Aadhaar e-Sign for Contracts: How It Works

What Aadhaar eSign is Aadhaar eSign is an online electronic signature service that lets an Aadhaar holder sign a document digitally after being authenticated against their Aadhaar number, using a one-time password (OTP) sent to their registered mobile, or biometrics. There is no need for a physical cryptographic token or a pre-issued smart card. A short-lived digital signature certificate is created at the moment of signing and applied to the document. It is built on India's digital identity system and the Controller of Certifying Authorities (CCA) framework, and it is one of the two common ways to apply a legally recognised electronic signature in India, the other being a conventional digital signature certificate (DSC) held on a token. ## The legal basis Aadhaar eSign sits within the Information Technology Act, 2000. The Act recognises electronic signatures where the technique is reliable and specified in the Second Schedule, and the eSign online electronic signature service is one such technique. Because each eSign produces a digital signature certificate issued by a licensed certifying authority, it carries the same legal standing as a certificate based digital signature. As with any electronic signature in India, it cannot be used for the document types excluded under the First Schedule of the Act, such as negotiable instruments other than cheques, powers of attorney, trusts and wills, so confirm your document is eligible. ## How the signing flow works The parties in an Aadhaar eSign transaction are: the signer, an Application Service Provider (ASP), which is the platform presenting the document, an eSign Service Provider (ESP), which is a licensed certifying authority or its partner, and the UIDAI, which authenticates the Aadhaar holder. A typical signing runs like this: 1. Open the document. The signer opens the document on the ASP platform and chooses to sign using Aadhaar eSign.

2. Hash the document. The platform creates a unique mathematical fingerprint (a hash) of the document. Only this hash, not the full document, is sent onward for signing, which protects the content.
3. Enter Aadhaar and authenticate. The signer is taken to the ESP, enters their Aadhaar number (or a virtual ID) and chooses OTP or biometric authentication. UIDAI sends an OTP to the registered mobile, or verifies the biometric.
4. UIDAI verifies. UIDAI confirms the identity and returns the authentication result to the ESP. The data UIDAI shares is limited to what is needed to confirm identity.
5. Certificate and signature issued. On success, the ESP, as or on behalf of a licensed certifying authority, generates a short-lived digital signature certificate and signs the document hash. The signer's private key is created in a secure module and destroyed after this single use.
6. Signed document returned. The signed document, with the certificate embedded, is returned to the ASP and to the signer. Anyone can later verify the signature and confirm the document has not changed since. The whole flow takes seconds, which is why Aadhaar eSign is widely used for onboarding, loan documents, account opening and high-volume agreements. ## OTP vs biometric Aadhaar eSign supports two authentication modes: - OTP based. A one-time password is sent to the mobile number registered with Aadhaar. Fast and convenient, suitable for most remote signing, and dependent on the signer having access to that registered mobile.

• Biometric based. The signer authenticates with a fingerprint or iris scan on a compliant device. Used where stronger in-person verification is needed, such as some regulated onboarding. Both produce a valid electronic signature. The choice is about the assurance level and the setting. ## Where Aadhaar eSign fits for contracts Aadhaar eSign is well suited to: - High-volume, standardised agreements where signers are individuals with Aadhaar, such as consumer and lending documents.
• Remote onboarding and account opening.
• Situations where you want a certificate backed signature without issuing physical tokens. It is less suitable where: - A signer does not have Aadhaar, or is outside India, since it depends on the Aadhaar system.
• The document type is excluded from electronic execution under the IT Act.
• A counterparty requires a specific organisational DSC, for example certain statutory or tender filings where a particular certificate class is mandated. For company signatories and many business-to-business contracts, an organisational DSC on a token is often used instead, while Aadhaar eSign shines for individual signers at scale. ## Privacy and security points worth knowing - Only the document hash, not the full document, is sent for signing, so the ESP does not see your contract content.
• The signing private key is generated in a hardware security module and destroyed after a single use, so it cannot be reused.
• Authentication relies on UIDAI, and the signer must have an Aadhaar-registered mobile for OTP signing.
• The resulting signature is verifiable and tamper-evident, like any certificate based digital signature. ## A quick checklist before you use it - Confirm the signer has Aadhaar and, for OTP, access to the registered mobile.
• Confirm the document type is eligible for electronic execution under the IT Act.
• Make sure stamp duty is handled separately where the document requires it; eSign does not pay duty.
• Use a reputable ASP connected to a licensed ESP or certifying authority.
• Keep the signed document and its certificate for verification and record. ## Signing, stamping and tracking in one place Aadhaar eSign handles one step, the signature. A contract still needs drafting, review, stamping where duty applies, and tracking of what it commits you to. Running each of these in a separate tool is how a document gets signed before it is stamped, or signed with the wrong method for its type. A single workspace keeps the steps connected: draft and review the contract, apply stamp duty where needed, send for electronic signing, and track the executed document afterwards, tuned to how your company contracts and to Indian requirements. Adira is built on that single-workspace idea, with e-signing and e-stamping embedded next to drafting and review so the signature method stays matched to the document. The principle is simple whatever you use: authenticate the signer properly, sign a document that is eligible, handle the duty, and keep a verifiable record. This is general information current as of 2026, not legal advice. Confirm current eSign rules, eligible document types and provider details with the CCA, UIDAI or a qualified professional.