What Do EID, VID, URN and SRN Mean? Aadhaar (Aadhar) Glossary in Plain English

How do you find a term quickly?

Pick a letter, then the term. Each term below has its plain meaning, where you see it, and a link to the guide that covers it.

How long is each Aadhaar number, and what does it look like?

Most mix-ups happen because the numbers look alike. Count the characters and check whether the number starts with the letter S.

All of the last four work on UIDAI's Check Enrolment / Update Status page. It also accepts the 14-digit enrolment number alone. See update status and rejection fixes.

Which number do I have?

Basics: who runs Aadhaar, and what is the Aadhaar number?

UIDAI (Unique Identification Authority of India)

The government body that issues Aadhaar and runs its websites, app and helpline. Real UIDAI websites end in uidai.gov.in.Where you see it: uidai.gov.in, every Aadhaar letter · Guide: Aadhaar: complete guide

Aadhaar number (UID) (Unique ID)

Your permanent 12-digit Aadhaar number. One person gets one number, and a number is never given to anyone else. It proves identity, not citizenship.Where you see it: front of the card, e-Aadhaar · Guide: Find a lost Aadhaar number or EID

Numbers: what are EID, SID, VID, URN and SRN?

EID (Enrolment ID)

The 28-digit number on the slip you get when you enrol: a 14-digit enrolment number plus a 14-digit date and time stamp. It is not your Aadhaar number. You can use it to check your status and to download e-Aadhaar.Where you see it: enrolment acknowledgement slip · Guide: Enrolment status & not received

SID

An ID made of the letter 'S' and 27 digits. UIDAI uses it for NRC Assam cases, in place of an EID. It works like an EID for checking status and downloading e-Aadhaar.Where you see it: slip from an enrolment or update centre · Guide: Enrolment status & not received

VID (Virtual ID)

A 16-digit number linked to your Aadhaar that you can use in place of the Aadhaar number, for example to download e-Aadhaar. Only you can generate it, and it is free. Only one VID works at a time. It has no expiry, but making a new one cancels the old one; you must wait at least one day between new VIDs. Agencies may not store it. You need a VID before you can lock your Aadhaar.Where you see it: myAadhaar, Aadhaar App, SMS from 1947 · Guide: Lock Aadhaar & biometrics, VID

URN (Update Request Number)

An 8-digit number for tracking an update. UIDAI's status page ties the 8-digit URN to update requests made in the old mAadhaar app. Some guides call the URN a 14-digit number. For an update done at a centre, track it with the number printed on your slip: a 14-digit number there is most likely the enrolment number, which the status page also accepts.Where you see it: mAadhaar update acknowledgement · Guide: Update status & rejection fixes

SRN (Service Request Number)

The letter 'S' followed by 13 digits. You get it with an online request: an address update, an Aadhaar App update, a PVC card order or a Head of Family request. Use it to track that request.Where you see it: online acknowledgement, PVC order, HoF request · Guide: Update status & rejection fixes

Login & checks: what are OTP, e-KYC and authentication?

OTP (One-Time Password)

A 6-digit code sent by SMS to the mobile linked to your Aadhaar. It works only for a short time. Never share it with anyone who calls or messages you. UIDAI says new OTP requests are blocked for 30 minutes after too many tries.Where you see it: download, update, KYC · Guide: OTP, face & biometric authentication

Registered mobile (mobile number linked to Aadhaar)

The mobile number saved in your Aadhaar record. Aadhaar OTPs for download, online updates and locks go to this number. Without it you can't download e-Aadhaar; a centre can add or change it.Where you see it: most online services · Guide: Update mobile number

Captcha

The jumbled letters or numbers you type to prove you are a person, not a computer. UIDAI pages also let you listen to it.Where you see it: UIDAI website forms · Guide: Download e-Aadhaar

e-KYC (Electronic Know Your Customer)

An identity check done with Aadhaar (OTP or biometrics) instead of paper copies, for example at a bank, at a ration shop's ePoS machine or for LPG. Aadhaar is not mandatory for a bank account or SIM card.Where you see it: banks, ration shops, LPG · Guide: Is Aadhaar mandatory?

