Abstract. In peer-to-peer based live streaming systems, a great number of participants have to cooperate to efficiently and reliably distribute a continuous flow of data. Each receiving peer in return provides its resources to the system. Since these systems operate in a completely distributed manner, it is of particular importance, to prevent malicious members from harvesting important topology information or influencing the streaming system to their needs. In this article, we analyze potential attack methods on multiple-tree-based P2P streaming systems, discuss important design decisions to constrain the impact of malicious behaviour, and we introduce the new concept of peer testaments. By analyzing existing systems, we show that so far only few attention has been given to the design of unexploitable construction mechanisms. Based on the identified design decisions, we propose a novel streaming system and evaluate it by exposing it to different types of internal attackers. Our re...