Aadhaar

Validator, formatter, and masker for Aadhaar numbers issued by UIDAI.

Aadhaar is the 12-digit unique identity number issued by the Unique Identification Authority of India (UIDAI) to every Indian resident. It is required for:

• Opening bank accounts (RBI KYC mandate)

• Filing income tax returns

• SIM card activation (TRAI mandate)

• Government welfare benefit disbursement (DBT)

• eKYC onboarding at regulated financial institutions

Format: 12 digits, first digit must be 2–9 (UIDAI never issues numbers starting with 0 or 1).

Checksum: Verhoeff algorithm (dihedral group D5). Implementation in io.github.kotindia.internal.Verhoeff — cross-referenced against Wikipedia D5 spec and mastermunj/format-utils JS implementation before finalising lookup tables.

Aadhaar is Private government-level PII protected under the Aadhaar Act 2016, IT Act 2000, and India's DPDP Act 2023. Always mask before logging or displaying. See mask for PII-safe display options.

Accepted input forms (all normalised before validation):

• Raw: "234567890121"

• UIDAI spaced: "2345 6789 0121" — spaces stripped before validation

• Partial spacing: "2345 67890121" — stripped

• Whitespace-padded: " 234567890121 " — trimmed + stripped

This object is stateless and thread-safe.

Samples

Aadhaar.validate("234567890124") // ValidationResult.Valid
Aadhaar.format("234567890124") // "2345 6789 0124"
Aadhaar.mask("234567890124") // "XXXXXXXX0124"