Abstract: Methods and systems disclosed provide for creating private networks for secured communication between devices. The devices can communicate with each other over a secure tunnel created for a closed circle of devices. Furthermore, the methods and systems can enable offline communication between devices on a private network.

Abstract: A magnetic stripe card provides a quantitative tool for the measurement of magnetic sensitivity for fine-grained iron, iron oxide or other ferro-magnetic powders, that may be used for magnetic particle inspection and other purposes. The magnetic stripe card is encoded to establish distinct areas on the magnetic stripe. Each distinct area has a specific magnetic gradient. Ferro-magnetic powders are attracted to the gradient in proportion to the value of the gradient. A higher gradient more strongly attracts the powder. A determination of the sensitivity of the powder can be ascertained by observing the gradient with the lowest value to which the powder is attracted.