Starting with vSphere plugin 5.3.1, authenticating with Pure1 through the plugin's managed keys is far simpler than user managed keys. If the environment doesn't require user managed keys, using plugin managed keys is recommended.
From the vCenter web UI, left-click the (1) hamburger, left-click (2) Everpure then left-click (3) AUTHENTICATE WITH PURE1.
Select the (1) Plugin managed keys bullet, select and copy the entire (2) Public Key and leave this screen open. This public key will be used in Pure1 to generate the Application ID for use a little later.
Log in to the Pure1 web GUI at pure1.purestorage.com. From there, left-click (1) API Registration then left-click (2) + Register Application.
Populate a (1) Name for the application, paste the (2) Public Key from earlier and finally select a (3) Pure1 Role. Specify either the admin role or read only. Please note the Public Key must start with -----BEGIN PUBLIC KEY----- and end with -----END PUBLIC KEY-----
Select and copy the (1) Application ID to paste into the vCenter web GUI in the next step.
Switch back to the vCenter web GUI page and paste the (1) Application ID from the previous step and left-click (2) AUTHENTICATE.