What is DSC?

Also called: Digital Signature Certificate

A DSC is a cryptographic certificate on a USB token that serves as a legally valid electronic signature for filings with the MCA, the income tax portal and the GST portal.

Class 3 is the grade required for company and tax filings. Certificates are issued by licensed certifying authorities for one or two years and must be renewed before expiry.

The token is physical and the private key never leaves it, which is what makes the signature legally equivalent to a handwritten one under the Information Technology Act.

Why it matters

A DSC expiring unnoticed stops every statutory filing that needs a signature — usually discovered on the day of a deadline.

The statutory position

Each figure with the provision it comes from, so it can be checked.
What	Position	Source
Legal effect	A digital signature is legally equivalent to a handwritten one	Section 5, Information Technology Act 2000
Class required for MCA filings	Class 3	MCA e-filing requirements
Validity	One, two or three years depending on the certificate purchased	Certifying Authority terms under the IT Act
Issued by	Certifying Authorities licensed by the Controller of Certifying Authorities	Section 24, Information Technology Act 2000

Not to be confused with

These get used interchangeably, including by tools that should know better. They are different things.

E-signature on the income tax portal

Aadhaar OTP verification on the income tax portal is a different mechanism and is not accepted for MCA filings, which need a Class 3 DSC on a hardware token.

A scanned signature

An image of a signature has no legal standing under the IT Act. A DSC is a cryptographic certificate tied to a token you physically hold.

Questions people ask

What happens when it expires?

Every filing that needs it stops until it is renewed, and renewal is a fresh issuance with verification rather than a click. Expiry dates cluster because certificates are usually bought together at incorporation — worth diarising before a filing deadline finds it.

Can two people share one DSC?

No. A DSC is tied to one individual and signing with someone else's is a misrepresentation. Each director and each authorised signatory needs their own.

What usually goes wrong

Discovering the expiry on the day of an annual filing deadline
Registering the DSC on the MCA portal against the wrong DIN, so filings are rejected
Buying a Class 2 certificate, which is no longer accepted for MCA filings
Losing the hardware token, which means a fresh issuance rather than a recovery