Authentication (Aadhaar authentication)

Checking that you are you against UIDAI's records, by demographic details, fingerprint, iris, face or OTP. UIDAI sends an email notice for each authentication. If biometrics fail, the agency must offer another way.Where you see it: ration shop, bank, app · Guide: OTP, face & biometric authentication

Face authentication (Face Auth)

Proving your identity with a live face scan by the phone camera, matched against your enrolment photo (Aadhaar App or Face RD app). It needs good light. In our experience the face scan is the most common reason an app mobile update fails (this can vary).Where you see it: Aadhaar App registration and mobile update, UMANG · Guide: The new Aadhaar App

Card types: what is the difference between e-Aadhaar, PVC and masked Aadhaar?

e-Aadhaar (Electronic Aadhaar)

The Aadhaar letter as a PDF file you download yourself, free. It is digitally signed and legally as valid as the paper letter. It opens with a password.Where you see it: myAadhaar, Aadhaar App, DigiLocker · Guide: Download e-Aadhaar

PDF password

The password that opens e-Aadhaar: the first 4 letters of your name in CAPITALS plus your year of birth. Example: SURESH KUMAR born 1990 → SURE1990.Where you see it: opening the e-Aadhaar PDF · Guide: PDF password helper

Masked Aadhaar

An e-Aadhaar that shows only the last 4 digits of the number. You choose it with a tick box while downloading. It is the safer copy to share as ID.Where you see it: option while downloading · Guide: e-Aadhaar vs PVC vs masked

Aadhaar letter

The original paper Aadhaar sent by India Post after your Aadhaar is generated. UIDAI's Citizen's Charter says the letter goes to India Post within 10 days of generation.Where you see it: by post · Guide: Enrolment status & not received

PVC card (Aadhaar PVC card)

A plastic, wallet-size Aadhaar card you order online for ₹75, including GST and Speed Post, on myAadhaar or, in our experience, in the Aadhaar App. It comes to the address on your Aadhaar; UIDAI's page says up to 30 days. Since October 2025 it has no hologram.Where you see it: myAadhaar PVC order page · Guide: Order an Aadhaar PVC card

Baal Aadhaar (child Aadhaar)

Aadhaar for a child below 5. Only a photo is taken, no fingerprints or iris. In most cases it is made through a parent or legal guardian (Head of Family), and the child's address comes from that person's Aadhaar.Where you see it: child enrolment · Guide: Baal Aadhaar for children

Security & proof: what do the signature, QR code and locks mean?

Digitally signed (digital signature)

An electronic seal from UIDAI inside the e-Aadhaar PDF. It shows the file is genuine and unchanged. You can validate it in Adobe Reader.Where you see it: e-Aadhaar PDF · Guide: Download e-Aadhaar

Validity Unknown

A status a PDF reader may show for the signature before you validate it. Validate the signature (see the download guide) to get a green tick. In our experience banks and the passport office ask for an e-Aadhaar with a validated signature.Where you see it: Adobe Reader on e-Aadhaar · Guide: Download e-Aadhaar

Secure QR code

The QR code on Aadhaar. It holds your name, address, gender, date of birth, photo, the last 4 digits of the number and a masked mobile and email. Only the Aadhaar App, UIDAI's QR scanner app or UIDAI's Windows reader can read it, even offline. Scanning it helps you spot a fake card.Where you see it: card, e-Aadhaar · Guide: Verify an Aadhaar

Offline e-KYC (XML) (Paperless Offline e-KYC)

A digitally signed file you download from myAadhaar. It holds your name, address, photo, gender, date of birth, a reference ID and a coded (hashed) form of your mobile and email. You can give it for KYC instead of a photocopy.Where you see it: myAadhaar · Guide: Verify an Aadhaar

Share code

A code used with the Offline e-KYC file. Our sources don't yet confirm the details, so follow the steps on the myAadhaar Offline e-KYC page when you download it.Where you see it: Offline e-KYC download · Guide: Verify an Aadhaar

Authentication history

A list of when your Aadhaar was used for checks over the last 6 months, up to 50 records per view. It shows the type, time, the agency, a transaction ID and the result. Check it to spot misuse.Where you see it: Aadhaar App · Guide: Aadhaar fraud & scams

Biometrics

Your photo, all 10 fingerprints and both iris (eye) scans, stored with your Aadhaar. Children below 5 give only a photo. A biometric update costs ₹125, except the free child updates (see MBU).Where you see it: enrolment, updates · Guide: Photo & biometric update

Biometric lock

Switches off fingerprint, iris and face checks on your Aadhaar so nobody can misuse them. A blocked attempt shows error 330. You can unlock with your registered mobile online, in the Aadhaar App or at a centre. In our experience it is often a safer everyday choice than a full Aadhaar lock.Where you see it: myAadhaar, Aadhaar App, SMS to 1947 · Guide: Lock Aadhaar & biometrics, VID

Aadhaar lock (UID lock)

Locks your Aadhaar completely: biometric, demographic and OTP checks all stop, with the Aadhaar number and with the VID. You need a VID before locking and the latest VID to unlock. The lock is free, has no expiry and stays until you unlock. In our experience unlocking can be hard when UIDAI's site is down, so generate and save your VID first. While it is locked, Aadhaar checks such as bank e-KYC don't work. You need your registered mobile to lock or unlock, and for everyday protection the biometric lock is often the safer choice.Where you see it: UIDAI lock/unlock page, Aadhaar App · Guide: Lock Aadhaar & biometrics, VID

Updates: what are demographic details, MBU and the 10-year update?

