Clerici, S.I.; Zoltan, A.; Prestigiacomo, G. Electronic notes in theoretical computer science Vol. 258, num. 1, p. 93-107 DOI: 10.1016/j.entcs.2009.12.007 Data de publicació: 2009-12-25 Article en revista
NiMo (Nets In Motion) is a Graphic-Functional-Data Flow language designed to visualize algorithms and their execution in an understandable way. Programs are process networks that evolve showing the full state at each execution step. Processes are polymorphic, higher order and have multiple outputs. The language has a set of primitive processes well suited for stream programming and supports open programs and interactive debugging. The new version of the environment NiMo Toons includes: an also graphic and incremental type inference system, multiple output processes as higher order parameters, symbolic execution, five evaluation modes that can be globally or locally set for each process and dynamically changed, and facilities to measure the used resources (parallelism level, number of steps, number of processes, etc.)
Daza, V.; Herranz, J.; Morillo, M.; Rafols, C. Electronic notes in theoretical computer science Vol. 192, num. 2, p. 3-15 DOI: 10.1016/j.entcs.2008.05.002 Data de publicació: 2008-05 Article en revista
In a threshold broadcast encryption scheme, a sender chooses (ad-hoc) a set of n receivers and a threshold t, and then encrypts a message by using the public keys of all the receivers, in such a way that the original plaintext can be recovered only if at least t receivers cooperate.
This kind of scheme has many applications in mobile ad-hoc networks, characterized by their lack of infrastructure as well as for the high dynamism of their nodes. Threshold broadcast encryption schemes are much more appropriate for mobile ad-hoc scenarios than standard threshold public key encryption schemes, where the set of receivers and the threshold for decryption must be known in advance (and remain the same for the rest of the protocol).
Previously proposed threshold broadcast encryption schemes have ciphertexts which contain at least n group elements. In this paper, we propose a new scheme where the ciphertexts contain essentially n-t group elements. The construction uses secret sharing techniques and the ElGamal public key cryptosystem as basic tools. We formally prove the security of the scheme, by reduction to the security of ElGamal cryptosystem.
Identity-Based cryptography has been proposed in mobile ad-hoc networks (MANETs) to provide security. However, the figure of the Private Key Generator (PKG) is not adequate in the MANET setting, since it may not be reachable by all nodes, can fail during the life-time of the protocol or can even be attacked, compromising the whole system. Previous works distribute the task of the PKG among a set of nodes by means of a secret sharing scheme.
In this paper we propose an efficient solution to emulate in a dynamic and distributed way the role of the PKG in so that even new nodes joining the network are able to issue shares of the master key of an Identity-Based scheme. In this way, the distributed PKG spreads dynamically among the nodes as the network increases. Furthermore, the techniques we propose may be suitable for other protocols over MANETs.