Abstract: A method of detecting whether a packet from a plurality of packets transmitted by at least one transmitting station over a network has been played back is disclosed. Each packet includes a message and an identifier, the packets being successively transmitted over several consecutive time periods. The method includes receiving the packet by at least one receiving station and reading of the identifier of the received packet to obtain a received identifier, and consulting, by the receiving station, a database of identifiers already received to determine whether the received identifier has already been received. If the received identifier has not already been received, the method also includes updating the database to include the received identifier. The identifier includes an indicator of belonging to groups of packets.

Abstract: A method is provided for defining a filtering module between a first module processing information with a first sensitivity level, and a second module processing information with a second sensitivity level connected, in parallel with the filtering module, by a cryptographic module. The method includes defining a set of filtering rules in a language that can be compiled, defining the properties of messages whereof transmission is allowed between the first and second modules; validation processing the predefined set of rules, validating that a transmission authorization or refusal has in fact been provided by applying the set of rules to any information that may be provided at the input of the filtering module; compiling the predefined set of rules; and integrating the compiled set of rules into a rules database of the filtering module.

Abstract: A method for the secure exchange of data over an ad-hoc network implementing an Xcast broadcasting service and an associated node are disclosed. The method includes providing a security graph for the network and a communication graph for the network, routing a data item between the sender node sending the data and each receiver node receiving the data along a secure route on the security graph. The method also includes generating, between one relay node and a subsequent relay node of the secure route, an appropriate message, containing the data protected in accordance with a security association shared between the relay node and the subsequent relay node. The method further includes routing the message from the relay node to the subsequent relay node along a communication route on the communication graph.

Abstract: The described technology relates to cryptographic equipment which includes an input interface, a red module, a cryptographic module, a black module, and an output interface. The cryptographic module includes a cryptographic unit, which interacts with the red module and with the black module, and a management device, which interacts with the input interface and with either the red module or the black module, but not with both simultaneously. The cryptographic unit and the management device are physically and logically separate from one another and independent, and have an identical protection mechanism capable of protecting the integrity of the management device so as to detect any attempt at tampering.

Abstract: A method of detecting whether a packet from a plurality of packets transmitted by at least one transmitting station over a network has been played back is disclosed. Each packet includes a message and an identifier, the packets being successively transmitted over several consecutive time periods. The method includes receiving the packet by at least one receiving station and reading of the identifier of the received packet to obtain a received identifier, and consulting, by the receiving station, a database of identifiers already received to determine whether the received identifier has already been received. If the received identifier has not already been received, the method also includes updating the database to include the received identifier. The identifier includes an indicator of belonging to groups of packets.

Abstract: A method for the secure exchange of data over an ad-hoc network implementing an Xcast broadcasting service and an associated node are disclosed. The method includes providing a security graph for the network and a communication graph for the network, routing a data item between the sender node sending the data and each receiver node receiving the data along a secure route on the security graph. The method also includes generating, between one relay node and a subsequent relay node of the secure route, an appropriate message, containing the data protected in accordance with a security association shared between the relay node and the subsequent relay node. The method further includes routing the message from the relay node to the subsequent relay node along a communication route on the communication graph.

Abstract: A method is provided for defining a filtering module between a first module processing information with a first sensitivity level, and a second module processing information with a second sensitivity level connected, in parallel with the filtering module, by a cryptographic module. The method includes defining a set of filtering rules in a language that can be compiled, defining the properties of messages whereof transmission is allowed between the first and second modules; validation processing the predefined set of rules, validating that a transmission authorization or refusal has in fact been provided by applying the set of rules to any information that may be provided at the input of the filtering module; compiling the predefined set of rules; and integrating the compiled set of rules into a rules database of the filtering module.

Abstract: The invention relates to cryptographic equipment which comprises an input interface, a red module, a cryptographic module, a black module, and an output interface. The cryptographic module includes a cryptographic unit, which interacts with the red module and with the black module, and a management device, which interacts with the input interface and with either the red module or the black module, but not with both simultaneously. The cryptographic unit and the management device are physically and logically separate from one another and independent, and have identical protection means capable of protecting the integrity of the management device so as to detect any attempt at tampering.