Digital TV decoder/chip card secure communication/authorization having two couple keys generated each module and symmetrical verification carried out encrypting /de encrypting/ re encrypting module exchange.

摘要

The secure communication method has a first (25) and second module (26) for information exchange. Each module has one of the keys of two couples (30,32;31,33). First (S) and second (A1) random numbers are generated in the first module, a third number (A2) is randomly generated in the second module. Symmetrical verification is carried out to show whether a random number encrypted by one module and de encrypted by the other and re encrypted and transmitted back to the first module for de encryption are identical.