When the protocol is first initialized, the AD FS server must have access to its Artifact Store ADM element, where it stores state about OAuth authorization codes issued by it for the duration of the artifact lifetime. The AD FS server stores an artifact, whose format is defined in section 220.127.116.11. The artifact identifier is used to look up and retrieve the artifact from the artifact store. Therefore, the AD FS server MUST ensure that the artifact identifier is unique across its Artifact Store ADM element. Access to the Artifact Store ADM element must be initialized before the AD FS server services requests by using the ADFSOAL Protocol.