There are 3 names in this directory beginning with the letter D.
According to section 8.1, chapter 8 of foreign trade policy 2015-2020, these are transactions that are treated as exports even though the goods aren’t leaving the country yet. You may be supplying goods to Export Oriented Units, software or hardware technology parks, or government-funded projects, and getting paid in either INR or free foreign exchange (equivalent of INR in the currency of the customer for the invoice date).
DSC or Digital Signature Certificate is an electronic document or key which is digitally encrypted document. It is issued by a certifying authority and contains the personal details and credentials of an individual or a designated signatory of a company. Under GST, while filing returns this key is used to validate and establish the credentials of a taxpayer.