Smartphones are important communication devices with various network interfaces. These interfaces offer the ability to connect to a mobile ad-hoc network. When establishing an ad-hoc network, the question arises, which adjacent node in such a network can be trusted to deliver the data. The SKIMS project follows a socio-inspired approach in establishing a trust relationship: To find a trustworthy peer for relaying, SKIMS exchanges, compares, and evaluates contact information, which is available at smartphones. It does neither require dedicated infrastructure components, nor pre-shared secrets. A challenge in this approach is the private-set intersection problem. SKIMS uses a commutative encryption scheme to protect the privacy of each smartphone and its owner. This only reveals mutual contacts and thus mitigates privacy concerns. The result of the contact list exchange then allows each smartphone to quantify the reliability of the other peer by accumulating the rating for each entry in the data intersection. This thesis provides a thorough design and implementation of two protocols to privacy-friendly exchange contact data. The performance of both protocols is evaluated in terms of execution speed, CPU-cycles, and network traffic on resource limited smartphones. The implementation is written in Java for the AndroidTM operating system.