Digital signature
Authentication of an electronic record by a subscriber by means of an electronic method or procedure in accordance with Section 3 of the Information Technology Act, 2000.
Explained
Section 2(1)(p) of the Information Technology Act, 2000 defines digital signature as authentication of any electronic record by a subscriber by means of an electronic method or procedure in accordance with the provisions of Section 3. Section 3 fixes the technology: authentication is effected by an asymmetric crypto system and hash function which envelop and transform the initial electronic record into another electronic record. Any person holding the subscriber's public key can verify the record, and the private key and the public key are unique to the subscriber and form a functioning key pair. The hash function must make it computationally infeasible to reconstruct the original record from the hash result or to produce the same hash result from two records.
Since the 2008 amendment the Act uses the wider, technology neutral concept of electronic signature. Section 2(1)(ta) defines it as authentication by an electronic technique specified in the Second Schedule, and it includes a digital signature. Section 3A lays down when an electronic signature is reliable: the signature creation data must be linked to the signatory and under his control alone, and any alteration of the signature or of the information after signing must be detectable. So every digital signature is an electronic signature, but not every electronic signature is a digital signature.
Section 5 gives legal recognition: where a law requires a signature, the requirement is satisfied by an electronic signature affixed as prescribed. Certifying Authorities issue certificates under Section 35, and a Digital Signature Certificate is defined in Section 2(1)(q). The Act does not apply to the documents listed in the First Schedule (Section 1(4)).
In evidence, Section 73 of the BSA lets the Court, to verify whether a digital signature is that of the person said to have affixed it, direct that person, the Controller or the Certifying Authority to produce the Digital Signature Certificate, or direct any other person to apply the public key in the certificate and verify the signature. Section 66 of the BSA requires proof of an electronic signature, other than a secure electronic signature. Examiners test Section 3, the relationship with electronic signature, and Section 73 of the BSA.
What the law says
(p) “digital signature” means authentication of any electronic record by a subscriber by means of an electronic method or procedure in accordance with the provisions of section 3;
Section 2(1)(p) digital signature; 2(1)(ta) electronic signature
(1) Subject to the provisions of this section any subscriber may authenticate an electronic record by affixing his digital signature.
(2) The authentication of the electronic record shall be effected by the use of asymmetric crypto system and hash function which envelop and transform the initial electronic record into another electronic record.
Explanation.–For the purposes of this sub-section, “hash function” means an algorithm mapping or translation of one sequence of bits into another, generally smaller, set known as “hash result” such that an electronic record yields the same hash result every time the algorithm is executed with the same electronic record as its input making it computationally infeasible–
Authentication by asymmetric crypto system and hash function
[(1) Notwithstanding anything contained in section 3, but subject to the provisions of sub-section (2), a subscriber may authenticate any electronic record by such electronic signature or electronic authentication technique which–
(a) is considered reliable; and
(b) may be specified in the Second Schedule.
Reliable electronic signatures
Where any law provides that information or any other matter shall be authenticated by affixing the signature or any document shall be signed or bear the signature of any person, then, notwithstanding anything contained in such law, such requirement shall be deemed to have been satisfied, if such information or matter is authenticated by means of [electronic signature] affixed in such manner as may be prescribed by the Central Government.
Explanation.–For the purposes of this section, “signed”, with its grammatical variations and cognate expressions, shall, with reference to a person, mean affixing of his hand written signature or any mark on any document and the expression “signature” shall be construed accordingly.
Legal recognition of electronic signatures
In order to ascertain whether a digital signature is that of the person by whom it purports to have been affixed, the Court may direct—
(a) that person or the Controller or the Certifying Authority to produce the Digital Signature Certificate;
(b) any other person to apply the public key listed in the Digital Signature Certificate and verify the digital signature purported to have been affixed by that person.
Proof and verification of digital signatures in Court
Earlier law: IEA 73A. Proof as to verification of digital signature.
Except in the case of a secure electronic signature, if the electronic signature of any subscriber is alleged to have been affixed to an electronic record, the fact that such electronic signature is the electronic signature of the subscriber must be proved.
Proof of electronic signature
Earlier law: IEA 67A. Proof as to electronic signature.
For the exam
- Section 2(1)(p) IT Act; method fixed by Section 3 (asymmetric crypto system and hash function).
- Private key signs; public key verifies; the two form a unique key pair.
- Electronic signature (Section 2(1)(ta), 3A) is wider and includes digital signature.
- Section 5 IT Act gives legal recognition to electronic signatures.
- Section 73 BSA: Court may direct production of the certificate or verification by public key.
70 questions in the Law Maker question bank use this term. Practise Cyber Law questions
Related terms
- Electronic signatureAuthentication of an electronic record by a subscriber using an electronic technique specified in the Second Schedule to the IT Act, including a digital signature (Section 2(1)(ta)).
- Electronic recordData, a record or data generated, an image or sound stored, received or sent in electronic form, or micro film or computer generated micro fiche (Section 2(1)(t) of the IT Act).
- Computer resourceComputer, computer system, computer network, data, computer data base or software (Section 2(1)(k) of the Information Technology Act, 2000). It is the widest of the Act's technology terms.
- IntermediaryA person who, on behalf of another, receives, stores or transmits an electronic record or provides a service for it, such as an internet provider, search engine or online marketplace. Section 2(1)(w) IT Act.
- DocumentAny matter expressed, described or recorded on any substance by letters, figures, marks or other means, intended or usable to record or prove that matter, and including electronic and digital records.
Further reading
Checked 6 November 2026. Statutory text is quoted from the Bare Acts library, taken from India Code. See the full glossary.