UIDAI Verify: How UIDAI Verification Works & How to Fix Signature Issues

What Is UIDAI?

UIDAI stands for the Unique Identification Authority of India. It's a statutory authority established in January 2009 under the Government of India. Its only job — and it does it at an astonishing scale — is to issue and manage Aadhaar, India's biometric-linked 12-digit unique identity number.

As of 2024, UIDAI has enrolled over 1.38 billion residents. That makes Aadhaar the world's largest biometric ID system, bar none. The central database UIDAI maintains is called the CIDR (Central Identities Data Repository). It stores your demographic data (name, address, date of birth, gender) alongside your biometrics (fingerprints, iris scans, and face photograph). Every time someone authenticates using Aadhaar, the request is verified against this CIDR in real time.

UIDAI operates under the Ministry of Electronics and Information Technology (MeitY) and is governed by the Aadhaar (Targeted Delivery of Financial and Other Subsidies, Benefits and Services) Act, 2016. The authority also regulates the Aadhaar ecosystem — licensing Authentication User Agencies (AUAs) and KYC User Agencies (KUAs) who are authorised to use Aadhaar for identity verification.

Its official website is uidai.gov.in. The resident-facing services portal is myaadhaar.uidai.gov.in.

What Is UIDAI Verification?

"UIDAI verification" actually refers to two distinct things that people often mix up:

1. Number Verification — confirming that a given 12-digit Aadhaar number actually exists in the UIDAI database and is currently active.
2. Identity Authentication — confirming that the person presenting the Aadhaar number is genuinely who the number belongs to, using OTP, biometrics, demographics, or a combination.

A third — and often overlooked — meaning is document verification, specifically validating the digital signature on an e-Aadhaar PDF to confirm it was genuinely issued by UIDAI and hasn't been altered.

Let's walk through each of these in detail.

How to Verify an Aadhaar Number on the UIDAI Portal (Step-by-Step)

This is the most basic form of UIDAI verification. It confirms that a particular Aadhaar number is real and active. It does not reveal personal data — only an age band, gender, state, and the last three digits of the registered mobile number are shown.

Step 1 — Go to the Official Portal

Open myaadhaar.uidai.gov.in in your browser. Do not use unofficial third-party websites — they are not authorised to access UIDAI's database.

Step 2 — Navigate to "Verify an Aadhaar Number"

Under the Aadhaar Services section on the myAadhaar homepage, click "Verify an Aadhaar Number". This service is available without logging in — it's a public check.

Step 3 — Enter the 12-Digit Aadhaar Number

Type the 12-digit Aadhaar number you want to verify. Double-check it — a single transposed digit will either return "invalid" or accidentally verify someone else's number.

Step 4 — Enter the CAPTCHA

Enter the on-screen CAPTCHA code exactly as shown. This prevents automated mass lookups.

Step 5 — Click "Proceed"

The system queries the CIDR and returns a result within seconds. A valid, active Aadhaar will display:

• Age band (e.g., 25–29 years)
• Gender
• State of residence
• Last three digits of the registered mobile number (if any)

If the number is invalid, cancelled, or doesn't exist, you'll get a clear error message.

What This Verification Does NOT Tell You

This check tells you whether the number is active. It does not tell you whether the person standing in front of you actually owns that Aadhaar. For that, you need full authentication (OTP or biometric), covered below.

How to Verify Your Registered Mobile Number or Email

Want to know if your mobile number or email ID is actually linked to your Aadhaar? UIDAI provides a separate check for this at myaadhaar.uidai.gov.in.

1. Go to myaadhaar.uidai.gov.in and log in with your Aadhaar number and OTP.
2. Under Aadhaar Services, click "Verify Email/Mobile Number".
3. Enter the mobile number (or email) you want to verify.
4. Click Send OTP — an OTP will be sent to that number only if it is registered.
5. Enter the OTP to confirm linkage.

This is incredibly useful before applying for schemes or services that send OTPs to your Aadhaar-linked mobile. If you've changed phones and never updated UIDAI, the OTPs will silently fail and you'll be locked out.

UIDAI Authentication Types Explained

When UIDAI talks about "authentication," it means proving that a living person is who they claim to be using one or more factors. There are four main types:

Every authentication results in a simple Yes/No response from UIDAI's CIDR — the requesting agency never gets your full biometric or personal data. That's by design.

UIDAI OTP Verification — Deep Dive

OTP-based Aadhaar verification is the method most people encounter on a daily basis. It's how you log in to the income tax portal, how your bank verifies your KYC update, how DigiLocker links to your Aadhaar. It's everywhere.

