Nikolaos Argyropoulos

Security Requirements Engineering for Cloud Computing: The Secure Tropos Approach

Security is considered an important aspect of software systems, especially in the context of cloud computing. Nevertheless, current practices towards securing software systems fail to take into account security issues during the early development stages and also cannot properly address the unique characteristics and needs of the cloud environment. To address such issues, Secure Tropos was developed as a security-oriented requirements engineering approach, offering a modeling language and sets of diagrams which facilitate the elicitation and elaboration of security features for software systems. In this work, we introduce Secure Tropos by discussing its main concepts, their relations and the main diagrams used to capture the different aspects of a software system. SecTro, a CASE tool developed specifically for the creation and analysis of Secure Tropos diagrams, is used to model a case study as an illustrative example. Finally, future work on expanding the functionalities offered by Secure Tropos is discussed.

Eliciting Security Requirements for Business Processes of Legacy Systems

The modernisation of enterprise legacy systems, without compromises in their functionality, is a demanding and time consuming endeavour. To retain the underlying business behaviour during their modernisation, the MARBLETM framework has been developed for the extraction of business process models from their source code. Building on top of that work, in this paper we propose an integrated approach for transforming the extracted legacy process models into Secure Tropos goal models. Such models facilitate the elicitation of security requirements in a high level of abstraction, which are then incorporated back into the process models of the modernised systems as security features. Therefore high level models can be derived from legacy source code with minimal manual intervention, where security can be elaborated by non-technical stakeholders in alignment with organisational objectives.

Towards the derivation of secure business process designs

Security is a critical aspect of business processes that organisations utilise to achieve their goals. Current works on secure business process design mainly focus on annotating existing process models with security related concepts. Meanwhile, little attention is given to the rationale and the alignment of such security choices to high-level organisational security goals. To that end, a goal-to-process transformation approach, with a clear security orientation, is introduced, as part of a wider framework. This transformation process, presented through an illustrative example, uses Secure Tropos goal models as an input to create intermediate, security-annotated process skeletons. These can be then refined, through a series of manual tasks, to create secure BPMN process models.

Selecting Security Mechanisms in Secure Tropos

As security is a growing concern for modern information systems, Security Requirements Engineering has been developed as a very active area of research. A large body of work deals with elicitation, modelling, analysis, and reasoning about security requirements. However, there is little evidence of efforts to align security requirements with security mechanisms. This paper extends the Secure Tropos methodology to enable a clear alignment, between security requirements and security mechanisms, and a reasoning technique to optimise the selection of security mechanisms based on these security requirements and a set of other factors. The extending Secure Tropos supports modelling and analysis of security mechanisms; defines mathematically relevant modelling concepts to support a formal analysis; and defines and solves an optimisation problem to derive optimal sets of security mechanisms. We demonstrate the applicability of our work with the aid of a case study from the health care domain.

Supporting the design of privacy-aware business processes via privacy process patterns

Privacy is an increasingly important concern for modern software systems which handle personal and sensitive user information. Privacy by design has been established in order to highlight the path to be followed during a systems design phase ensuring the appropriate level of privacy for the information it handles. Nonetheless, transitioning between privacy concerns identified early during the systems design phase, and privacy implementing technologies to satisfy such concerns at the later development stages, remains a challenge. In order to overcome this issue, mainly caused by the lack of privacy-related expertise of software systems engineers, this work proposes a series of privacy process patterns. The proposed patterns encapsulate expert knowledge and provide predefined solutions for the satisfaction of different types of privacy concerns. The patterns presented in this work are used as a component of an existing privacy-aware system design methodology, through which they are applied to a real life system.

Attribute-Based Security Verification of Business Process Models

Business processes, as the instruments used by organisations to produce value, need to comply with a number of internally and externally imposed standards and restrictions. Since the majority of such processes involve the exchange of sensitive third party information, their compliance to security constraints needs to be verified before they can be implemented. Current attempts for the verification of security compliance of design-time business process models involve the transformation of both the model and the desired security properties into formal specifications, which can be then used as input for automated model checkers. Such an approach is usually costly both in terms of time and specialised knowledge, while also its coverage can be limited to specific types of security requirements. In this work we introduce an approach for the verification of security in business process models based on structural properties of the workflow of the process. To that end, we introduce a series of attributes to existing BPMN 2.0 concepts and algorithms for checking the compliance of a process model against the most common security requirements. Finally, a real-world business process is used to demonstrate and evaluate the applicability of our proposal.

Decision-Making in Security Requirements Engineering with Constrained Goal Models

Selecting security mechanisms for complex software systems is a cumbersome process. The presence of multiple goals and architectural components, as well as cost and performance considerations, render decision-making a crucial but complicated aspect of a system’s design. In our work, we extend Secure Tropos, a security requirements engineering methodology, by introducing the concept of Risk in order to facilitate the elicitation and analysis of security requirements and also support a systematic risk assessment process during the system’s design time. Next, we use Constrained Goal Models to reason about optimal security mechanism combinations with respect to multiple objectives of the system-to-be, taking into account conflicting functional and non-functional goals. This type of reasoning allows combining linear multi-objective optimisation with logical constraints introduced by the system’s stakeholders. Finally, we illustrate the application of approach through a real-world case study from the e-government sector.

Supporting Secure Business Process Design via Security Process Patterns

Security is an important non-functional characteristic of the business processes used by organisations for the coordination of their activities. Nevertheless, the implementation of security at the operational level can be challenging due to the limited security expertise of process designers and the delayed consideration of security during process development. To overcome such issues, expert knowledge and proven security solutions can be captured in the form of process patterns, which can easily be reused and integrated to business processes with minimal security-related knowledge required. In this work we introduce process-level security patterns, each of which contains the main activities required for the operationalisation of different security requirements. The introduced patterns are then used as a component of an existing framework for the creation of secure business process designs, the application of which, is illustrated through a working example. A preliminary evaluation of the proposed patterns is conducted via a workshop session.

Security Alignment Analysis of Software Product Lines

Context: Security is becoming increasingly important during software engineering. Software developers should be able to adapt and deploy secure systems in a continuously changing execution context. Method: We use Software Product Lines (SPLs), Business Process Management (BPM) and Security Requirements Engineering (SRE) techniques for anticipating the uncertainty and the changes of security requirements. Results: We provide a method to support developers to incorporate security in the design of SPLs systems. To avoid costly and extensive re-design of SPLs and BPs, we propose a methodology to analyse the strategic change impact of SPLs and BPs. The methodology supports the alignment of organizational strategy and execution level with an emphasis to security. Conclusions: This methodology constitutes a guideline to trace back the impact of change respecting security constraints of SPLs and BPs on different abstraction levels.