be potentially important for a given system, we define a reconfiguration suite S/sub c/ to be a set of primitive operations that satisfy the following conditions: any reconfiguration in C can be carried out by a sequence of primitives from S/sub c/. The correctness of S/sub c/ should be independent of the functionality of the system, and invariant of its reconfigurations (for a given set of possible configurations of the system at hand). We describe a mechanism for implementing such reconfiguration suites, for a system that operates under law-governed interaction (LGI), currently supported by an experimental toolkit called Moses. LGI is a mode of interaction between the members of a given group (or system) of agents, which is governed by an explicit and strictly enforced set of rules, called the law of this group. The existence of such a law under LGI provides us with an architectural model of the system, which can be made to include the definition of reconfiguration suites.

Building reconfiguration primitives into the law of a system

Effective load balancing for cluster-based servers employing job preemption

Conventional mechanisms for electronic commerce provide strong means for securing transfer of funds, and for ensuring such things as authenticity and non-repudiation. But they generally do not attempt to regulate the activities of the participants in an e-commerce transaction, treating them, implicitly, as autonomous agents. This is adequate for most cases of client-to-vendor commerce, but is quite unsatisfactory for inter-enterprise electronic commerce. The participants in this kind of e-commerce are not autonomous agents, since their commercial activities are subject to the business rules of their respective enterprises, and to the preexisting agreements and contracts between the enterprises involved. These policies are likely to be independently developed, and may be quite heterogeneous. Yet, they have to interoperate, and be brought to bear in regulating each e-commerce transaction. This paper presents a mechanism that allows such interoperation between policies, and thus provides for inter-enterprise electronic commerce.

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Establishing Business Rules for Inter-Enterprise Electronic Commerce

Linda is a high-level coordination model that allows agents to interact via shared tuplespaces without knowing each other's identities and without having to arrange for a definite rendezvous. This high level of abstraction would make Linda particularly suitable for use as a coordination model for heterogeneous distributed systems, if it were not for the fact that the Linda communication is unsafe. In order to enhance the safety of tuplespaces, this article introduces a mechanism for establishing security policies that regulate agent access to tuplespaces. This mechanism is based on a previously published concept of law-governed interaction. It makes a strict separation between the formal statement of a policy, which one calls a "law," and the enforcement of this law, which is carried out by a set of policy-independent trusted controllers. A new policy under this scheme is created basically by formulating its law, and can be easily deployed throughout a distributed system. Two example policies are discusse...

/pdf/safe-tuplespace-based-coordination-in-multiagent-systems-2ique68to5.pdf

Victoria Ungureanu

Papers

Making tuple spaces safe for heterogeneous distributed systems

Building reconfiguration primitives into the law of a system

Effective load balancing for cluster-based servers employing job preemption

Establishing Business Rules for Inter-Enterprise Electronic Commerce

Safe tuplespace-based coordination in multiagent systems