DSC or Digital Signature Certificate which is stored in USB Driver is used to establish one’s identity by signing documents electronically while filing documents online through the internet. It is the digital equivalent to a normal hand written signature.  It also acts as a method of confirming the authenticity of a document online such as Income Tax E-Filing, Annual Return Filing, Company or LLP Incorporation, etc., There are 3 different types of Digital Signature Certificates, Class I, Class II, Class III. Class I type of Digital Signatures are only used for securing email communication. Class II Digital Signature Certificate is usually used for filing Income Tax documents, Registrar of companies and Value Added Tax documents. Class 3 Digital Signature Certificate is mainly used for participation in e-auction & e-tendering.