Learn More
—Vehicular ad hoc networks (VANETs) allow vehicle-to-vehicle communication and, in particular, vehicle-generated announcements. Provided that the trustworthiness of such announcements can be guaranteed, they can greatly increase the safety of driving. A new system for vehicle-generated announcements is presented that is secure against external and internal(More)
Error-correcting codes and matroids have been widely used in the study of ordinary secret sharing schemes. In this paper, the connections between codes, matroids, and a special class of secret sharing schemes, namely, multiplicative linear secret sharing schemes (LSSSs), are studied. Such schemes are known to enable multiparty computation protocols secure(More)
The fast growth of Radio Frequency IDentification (RFID) implies a deployment challenge, namely how to keep this technology scalable without renouncing security and privacy features. This paper focuses on combining tag privacy and scalability using the hash locks mechanism. Our contribution is twofold: (i) a cell-based architecture is proposed in which the(More)
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. Previously proposed threshold broadcast encryption schemes have ciphertexts(More)
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,(More)
In this paper, we propose some cryptographic techniques to securely set up a mobile ad-hoc network. The process is fully self-managed by the nodes, without any trusted party. New nodes can join the network and are able to obtain the same capabilities as initial nodes; further, each node can obtain a pair of secret/public keys to secure and authenticate its(More)
In secret sharing schemes a secret is distributed among a set of users P in such a way that only some sets, the authorized sets, can recover it. The family Γ of authorized sets is called access structure. Given such a monotone family Γ ⊂ 2 P , we introduce the concept of extended access structures, defined over a larger set P = P ∪ ˜ P, satisfying these two(More)