This paper presents PeerCube, a DHT-based system aiming at??minimizing performance penalties caused by high churn while??preventing malicious peers from subverting the system through??collusion. This is achieved by i) applying a clustering??strategy to support quorum-based operations; ii) using a??randomized insertion algorithm to reduce the probability with which??colluding Byzantine peers corrupt clusters, and; iii)??leveraging on the properties of PeerCube's hypercube structure to??allow operations to be successfully handled despite the corruption??of some clusters. In spite of a powerful adversary that can inspect the??whole system and issue malicious join requests as often as it??wishes, PeerCube guarantees robust operations in O(logN) messages, with N the number of peers in the system. Extended??simulations validate PeerCube robustness.