How the OTP Actually Gets to You

When you initiate an OTP-based transaction, the requesting entity (bank, government portal, etc.) sends your Aadhaar number to UIDAI's authentication API. UIDAI looks up your registered mobile/email and dispatches a time-bound, one-use 6-digit OTP. The OTP is valid for typically 10–30 minutes depending on the use case.

What if You Don't Have a Registered Mobile?

OTP authentication will simply fail. You cannot receive the OTP on an unregistered number. In this situation, you need to visit an Aadhaar Seva Kendra (ASK) to update your mobile number first, or switch to biometric authentication if the service provider supports it.

The TOTP Option (mAadhaar App)

UIDAI also supports a Time-based OTP (TOTP) generated locally on the mAadhaar app. This means you can authenticate even without a live network signal, as long as your phone has the mAadhaar app installed and configured. The TOTP refreshes every 30 seconds.

Security: Notifications After Every Authentication

Every time an OTP authentication is processed on your Aadhaar number, UIDAI sends a notification to your registered mobile and email. If you receive one you didn't initiate, immediately contact UIDAI at 1947 or email help@uidai.gov.in.

UIDAI Biometric Verification — Deep Dive

Biometric authentication is the most secure form of UIDAI verification because it can't be transferred. Your fingerprint, iris, or face is something you physically are — unlike a password or OTP, it can't be phished or forwarded.

How Fingerprint Authentication Works

A STQC-certified fingerprint scanner captures a Fingerprint Minutiae Record (FMR). This is not a photograph — it's a mathematical representation of ridge patterns. The FMR is encrypted and sent to UIDAI. UIDAI compares it against the 10-fingerprint template stored in CIDR. A match returns "Yes."

Why Fingerprints Sometimes Fail (And What To Do)

Manual labourers, the elderly, and people who work with chemicals often have worn or degraded fingerprints. UIDAI has recognised this and issued guidelines requiring service providers to have exception-handling mechanisms. In practice this means: if fingerprint fails, try iris. If that fails too, opt for OTP or face authentication. Nobody should be denied a service purely because of fingerprint quality.

How Iris Authentication Works

Iris scanners capture a high-resolution image of the iris (the coloured ring around your pupil). The pattern of the iris is unique to each eye and remains stable over a lifetime. UIDAI's CIDR stores iris templates captured during enrolment. Iris authentication is often deployed where fingerprints are unreliable.

Face Authentication — The Newest Mode

Face authentication is increasingly used for remote, mobile-first verification. UIDAI's RD (Registered Device) framework ensures the face capture happens on a certified device. The live image is matched against the photograph stored in CIDR. It's contactless and works on any standard smartphone camera.

Locking and Unlocking Your Biometrics

UIDAI lets you lock your biometrics via the mAadhaar app or the myAadhaar portal. When locked, nobody — not even a certified AUA — can authenticate using your fingerprint or iris. You can unlock it at any time. This is a powerful fraud-prevention tool, especially if you've received suspicious authentication alerts.

How UIDAI Digitally Signs Your e-Aadhaar PDF

When you download your e-Aadhaar from the myAadhaar portal, you receive a password-protected PDF. That PDF is not just a scan — it's a digitally signed document in the PDF/A format. Understanding how that signature was created is key to understanding why it might show "Validity Unknown" on your screen.

The Signing Chain

UIDAI signs every e-Aadhaar using a PKI (Public Key Infrastructure) chain. Here's how it works in plain English:

1. UIDAI's Certificate Authority (CA) — UIDAI uses a certified Certifying Authority, such as (n)Code Solutions CA or eMudhra, which is accredited under India's Controller of Certifying Authorities (CCA). These CAs issue the digital certificates UIDAI uses for signing.
2. UIDAI's Signing Certificate — UIDAI holds a private key that only it possesses. When you download your e-Aadhaar, UIDAI uses this private key to create a unique digital signature that is mathematically tied to the exact content of your PDF. Change a single pixel and the signature breaks.
3. The Certificate Embedded in the PDF — Along with the signature, UIDAI embeds its public certificate inside the PDF. When you open the PDF in a reader, it extracts this certificate to verify the signature.

The signature ensures two things: authenticity (the document came from UIDAI) and integrity (the document hasn't been modified since signing). Learn more about this process in our detailed guide on UIDAI e-Aadhaar digital signature validation and getting the green tick.

What the Signature Looks Like in the PDF

When you open your e-Aadhaar, look at the bottom of the last page. You'll see a box — usually containing text like "Digitally signed by DS UIDAI 2017" or a similar signer name followed by date and time. That box is the signature field. The icon next to it tells you the signature status.

