A channel is used to send information from one entity to another.
One property of a channel is its secured status: a secured channel is one which an adversary cannot read or manipulate, whereas an unsecured channel is one which an adversary can read or manipulate.
Another property is physical secureness: a physically secure channel is inaccessible to an adversary, a physically insecure channel, on the other hand, is accessible to an adversary.
L. R. Knudsen, M. J. B. Robshaw, The Block Cipher Companion. Springer, 2011.
Copyright © 2014 Barry Watson. All rights reserved.