In state-of-the-art Delay Tolerant Network (DTN) routing algorithms, two encountering nodes rely on routing utilities (e.g., probabilities of meeting other nodes) to decide the better carrier (defined forwarder) for their packets. As the utilities and forwarder information reflect user privacy, nodes may be reluctant to disclose such information, which however is indispensable in routing. To handle this challenge, we propose two distributed strategies to protect the aforementioned private information in utility-based DTN routing algorithms while still guarantying the correctness of packet forwarding, namely meeting Relationship Anonymity (ReHider) and Forwarder Anonymity (FwHider). ReHider anonymizes routing utilities between two encountered nodes, while FwHider additionally hides the forwarder information among the group of encountered nodes on top of the routing utility anonymity. We also present enhanced versions of the two strategies that can better prevent certain malicious behaviors such as probing attack and brute-force attack. The proposed strategies are distributed without the need of a central authority for authentication or key management. They can be applied to any utility-based DTN routing algorithms. Extensive analysis, trace-driven simulation, and smartphone based test demonstrate the effectiveness and energy efficiency of the proposed strategies.