[1] The Time Stamping [2] Policy Server used in conjunction with the Digi-CA™ [3]:
And in so doing makes Digi-CA™ compliant with this standard.
Links:[1] https://www.digi-sign.com/downloads/download.php?id=digi-ca-pdf [2] http://www2.digi-sign.com/digi-ca/time+stamp [3] http://www2.digi-sign.com/digi-ca