Disclosed is a cannula including a first clamping portion, a second clamping portion and a force applying portion configured to apply at least two different clamping forces across the first clamping portion and the second clamping portion when the cannula is in a closed state. An authentication node generates a secret and transmits the secret to a node providing a service. In one embodiment of the invention, a schema is generated which is utilized to reorder and partition the data into low entropy and high entropy portions which are separately compressed by conventional compression methods. The method further includes obtaining a plurality of surrounding pixels that are positioned within a predetermined area surrounding the target pixel.