The UIDAI Root Certificate Explained

Here's where most people get confused — and where most guides fall short.

Your PDF reader (Adobe Acrobat, Foxit, even browser PDF viewers) maintains a trust store — a list of root certificate authorities it inherently trusts. Adobe's trust store is called Adobe Approved Trust List (AATL) and is updated periodically via the cloud.

The problem is that India's CCA (Controller of Certifying Authorities) root certificate, under which UIDAI's signing certificates are chained, is not included in the Adobe AATL by default for most users. Adobe updates its trust list over time, but older installations or offline systems may not have the Indian CCA root.

This is the fundamental reason why your e-Aadhaar shows a yellow question mark instead of a green tick. Your PDF reader is saying: "I see a signature and it looks mathematically correct, but I don't recognise the authority that issued this certificate — so I can't tell you for sure if it's trustworthy."

Where UIDAI's Certificate Chain Sits

The full chain looks like this:

CCA India Root (Root CA)
  └─ (n)Code Solutions CA 2014 / eMudhra CA (Intermediate CA)
       └─ DS UIDAI XXXX (UIDAI Signing Certificate)
            └─ Your e-Aadhaar signature

For your PDF reader to show a green tick automatically, it needs to recognise the CCA India Root as a trusted root. Once it does, it can validate the entire chain up to your document signature.

For a complete walkthrough of how to add the UIDAI certificate to your trust store manually (and why that's often not enough), see our guide on how to validate the digital signature in your e-Aadhaar online.

The "Validity Unknown" Problem — What It Is and Why It Happens

You've downloaded your e-Aadhaar, you've opened it in Adobe Acrobat Reader, and you see a yellow question mark with the text "Validity Unknown." You're not alone — this frustrates millions of people every single year.

Let's be clear about something: a "Validity Unknown" status does NOT mean your Aadhaar is fake or invalid. It means your PDF reader cannot locate and verify the signing certificate chain within its current trust store. The document itself is almost certainly genuine.

Three Root Causes of "Validity Unknown"

1. The CCA India Root Certificate Is Not in Your Trust Store

As explained above, if your Adobe Acrobat or PDF viewer hasn't received the Indian CCA root via AATL, it won't recognise UIDAI's signing certificate. This is the most common cause.

2. Your Adobe Acrobat Is Outdated or Offline

Adobe updates its AATL via an online sync. If your software is outdated or your PC hasn't connected to the internet since installation, the root list may be stale and missing the CCA India certificate even if Adobe has added it.

3. The PDF Lacks LTV (Long Term Validation) Information

This is the most technically nuanced cause — and the one that catches even technically savvy users by surprise.

LTV stands for Long Term Validation. When a PDF signature is created, it ideally embeds three things: the signing certificate, a timestamp from a trusted Time Stamping Authority (TSA), and Online Certificate Status Protocol (OCSP) or CRL data that proves the certificate was valid at the time of signing.

Without LTV data embedded in the PDF, a validator has to go online and fetch certificate revocation data in real time. If it can't reach those servers — or if the certificate has since expired — the signature shows as "Validity Unknown" or even fails outright. UIDAI's e-Aadhaar PDFs are signed correctly, but standard viewers often fail to fetch the necessary revocation data dynamically, especially in offline scenarios or when the original OCSP/CRL endpoint is unreachable.

This is the exact problem that our guide on fixing the Aadhaar card signature "Validity Unknown" problem addresses in detail.

Getting a Permanent Green Tick on Your e-Aadhaar

There are two approaches: the manual route (tedious, often incomplete) and the smart route.

The Manual Route — Adding UIDAI's Certificate to Adobe Trust Store

This involves:

1. Opening the PDF in Adobe Acrobat Reader.
2. Right-clicking the signature field and selecting "Validate Signature."
3. Clicking "Signature Properties" → "Show Signer's Certificate."
4. Going to the "Trust" tab → "Add to Trusted Identities."
5. Checking "Use this certificate as a trusted root."
6. Closing and reopening the PDF.

This works for that specific certificate on that specific machine. If UIDAI ever rotates its signing certificate (and they do, periodically), you'll have to repeat the whole process. It also doesn't embed LTV data into the PDF, so the signature status may still flicker depending on network conditions.

The Smart Route — Embedding LTV Directly with AadhaarVerify.com

If you downloaded your e-Aadhaar PDF and see a Validity Unknown yellow question mark over the digital signature, standard PDF viewers cannot fix this. You must use AadhaarVerify.com to instantly embed LTV (Long Term Validation) and get a permanent Green Tick directly from your browser.

