The article considers the problems of the development of anonymous networks, allowing you to make contacts in the global network invisible to outside observers. All factors affecting the vulnerability of the anonymous network are classified: vulnerabilities that arise at the level of network nodes and at the level of messages sent over the network. It is shown that to ensure anonymity at the level of nodes in the network, it is necessary to hide the topology of the nodes to ensure network survivability and exclude substitution messages. Effectiveness of the strategy of mixing nodes to solve these problems is demonstrated. We analyzed currently known schemes of violating anonymity networks and types of attacks on anonymous networks. We show how anonymity can be violated when intercepting the message at the intermediate node, when identifying the communication template of the network, analyzing the message transmission time. On the basis of the conducted researches we formulated extended requirements for the implementation and development of anonymous networks.