Section 10 in The Digital Signature (End entity) Rules, 2015
10. Verification of xml digital signature.
(1)The verification of the xml digital signature shall be accomplished by signature validation, reference validation and certificate validation and an xml digital signature shall be treated valid only if signature validation, reference validation and certificate validation as specified below are complied with.(2)To accomplish signature validation-(a)canonical form of signed info as produced during reference validation shall be used;(b)canonical form of signature method using the canonicalization method shall be obtained;(c)the public key contained in the signatory's x509 certificate that is included in the xml digital signature, the canonicalisied form of signed info signature value, and canonicalisied form of signature method shall be used to verify the signature.(3)To accomplish reference validation-(a)canonicalise the signed info element based on the canonicalisation method in the signed info shall be used;(b)for each reference in the signed info-(i)if transformations were applied by the signatory, then the verifier software may de-reference the uniform resource identifier (uri) and execute transforms provided by the signatory in the reference element;(ii)compute digest of referenced item using the digest method specified in its reference element;(iii)compare the computed digest value against digest value in the signed info reference; if there is any mismatch or validation fails;(4)The Digital Signature Certificate included in the xml digital signature shall be verified in accordance with the provisions specified in rule 6.(5)To verify counter signature, the signature on electronic record first and signature on previous signature shall be verified serially.(6)To verify parallel signature, signature on electronic record shall be verified independently.(7)To verify long term signature, the initial time stamp and all subsequent time stamp applied on the each prior time stamp shall be verified.
