R. K. Shyamasundar

An efficient, secure and delegable micro-payment system

We propose a new efficient and secure micro-payment scheme, named e-coupons, which can provide the users the facility of delegating their spending capability to other users or their own devices like Laptop, PDA, Mobile Phone, and such service access points. The scheme has the promise of becoming an enabler for various Internet-based services involving unit-wise payment. We give flexibility to the users to manage their spending capability across various access points for a particular service without obtaining an authorization for each and every access point from a facilitating bank. This flexibility which is not present in the existing micro-payment schemes is essential for accessing ubiquitous e-services and other Internet-based applications. The facility of delegation introduces a slight overhead in respect of the proof or verification of the delegated authorization and security provided to the payments. The payoff from the facility of delegation takes away the burden of the overhead. We discuss the design of the protocol and provides a basic analysis of the performance of the system.

Trust management for e-transactions

There has been enormous increase in transactions and cooperative-computing services on the internet. This is both a technical and a social phenomenon. Transactions and services over the internet have global reach and users, known or unknown to the service provider, might be interested in availing access or participating in the cooperative transaction in a distributed manner. Thus, it is very important for service providers to identify and establish trustworthiness of potential collaborators, which they do by writing contracts (e.g. access control, security policies; the words contract and policy are used interchangeably) without violating the privacy and confidentiality laws that prevail across geographical boundaries. But as the system becomes complex and dynamic, contractual incompleteness arises since it becomes cumbersome to mention potentially large set of outcomes of the users choice of action. Trust plays a crucial role in the design of optimal contracts; not all the relevant, valuable information on the users choice of action is incorporated in the equilibrium contract. It may also be noted in that traditional transactions, the notion ofseeing is believing plays a vital role. However, in e-transactions, this is not the case. The challenge is to see how in such a scenario trust can indeed be generated. Note that the presence of trust facilitates cooperative behaviour and allows for exchange to occur in situations where its absence would preclude trade. In this paper, we shall present a comparative analysis of various approaches of trust management in practice that integrates technology with other factors. We shall also bring out the relative deficiencies and how these issues are tackled in our ongoing work that facilitates execution of optimal contracts.

Privacy as a Currency: Un-regulated?.

We are living in a time where many of the decisions that affect us are made by mathematical models. These models rely on data. Precision and relevance of the decisions made by these models is dependent on quality of the data being fed to them. Therefore, there is a rush to collect personal data. Majority of the organizations that provide online services are at the forefront of collecting user data. Users, either voluntarily or by coercion, divulge information about themselves in return of personalized service, for example. These organizations’ revenue model is based on advertisement where advertisers are paired with user profiles that are built on top of collected data. This data is being used for a variety of purposes apart from delivering targeted advertisements. Mathematical decision models are impartial to the data on which they operate. An error, omission or misrepresentation in data has an irrevocable consequence on our lives, at times, without corrective remedies. This paper touches upon various facets of information gathering; information bias, economics of privacy, information asymmetry – and their implications to our ecosystem if left unaddressed.

Design of software for safety critical systems

In this paper, we provide an overview of the use of formal methods in the development of safety critical systems and the notion ofsafety in the context. Our attempt would be to draw lessons from the various research efforts that have gone in towards the development of robust/reliable software for safety-critical systems. In the context of India leaping into hi-tech areas, we argue for the need of a thrust in the development of quality software and also discuss the steps to be initiated towards such a goal.

Compositional priority specification in real-time distributed systems

In this paper, we develop a compositional denotational semantics for prioritized real-time distributed programming languages. One of the interesting features is that it extends the existing compositional theory proposed by Koymanset al (1988) for prioritized real-time languages preserving the compositionality of the semantics. The language permits users to define situations in which an action has priority over another action without the requirement of preassigning priorities to actions for partially ordering the alphabet of actions. These features are part of the languages such as Ada designed specifically keeping in view the needs of real-time embedded systems. Further, the approach does not have the restriction of other approaches such as prioritized internal moves can pre-empt unprioritized actions etc. Our notion of priority in the environment is based on the intuition that a low priority action can proceed only if the high priority action cannot proceed due to lack of the handshaking partner at that point of execution. In other words, if some action is possible corresponding to that environment at some point of execution then the action takes place without unnecessary waiting. The proposed semantic theory provides a clear distinction between the semantic model and the execution model — this has enabled us to fully ensure that there is no unnecessary waiting.

Computer Science: Reflection and Future

*Author for Correspondence: E-mail: shyamasundar@gmail.com 1The question posed was: Is it possible to have a method that takes a proposition in first-order logic as input which will decide in a finite number of well-defined steps, whether the proposition is true or not? 2Note that by establishing that there is no complete and consistent set of axioms for all of mathematics, Godel shattered the dream of Bertrand Russell and A. N. Whitehead. Proc Indian Natn Sci Acad 84 No. 2 June 2018 pp. 339-357  Printed in India. DOI: 10.16943/ptinsa/2018/49337

Validation and analysis of the futurebus arbitration protocol: A case study

In this paper, we use perfectly synchronous languages such asEsterel, for modelling Futurebus arbitration protocol. We show that the perfect synchrony aids in the formalization, testing, validating and verifying the protocol. We discuss solutions to the above protocol and show that properties such as mutual exclusion and deadlock-freedom can be established formally. Further, we show how the simulators can be used for testing and validation and can verify an instantiation of the protocol through algebraic tools such as auto/autograph.

Modelling real-time systems: issues and challenges

In this paper, we discuss the issues and challenges that lie in the specification, development, and verification of real-time systems. In our presentation, we emphasize on the issues underlying modelling of real-time distributed concurrency.