[1] Digi-CAST™ [2] is the system used to implement all Certificate Authority systems. Digi-CAST3™ is the methodology used to implement the compliance strategy for ISO 27001 [3].
Links:[1] https://www.digi-sign.com/downloads/download.php?id=cio-digi-cast-pdf [2] http://www2.digi-sign.com/service/digi-cast [3] http://www2.digi-sign.com/compliance/iso/27001