Demographic details

Your written details: name, address, date of birth, gender, mobile and email. Changing them costs ₹75, or nothing when done with a biometric update. Email update in the Aadhaar App is free until 31 Dec 2026. Add up your own fee with the fee calculator.Where you see it: update forms · Guide: Aadhaar update: fees & limits

MBU (Mandatory Biometric Update)

The compulsory update of a child's photo, fingerprints and iris at age 5 and again at 15. It is free at 5–7 and 15–17, and free at 7–15 until 30 Sep 2027. If it is not done after age 7, the Aadhaar may be deactivated. Find your child's due date with the child update due-date calculator.Where you see it: children's Aadhaar, SMS reminders · Guide: Child biometric update (5 & 15)

10-year document update

UIDAI says holders may update their identity and address proof at least once every 10 years. It is free on myAadhaar until 14 June 2027, and ₹75 at a centre. In our experience skipping it doesn't deactivate Aadhaar, but some KYC can get stuck.Where you see it: myAadhaar · Guide: 10-year document update

Update history

Secondary sources describe an 'Update History' (beta) service: a list of past updates with the URN, date and type of each, opened with an OTP login.Where you see it: UIDAI's online services (check the current menu) · Guide: Update status & rejection fixes

Deactivated

An Aadhaar that UIDAI has stopped, for example for a duplicate, a missed child biometric update, age fraud or a death record. The fix depends on the reason. A missed child update is done at a centre. A wrong death record or age fraud goes to the Regional Office.Where you see it: Check Aadhaar Status (valid / active) · Guide: Aadhaar deactivated? Reactivate

Documents: what are PoI, PoA, DoB proof, PoR and HoF?

PoI (Proof of Identity)

A document that proves who you are; it must show at least your name and photo. Examples: passport, voter ID, driving licence. PAN is not accepted; it is in none of UIDAI's lists. Check your own papers with the document checker.Where you see it: UIDAI's document list · Guide: Documents required for Aadhaar

PoA (Proof of Address)

A document that shows your current address. Examples: an electricity bill not older than 3 months, or a rent agreement. A bank photo passbook counts as address proof for updates only, not for a new Aadhaar.Where you see it: UIDAI's document list · Guide: Documents required for Aadhaar

DoB proof (Proof of Date of Birth)

A document that proves your date of birth, such as a birth certificate, 10th marksheet or passport. For a child born on or after 1 Oct 2023, only the birth certificate counts.Where you see it: DoB update · Guide: Change date of birth

PoR (Proof of Relationship)

A document showing your relation to the Head of Family. It must show both your name and theirs, for example a birth certificate (for a child) or a marriage certificate.Where you see it: HoF route · Guide: Update your address

HoF (Head of Family)

A family member aged 18+ with an Aadhaar whose details are used for yours. For a child's enrolment the HoF must be the mother, father or legal guardian. For an address update it can also be your spouse, child/ward or sibling. For an online address request, the HoF approves it in their own login within 30 days.Where you see it: address update, child enrolment · Guide: Update your address, Baal Aadhaar

Schedule II

The official list of documents UIDAI accepts, last replaced in May 2026. It has four lists: age 0–5, age 5–18, adults 18+ (enrolment) and updates.Where you see it: UIDAI's document list · Guide: Documents required for Aadhaar

Gazette notification

The government's official publication of a name change. You need it for a complete name change in Aadhaar.Where you see it: name change · Guide: Change your name

Annexure

A fixed-format affidavit or self-declaration that UIDAI's procedures ask for in some cases. Examples: Annexure-II for an operator error in the date of birth, or the annexure affidavits reported for some name corrections. It is not the same as the address certificate in UIDAI's format that an officer signs.Where you see it: DoB and name corrections · Guide: Change date of birth, Change your name

Where to go: which websites, apps and centres handle Aadhaar?

myAadhaar (myaadhaar.uidai.gov.in)

UIDAI's official website for online services: download, address and document update, status, VID and PVC orders. UIDAI is moving services to myaadhaarbeta.uidai.gov.in.Where you see it: browser · Guide: Download e-Aadhaar

Aadhaar App (replaced mAadhaar)

UIDAI's official mobile app, launched in January 2026. It keeps up to 5 profiles, shares details, locks biometrics, shows authentication history and updates mobile, address and email. Data from the old mAadhaar app does not carry over.Where you see it: Play Store / App Store · Guide: The new Aadhaar App

DigiLocker

The government's online document locker. In our experience e-Aadhaar from DigiLocker is accepted at banks and offices. Aadhaar centres, though, want physical original documents, not DigiLocker copies.Where you see it: digilocker.gov.in, app · Guide: Download e-Aadhaar

UMANG (Unified Mobile Application for New-age Governance)

