Class 3 digital signature is used for e-tendering or e-procurement by vendors of various companies like Air India, Petroleum Companies & Indian Railways. Class 3 Digital Signature is issued by Certifying Authority which is (n) Code & e-Mudhra. Class-III Digital Signature is used for e-Tendering, e-Procurement, e-Governance, Railway, DGS&D, IFFCO, Air India, ONGC,GAIL,IOC etc.