A resource is protected by an armor structure comprising a magnetic field such that the magnetic field will interfere with a warhead blast to weaken the blast. In particular, magnetic field will interfere with a molten metal jet from a shaped charge to disperse the jet, allowing subsequent layers of armor to absorb the jet energy without penetration. In one embodiment, the magnetic field is produced by a layer of magnetic material magnetized with the field lines perpendicular to the primary threat direction and typically parallel to the surface of the area to be protected. The magnetic material layer may include ferromagnetic (iron or steel, or other) layers to strengthen and contain the magnetic field, protect the magnetic material and act as additional armor layers. The magnetic layer is typically used in conjunction with an inner shield armor layer to absorb the diffused jet after passing through the magnetic layer.