The National Institute of Open Schooling is the world's largest open-schooling system and the autonomous body of the Ministry of Education that issues secondary, senior-secondary, vocational and DElEd certificates. Pass-out students can verify their certificates online via NIOS's Online Verification service, which returns the printed mark-sheet and pass certificate as a digitally-signed PDF after entering the enrolment number and other details. Universities and employers in India and abroad rely on the same service for third-party authenticity checks. Hard-copy verification by post is also available for a prescribed fee where the digital record is not yet archived.