DSN is a special network which can provide a useful interface to the real world with their data acquisition and processing capabilities. However, DSN is extremely vulnerable against any type of internal or external attacks, due to resource constraints, lack of tamper-resistant packages, and the nature of its communication channels. Therefore, it is necessary to develop useful security mechanisms which are suitable for DSN. With the recent acceleration in research into secure key distribution, we compare and contrast different key distribution approaches. We aim to identify the distinguish features and weighing up the benefits and drawbacks of each.