Certificate Validation on Windows XP with Entrust SSP Issued HSPD-12 Certificates
On May 9th, 2009 Entrust Managed Services (provider of HSPD-12 certificates) performed a key update ceremony on the Entrust Managed Services Root and SSP certification authorities. HSPD-12 certificates issued after May 9th, 2009 will not work on the Windows XP operating system (i.e. RTM, SP1, SP2 and SP3).
More information can be found here:
http://blogs.technet.com/futurefedtech/default.aspx
