The security of wireless sensor networks is an active topic of research where both symmetric and asymmetric key cryptography issues have been studied. Due to their computational feasibility on typical sensor nodes, symmetric key algorithms that use the same key to encrypt and decrypt messages have been intensively studied and perfectly deployed in such environment. Because of the wireless sensor's limited infrastructure, the bottleneck challenge for deploying these algorithms is the key distribution. For the same reason of resources restriction, key distribution mechanisms which are used in traditional wireless networks are not efficient for sensor networks.