Large-scale wireless sensor networks (WSNs) are highly vulnerable to attacks because they consist of numerous resource-constrained devices and communicate via wireless links. These vulnerabilities are exacerbated when WSNs have to operate unattended in a hostile environment, such as battlefields. In such an environment, an adversary poses a physical threat to all the sensor nodes, that is, an adversary may capture any node compromising critical security data including keys used for confidentiality and authentication. Consequently, it is necessary to provide security services to these networks to ensure their survival. We propose a novel self-organizing key management scheme for large-scale, and long-lived WSNs, called Survivable and Efficient Clustered Keying (SECK) that provides administrative services that ensures the survivability of the network. SECK is suitable for managing keys in a hierarchical WSN consisting of low-end sensor nodes clustered around more capable gateway node...