  Establishing secret common randomness between two or multiple devices in a
network resides at the root of communication security. The problem is
traditionally decomposed into a randomness generation stage (randomness purity
is subject to employing often costly true random number generators) and a
key-agreement information exchange stage, which can rely on public-key
infrastructure or on key wrapping. In this paper, we propose KERMAN, an
alternative key establishment algorithm for ad-hoc networks which works by
harvesting randomness directly from the network routing metadata, thus
achieving both pure randomness generation and (implicitly) secret-key
agreement. Our algorithm relies on the route discovery phase of an ad-hoc
network employing the Dynamic Source Routing protocol, is lightweight, and
requires minimal communication overhead.