A government app with many services, including e-Aadhaar download. New EPF UANs are activated through UMANG with face authentication.Where you see it: UMANG app · Guide: Link Aadhaar with EPF/UAN

ASK (Aadhaar Seva Kendra)

UIDAI's own Aadhaar centres, open 7 days a week, 9:30 am to 5:30 pm, closed on holidays. Booking an appointment is free, up to 2 a month, and doesn't need your Aadhaar mobile.Where you see it: bookappointment.uidai.gov.in · Guide: Aadhaar centres: what to expect, Book an appointment

Enrolment / update centre

Any authorised place, such as a bank, post office, CSC or government office, where Aadhaar is made or updated. New adult enrolment happens only at designated centres. Find one on the Bhuvan Aadhaar map.Where you see it: Bhuvan Aadhaar portal · Guide: Aadhaar centres: what to expect

Registrar (and enrolment agency)

An organisation UIDAI authorises to run Aadhaar centres, such as a bank or a state department; the agencies and operators work under it. For an update beyond the lifetime limit, registrars must still accept the request. News reports say a registrar can be fined ₹50,000 for proven overcharging.Where you see it: complaints about a centre · Guide: Aadhaar complaint & escalation

CSC / VLE (Common Service Centre / Village Level Entrepreneur)

A government-backed local service centre and the person who runs it. In our experience only a CSC with an authorised Aadhaar centre can do all services. A normal CSC can only order a PVC card, download and print.Where you see it: villages, towns · Guide: For agents & cyber cafés

IPPB (India Post Payments Bank)

The post office bank. IPPB's site lists Aadhaar mobile update at your doorstep for ₹75 at selected post offices only, and free child enrolment (below 5) at a few. In our experience the visit after booking can be late or not happen (this can vary).Where you see it: post office, postman · Guide: Aadhaar services at home (IPPB)

1947 (UIDAI helpline)

UIDAI's free helpline. The automated line runs 24x7; agents answer Mon–Sat 7am–11pm and Sun 8am–5pm, in 12 languages. The same number takes SMS commands from your registered mobile, such as making a VID; build them with the SMS command generator.Where you see it: phone · Guide: UIDAI helpline 1947

Linking: what are PAN linking, seeding, DBT and AePS?

PAN card (Permanent Account Number)

Your income-tax ID. Most PAN holders must link it with Aadhaar (some groups, such as non-residents and people aged 80+, are exempt); your name, date of birth and gender must match in both. PAN is not accepted as a document for Aadhaar itself.Where you see it: PAN-Aadhaar link, bank, ITR · Guide: Link Aadhaar with PAN, Fix name/DOB mismatch · PAN side: link PAN with Aadhaar, PAN vs Aadhaar name checker

Seeding (Aadhaar seeding)

Linking your Aadhaar to a bank account in the national (NPCI) mapper so government payments reach you. "Linked" for bank KYC is not the same as "seeded".Where you see it: bank, myAadhaar Bank Seeding Status · Guide: Bank seeding & DBT not received

NPCI mapper

The national list that decides which one bank account receives Aadhaar-based government payments. You can check or move it on NPCI's BASE portal or through your bank.Where you see it: bank, DBT · Guide: Bank seeding & DBT not received

DBT (Direct Benefit Transfer)

Subsidy or scheme money the government sends straight to the bank account your Aadhaar is mapped to, for example the LPG subsidy.Where you see it: LPG, scheme payments · Guide: Bank seeding & DBT not received

AePS (Aadhaar enabled Payment System)

Taking cash at a micro-ATM or bank agent with just your Aadhaar number and fingerprint; no OTP is involved. Fraudsters misuse copied fingerprints this way, so lock your biometrics and share only masked copies.Where you see it: bank mitra / business correspondent · Guide: Aadhaar fraud & scams

Technical: what are RD devices, AUA and CIDR?

RD device (Registered Device)

A certified fingerprint or iris scanner that centres, banks and ration shops use for Aadhaar checks. If your finger isn't read, retry, try another finger and clean the finger and scanner.Where you see it: centres, ration shops · Guide: Fingerprints not matching

AUA / KUA (Authentication / e-KYC User Agency)

Companies or departments allowed to check identity with Aadhaar. The agency's name appears in your authentication history.Where you see it: authentication history · Guide: OTP, face & biometric authentication

CIDR (Central Identities Data Repository)

UIDAI's central database where Aadhaar records are kept. Unauthorised access to it is punishable under the Aadhaar Act with up to 10 years in jail.Where you see it: background, UIDAI pages · Guide: Is Aadhaar mandatory?

Which mix-ups happen most, and how do you fix them?

Bottom line

Count the characters: 12 is your Aadhaar number, 16 a VID and 28 an EID. Numbers starting with 'S', or with 8 digits, only track requests. Keep your OTP to yourself. For anything unclear, UIDAI's free helpline is 1947.