Active shield with electrically configurable interconnections

An integrated circuit comprising an active shield said active shield comprising upper layer conductive lines (2) arranged in a shielding manner to cover at least a, part of a security critical circuit (3) arranged in lower layers of an integrated circuit (1);

• electrically controllable switching circuits arranged to select the connections of ones of said upper layer conductive lines (2) to other ones of said upper layer conductive lines (2) to form a multiplicity of data bit lines;
• internal data buses (12) arranged in lower lavers of the integrated circuit (1);
• at least one transmitter (7) and a multiplicity of receivers (8), wherein the transmitter (7) is arranged to transmit test data to the receivers (8) via both the said data bit lines and said internal data buses (12). the said at least one transmitter (7) comprises means for generating a. select signal (11) and means for transmitting the select signal (11) to the said receivers (8) and the said electrically controllable switching circuits (5) via a. data path arranged in lower lavers of the integrated circuit (1), and the said at least one transmitter (7) is arranged to change the value of the said select signal (11) in regular or random time intervals;
• the said electrically controllable switching circuits are arranged to select different ones of said upper layer conductive lines (2) for the different values of the said select signal (11) to change the interconnection configuration (9,10) of the said bit lines;
• the said receivers (8) comprises means for reordering the said bit lines according to the said interconnection configuration (9,10) selected by the said select signal (11) and, the said receivers (8) are configured to compare the test data received from the said bit lines with the actual test data received from the said internal data buses (12), in order to verify the integrity of the said upper layer conductive lines (2).