Abstract
Cryptographic key management requires the use of high levels of security when it is applied for generating, exchanging, storing, and re-keying of keys that are used for communication. In these scenarios, group key management is very crucial in controlling key generation, distribution and updates. However, the major problem that arises is the achievement of a scalable re-key technique triggered by membership change. The security of cryptosystems relies immensely on key management processes. In this paper, we have surveyed the key management protocols that are used for multicast encryption and presented the centralized scheme, decentralized scheme, distributed key management scheme, tree based scheme and cluster based scheme.