Creating a Master key in SharePoint 2013

Does anyone know of any restrictions on the passphrase used to create a master key ?

I am getting failures (Invalid data) when I try to create a master key when installing and configuring Sharepoint 2013.  (I am using AutoSPInstaller version 3.93)

The operating system being used is Windows 2012 updated to the November 2013 patch Tuesday and Sharepoint is 2013 with the April 2013 PU and the October 2013 CU.

Or could it be a missing GPO causing the issue ?

Or could it be a SQL 2012 permissions issue ?

Thanks

Nigel

Nigel Price NJPEnterprises