@booklet {259, title = {GS3: a Grid Storage System with Security Features}, journal = {JOURNAL OF GRID COMPUTING}, volume = {8}, year = {2010}, pages = {391{\textendash}418}, abstract = {Technological trend and the advent of worldwide networks, such as the Internet, made computing systems more and more powerful, increasing both processing and storage capabilities. In Grid computing infrastructures, the data storage subsystem is physically distributed among several nodes and logically shared among several users. This highlights the necessity of a) availability for authorized users only, b) confidentiality, and c) integrity of information and data: in one term security. In this work we face the problem of data security in Grid, by proposing a lightweight cryptography algorithm combining the strong and highly secure asymmetric cryptography technique (RSA) with the symmetric cryptography (AES). The proposed algorithm, we named Grid secure storage system (GS(3)), has been implemented on top of the Grid file access library (GFAL) of the gLite middleware, in order to provide a file system service with cryptography capability and POSIX interface. The choice of implementing GS(3) as a file system, the GS3FS, allows to protect the file system structure also, and to overcome the well-known problem of file rewriting in gLite/GFAL environments. In the specification of the GS3FS, particular care is addressed on providing a usable user interface and on implementing a file system that has low impact on the middleware. The final result is the introduction of a new storage Grid service into the gLite middleware, whose overall characteristics are never offered before, at the best of authors{\textquoteright} knowledge. The paper describes and details both the GS(3) algorithm and its implementation; the performance of such implementation are evaluated discussing the obtained results and possible application scenarios in order to demonstrate its effectiveness and usefulness.}, keywords = {Confidentiality, File system, GFAL, gLite, Grid, Integrity}, doi = {10.1007/s10723-010-9157-9}, author = {V. D. Cunsolo and S. Distefano and A. Puliafito and Marco Scarpa} } @booklet {270, title = {A Grid-based Algorithm For The Solution Of Non Markovian Stochastic Petri Nets}, journal = {CONCURRENCY AND COMPUTATION}, volume = {19}, year = {2007}, pages = {1353{\textendash}1370}, abstract = {WebSPN is a modeling tool for the analysis of non-Markovian stochastic Petri nets that we developed some years ago. Its solution algorithm is based on a discretization of time and an approximation of non-exponentially distributed firing time transitions by means of the phase-type distributions. In order to solve the problems related to the management of the state space (which can become very large) we parallelized the solution algorithm through the MPICH libraries. To improve the MPICH parallel implementation with an adequate security management, a more efficient load distribution and fault-tolerance capabilities, in this paper we propose the porting of WebSPN from the MPI to the Grid computational paradigm. In addition to a better flexibility in accessing computational and storage resources, one of the main advantages is the introduction of a fault recovery system to detect and recover from potential machine faults. The resulting new tool is named GridSPN.}, keywords = {DPH, Globus, Grid, MPI, MPICH-G2, non-markovian stochastic Petri net, parallel computation}, doi = {10.1002/cpe.1105}, author = {Marco Scarpa and A. Puliafito and S. Distefano} }