Patent ID: 8443190

Claim:
A method for securing a two-way communications channel between at least a network N 1 and a network N 2 with a lower level of security than N 1 , said method comprising at least the following steps: defining one or more types of data authorized to be transmitted from N 1 to N 2 ; for a datum transmitted from N 1 to N 2 : if the datum is of a type authorized to be transmitted between N 1 and N 2 , routing the datum to a first filtering step performed by electronic circuits configured to perform the first filtering step, otherwise routing the datum to an encryption step, if the datum is routed to the first filtering step: saving the context associated with this datum, applying one or more analysis filters to the datum to prevent the creation of a hidden communications channel, for a datum transmitted from N 2 to N 1 : if the datum is of a type authorized to be transmitted between N 1 and N 2 , routing the datum to a second filtering step performed by electronic circuits configured to perform the second filtering step, otherwise routing the datum to a decryption step; if the datum is routed to the second filtering step: comparing the context of the datum with the context saved in the first filtering step and blocking the datum if the contexts are inconsistent, otherwise, applying one or more analysis filters to the datum.