Provided is a system of encryption key management, which is used by a service provision server which provides a cloud service. The system comprises a key access server which encrypts the service key using a master key corresponding to the service key and provides the service key in response to a service key request from the service provision server and a master key management server which extracts a plurality of key fragments from the master key, processes the extracted key fragments to be stored in a distributed manner, and provides the master key reconstructed from the key fragments in response to a master key request from the key access server.