The concept of Aadhaar is a statutory scheme established by the Aadhaar (Targeted Delivery of Financial and Other Subsidies, Benefits and Services) Act, 2016. It is a 12-digit unique identity number issued to every resident of India. The project was initiated in 2009 to create a single, unique identification system, solving the problem of inefficiency and duplication caused by reliance on multiple identity documents for public service delivery. The Act provides legal backing for the scheme, which aims for efficient and transparent delivery of subsidies and services funded from the Consolidated Fund of India.
The scheme is managed by the Unique Identification Authority of India (UIDAI), a statutory authority established under Section 11 of the Act. The mechanism involves collecting demographic data and biometric data, which includes a photograph, ten fingerprints, and two iris scans. The 12-digit number is generated after a de-duplication process, with the last digit being a checksum calculated using the Verhoeff algorithm. Section 7 of the Act allows the government to mandate Aadhaar for beneficiaries to access certain subsidies and services. For authentication, the system returns only a "yes-or-no" confirmation of identity, and the Act strictly prohibits the sharing of core biometric data.
A key legal connection is the Supreme Court's 2018 judgment in Justice K.S. Puttaswamy and Anr. v. Union of India, which read down Section 57 of the Act, restricting the mandatory use of Aadhaar by private entities. The Aadhaar and Other Laws (Amendment) Act, 2019, subsequently allowed the voluntary use of Aadhaar for services like opening bank accounts and obtaining mobile connections. Recently, the Aadhaar Authentication for Good Governance (Social Welfare, Innovation, Knowledge) Amendment Rules, 2025, notified in February 2025, expanded the use of Aadhaar authentication to non-government entities in sectors like e-commerce and healthcare. Furthermore, the Aadhaar (Enrolment and Update) First Amendment Regulations, 2025, issued on July 2, 2025, codified the UIDAI's authority to cancel duplicate Aadhaar numbers, retaining the earliest one with biometric information.