As the feature of delay tolerant networks (DTNs) is open, and intermittent, any node can participate in this type of network. Trusting a DTN node becomes a critical task for the routing algorithms. For the past few years, security techniques have evolved and a lot of research has been carried out in this area. Among these security techniques, trust-based, reputation-based systems, and incentive-based security schemes are discussed in this paper. These techniques are useful to detect selfish DTN nodes and noncooperative DTN nodes. These schemes for DTN nodes are the most common methods to detect malicious, selfish DTN nodes. © Springer Science+Business Media Singapore 2017.