This part 9 of the IEC 62351 series specifies cryptographic key management, namely how to generate, distribute, revoke, and handle X.509 digital certificates and cryptographic keys to protect digital data and its communication. Included in the scope is the handling of asymmetric keys (e.g. private keys and X.509 digital certificates), as well as symmetric keys for groups (GDOI). This part assumes that other standards have already chosen the type of keys and cryptography that will be utilized, since the cryptography algorithms and key materials chosen will be typically mandated by an organization s own local security policies and by the need to be compliant with other international standards. This document therefore specifies only the management techniques for these selected key and cryptography infrastructures. The objective is to define requirements and technologies to achieve interoperability of key management. The purpose of this standard is to guarantee interoperability among different vendors by specifying or limiting key management options to be used. This standard assumes that the reader understands cryptography and PKI principles.