Key technological advances in wireless communications, micro electro mechanical systems (MEMS), and digital circuitry have energized the research community to focus on the challenges of wireless sensor networks. In this paper, we propose a new pre-distribution key management scheme that meets the operational and security requirements of wireless sensor networks and provides authentication and key distribution in one set of protocols. Our scheme allows selective key revocation and node rekeying and posits improved network resiliency over existing key pre-distribution schemes. The scheme is based on probability key sharing among sensor nodes of a random graph and incorporates a threshold property. Uncompromised nodes in a sensor network are secure provided that an adversary compromises less than a threshold-number of nodes. We describe the details of our algorithm and briefly compare it with other proposed schemes.