2.2.1.1.2.8 X-MS-PolicyKey
The X-MS-PolicyKey header contains the client's current policy key, as specified in [MS-ASPROV] section 2.2.2.42. This header SHOULD NOT be used if the base64-encoded query value is being used. Instead, the Policy key field of the base64-encoded query value SHOULD be set, as specified in section 2.2.1.1.1.1.