Section 4(7) in The Digital Signature (End entity) Rules, 2015
(7)To create long term valid digital signature,-(a)a time stamp shall be applied initially to the signed data including the certificates and revocation information;(b)ensure that initial time stamp shall cover all the data and signature(s);(c)a nested time stamp option shall be used to ensure signature validity past the time stamping service provider's (tssp) key or algorithm expiry where the nesting of time stamps implies that a subsequent time stamp shall be applied to the prior time stamp;(d)signature(s) and time stamps may be embedded in the data itself or stored separately as standalone.
