Next to authentication, secure key exchange is considered the most critical and complex issue regarding ad-hoc network security. We present a low-cost, (i.e. low hardware-complexity) solution for feasible frequent symmetric key exchange in adhoc networks, based on a Tree Parity Machine Rekeying Architecture. A key exchange can be performed within a few milliseconds, given practical wireless communication channels and their limited bandwidths. A flexible rekeying functionality enables the full exploitation of the achievable key exchange rates. Characteristics of a standardcell ASIC design realisation as IP-core in -technology are evaluated. $\textcent \sterling $\? {\S} \copyright