Abstract: A method for managing a group signature scheme includes in a setup procedure for group initialization, generating, by a group manager, a group public key. In a join procedure for the group manager to add a new member to the group, the method includes generating by the new member, user information, and providing the generated user information to the group manager, and computing, by the group manager, membership information for the new member based on the user information received by the new member and on the group public key, and providing to the new member the computed membership information. In particular, the membership information is computed, by the group manager, as a function of the inverse of a given hash function of the user information. In a signing procedure for a group member to sign a message on behalf of the group, the method includes: using, by the group member, the membership information and the user information.

Abstract: A method for managing a group signature scheme includes in a setup procedure for group initialization, generating, by a group manager, a group public key. In a join procedure for the group manager to add a new member to the group, the method includes generating by the new member, user information, and providing the generated user information to the group manager, and computing, by the group manager, membership information for the new member based on the user information received by the new member and on the group public key, and providing to the new member the computed membership information. In particular, the membership information is computed, by the group manager, as a function of the inverse of a given hash function of the user information. In a signing procedure for a group member to sign a message on behalf of the group, the method includes: using, by the group member, the membership information and the user information.

Abstract: A system for enabling a user to communicate on a virtual private network through a public communication network, the possibility of communicating on the private network depending on the availability to the user of at least one enabling credential sent to the user in encrypted form. The system includes at least one SIM type module available to the user and bearing an encryption mechanism and it is configured to decrypt the enabling credential at the user exploiting the encryption mechanism home by the SIM type module, the SIM type module being able to interact with at least one additional communication network to activate the encryption mechanism.

Abstract: A system includes a sending terminal and at least one receiving terminal, the terminals capable of being connected to a communication network for transmitting an information item from the sending terminal to the at least one receiving terminal. The sending terminal is linked via a secure channel to a unit adapted to encrypt sensitive data using a first encryption/decryption mechanism, the sensitive data being used to protect the information item, and the at least one receiving terminal capable of interacting with a SIM module storing a second encryption/decryption mechanism identical to the first encryption/decryption mechanism, for decrypting the sensitive data.

Abstract: An arrangement for the cipher controlled exploitation of data resources (e.g., securely storing and retrieving sensitive data or securely registering and logging on a computer system) includes the steps of providing a subscriber identity module carrying a security algorithm; generating at least one, e.g., two, random values; subjecting the random value to the at least one security algorithm to generate at least one, e.g., two, session keys; processing the session keys via a mixer function such as a hash function to produce a cipher key; and using the cipher key thus produced for exploiting the data resources.

Abstract: Communication between an administrator device and an administered device in a network is arranged in the form of a chain of digitally signed communication items including messages sent from an originator device to a recipient device. Each message has an associated respective digitally signed receipt, and the originator device is configured not to send a new item toward the recipient device in the absence of a respective digitally signed receipt for a previously sent item. With at least one, and preferably by both of the administrator device and the administered device, there is stored a history record of communication items exchanged therebetween. The history record is agreed upon and signed by both the administrator device and the administered device.

Abstract: A method for securely storing at least one user's private information item, such as a private key for cipher processing, includes the steps of providing a communication network wherein the user is allotted a respective subscriber identity module and the subscriber identity module stores at least one security algorithm; producing a cipher key via the at least one security algorithm; and providing a remote storing location accessible by the user via the communication network wherein the user's private information items are stored as files encrypted via the cipher key.