Here's why this approach is fundamentally different:

• LTV Embedding — AadhaarVerify.com fetches all required revocation data (OCSP responses, CRL data, the full certificate chain) and permanently embeds it inside your PDF. The signature becomes self-contained — no external server lookups needed, ever.
• Permanent Fix — Once LTV is embedded, the green tick will show across all compliant PDF viewers, on any machine, even offline, even years from now.
• Browser-Based — No software to install. Upload your PDF, process, download. Done in under 60 seconds.
• Privacy-Safe — Your Aadhaar data stays on your device. The processing happens client-side.

Want to understand the technical difference between a regular validated signature and an LTV-embedded one? Read our deep dive on Aadhaar digital signature validation online.

When Would You Actually Need a Green Tick?

Most people don't worry about this until it bites them. Common scenarios where a verified green-tick e-Aadhaar is required:

• Submitting Aadhaar as proof of identity in legal or notarial processes
• Uploading to government portals that electronically verify the document signature (EPFO, NPS, passport office)
• Property registration or loan applications where the bank insists on a digitally verified Aadhaar
• Sending your Aadhaar via email to a third party who wants to confirm it hasn't been photoshopped
• Educational institutions verifying original documents online

For a complete explainer on why digital signature validation matters (and whether it's legally mandatory on a printed Aadhaar), see our article on whether a digital signature is mandatory for a printed Aadhaar card.

Checking Your Aadhaar Authentication History

UIDAI maintains a log of every authentication request made using your Aadhaar number. This is called Aadhaar Authentication History and it's available to you free of charge.

How to Check

1. Go to myaadhaar.uidai.gov.in and log in.
2. Click "Aadhaar Authentication History" under Aadhaar Services.
3. Select a date range and authentication type (OTP, biometric, demographic, or all).
4. Click "Send OTP" — an OTP is sent to your registered mobile for security.
5. Enter the OTP. The history will display with timestamps and agency names.

What to Do If You See Suspicious Activity

If you notice an authentication you didn't initiate:

• Immediately lock your biometrics via mAadhaar or myAadhaar.
• Call UIDAI helpline at 1947.
• File a complaint at your nearest police station citing Aadhaar misuse.

The history is retained for a limited period, so check it periodically rather than only when something goes wrong.

Biometric Lock & Unlock — A Critical Security Feature

UIDAI's biometric lock is one of the most underused security features in the Aadhaar ecosystem. It lets you freeze your biometric data so that no entity, anywhere, at any time can authenticate a biometric request against your Aadhaar — until you unlock it.

How to Lock Your Biometrics

• Via mAadhaar app: Open the app → tap "Biometric Settings" → tap "Enable Biometric Lock."
• Via myAadhaar portal: Log in → go to "Aadhaar Services" → click "Lock/Unlock Biometrics" → verify with OTP → lock.

Temporary Unlock

When you need to do a biometric authentication (e.g., at a bank or ration shop), you can temporarily unlock your biometrics. The unlock lasts for a specified window (typically the next authentication or a few minutes), after which it auto-locks again. This gives you surgical control over when your biometrics can be used.

Who Should Lock Their Biometrics?

Everyone. Especially:

• People who have received suspicious authentication alerts.
• Elderly persons who rarely need biometric authentication.
• Residents living in areas with known Aadhaar fraud activity.

UIDAI Paperless Offline e-KYC

Offline e-KYC is UIDAI's solution for scenarios where you want to share your identity details without going through a live online authentication. Instead of the service provider connecting to UIDAI's servers in real time, you share a digitally signed XML file containing your Aadhaar data.

How It Works

1. Log in to myaadhaar.uidai.gov.in and navigate to "Offline e-KYC."
2. Set a share code (a 4-digit PIN of your choice) — this encrypts the XML file.
3. Download the signed XML file (it contains your masked Aadhaar number, name, gender, DoB, address, and photo — encrypted).
4. Share the XML file and the share code with the service provider.
5. The service provider decrypts and verifies the digital signature on the XML to confirm it came from UIDAI.

Why This Is Better Than Photocopying Your Aadhaar

A photocopy can be forged. A UIDAI-signed XML cannot — at least not without breaking the cryptographic signature. The offline e-KYC XML also uses a masked Aadhaar number (only last 4 digits visible), protecting your full number from unnecessary exposure.

Service providers can verify the digital signature on the offline e-KYC XML using the same UIDAI certificate chain described above. If they encounter a validation issue, the same LTV embedding approach applies.

Common UIDAI Verification Errors and How to Fix Them

Frequently Asked Questions About UIDAI Verification