What Types of Information Should You Protect to Prevent Identity Theft?

Most people picture identity theft as someone stealing their Social Security number. That’s the biggest piece, but it’s far from the only one. Thieves don’t need your SSN if they can piece together enough smaller details to answer your bank’s security questions, reset your passwords, or pass as you over the phone.

Security researchers split personal information into two tiers: direct identifiers, which point straight at you on their own, and quasi-identifiers, which seem harmless individually but become dangerous once combined. Your date of birth alone means nothing — millions of people share a birthday. Your ZIP code alone means nothing either. But your date of birth, ZIP code, and gender together can narrow you down to one specific person out of an entire country. That’s the mechanism most people miss, and it’s why “harmless” data still deserves protecting.

Here’s what falls into each category, and how to actually protect it.

Your Social Security Number — The One That Unlocks Everything Else

This is the master key, and it’s treated differently from everything else on this list for one reason: it doesn’t expire, and in almost every case, it can’t be replaced. A stolen credit card gets canceled and reissued in days. A compromised SSN is a liability for the rest of your life, because it stays the same number forever.

What it unlocks: new credit accounts, tax refund fraud, fraudulent unemployment claims, medical services billed in your name, and employment under your identity.

How to protect it: never carry the physical card, shred anything that prints the full number, freeze your credit before anything happens, and know the warning signs that someone else is already using it — because most victims find out from the fallout, not a notification.

Financial Account Numbers and Payment Card Details

Bank account and routing numbers, credit and debit card numbers, PINs, and online banking credentials. This category moves the fastest once compromised — a stolen card number can be used within minutes of a data breach, sometimes before you even get the notification email.

Protect it by turning on real-time transaction alerts, avoiding saved card numbers on shopping sites you don’t use often, and knowing your liability differs sharply by account type — credit cards cap your loss at $50 (often $0 in practice), but debit card fraud gets far more expensive the longer you wait to report it.

Date of Birth

On its own, mostly harmless. Combined with your name and address, it’s one of the three pieces almost every financial institution and government agency uses to verify identity — which means it’s also one of the three pieces a thief needs to impersonate you convincingly.

Be selective about where you enter a full birthdate. Plenty of loyalty programs and social media platforms ask for it and have no real need for the exact year — a lot of sites accept just the month and day for something like a birthday discount.

Driver’s License and Passport Numbers

Government-issued ID numbers get used to open accounts, pass identity checks a thief couldn’t otherwise pass, or in the more serious cases, create a fraudulent physical ID with your information on someone else’s photo.

If either is lost or stolen, replace it and flag it immediately — a driver’s license number can sometimes be flagged by your state’s DMV so a duplicate license under your name gets caught, and a stolen passport gets reported to the State Department at 1-877-487-2778.

Login Credentials and Security Question Answers

Usernames, passwords, and — this is the one people underestimate — the answers to security questions. “What’s your mother’s maiden name,” “what street did you grow up on,” “what was your first pet’s name.” These questions exist because the answers used to be genuinely hard to find. They aren’t anymore. A few minutes on social media, an old obituary, or a public records search can answer most of them.

Treat security question answers with the same caution as a password. Where a site allows it, give a fabricated answer you’ll remember rather than the true one — the question only needs to match what you entered, not what’s factually accurate about your life.

Medical and Health Insurance Information

Health insurance ID numbers and Medicare numbers can be used to receive medical treatment, get prescriptions filled, or bill procedures in your name. Beyond the financial cost, this category carries a risk most people don’t think about: a thief’s medical history can get merged into your record, which can affect your own future treatment if a doctor makes a decision based on someone else’s blood type, allergies, or diagnosis.

Review the “explanation of benefits” statements your insurer sends after every claim — a service you never received is one of the clearest signs medical identity theft has already happened.

Login Access to Email

Email tends to get overlooked because it doesn’t feel like “financial” information, but it’s often the master key behind every other account. Most password reset links go through email. Someone who controls your inbox can reset your banking password, your credit card login, and your social media accounts one after another, using your own email’s “forgot password” link to do it.

Protect this one hardest of all — a strong, unique password and two-factor authentication on your email account specifically, even if you’re lax about it elsewhere.

Biometric Data

Fingerprints, facial recognition scans, and voice signatures used for phone unlocking or banking apps. Unlike a password, these can’t be changed if they’re ever compromised in a breach — your face and fingerprints are the ones you were born with. This category is newer and less commonly targeted today, but it’s worth being aware of which apps store biometric data versus which only use it locally on your device without transmitting it anywhere.

Combined “Harmless” Details

This is the category almost no one thinks to protect, because none of it looks dangerous by itself:

• Full name plus current or former address
• Employer name and job title
• Names of family members, especially a spouse or children
• Phone number
• Schools attended

Individually, none of this opens an account. Together, it’s often enough to pass a call center’s identity verification, answer a “security” question, or build a convincing phishing message that references real details about your life to seem legitimate. This is also exactly the kind of information data brokers and people-search sites compile and sell without ever needing to breach anything — it’s often just publicly available and aggregated in one place.

Information Belonging to Children and Aging Relatives

A child’s SSN is especially valuable to a thief because it has no credit history attached — nothing to flag as unusual for years. Checking whether a child’s SSN is already being misused is worth doing the moment you’re notified of any breach that involved their information, even if nothing seems wrong yet.

Older relatives carry a different risk: they’re more likely to be targeted directly through phone and mail scams that ask for information outright, rather than information being stolen through a breach. The same categories above apply to them — SSN, financial accounts, medical insurance numbers — but the protection often has to be more hands-on, since the tactic used against them relies on trust rather than theft.

A Quick Way to Decide What Deserves the Most Protection

Ask one question about any piece of information: could this, combined with two or three other public details about me, open an account or pass as verification? If yes, treat it like you’d treat a password — don’t hand it out casually, don’t post it, and don’t assume a request for it is legitimate just because it sounds official.

Frequently Asked Questions

Is my email address actually dangerous if someone gets it?

 On its own, not especially. But if it’s the email tied to your bank, credit cards, or password resets, it becomes one of the highest-value targets on this entire list — control of the inbox often means control of everything connected to it.

Should I be worried about my date of birth being on social media?

 Yes, more than most people realize. It’s one of the standard three pieces of information used to verify identity almost everywhere, so posting your exact birthdate publicly removes one layer of protection you didn’t know you had.

What’s the single riskiest piece of information to have stolen?

 Your Social Security number, because it’s permanent and unlocks the widest range of fraud — credit, tax, employment, and benefits, all under one number that can’t be replaced in most cases.

Do security question answers really matter that much? 

Yes. They’re designed to be secrets only you’d know, but most traditional questions have answers that are publicly discoverable. Treat them like passwords, not trivia.

Is it safe to give out my driver’s license number for things like age verification?

 Only when the request is legitimate and necessary — a bar checking your age, a rental car company. Be more cautious with businesses that have no clear reason to keep the number on file afterward.

Sources

• National Institute of Standards and Technology — SP 800-122, Guide to Protecting the Confidentiality of Personally Identifiable Information
• NIST Computer Security Resource Center — Personally Identifiable Information (PII) Glossary
• Federal Trade Commission — Identity Theft, Consumer Advice
• U.S. Department of State — Reporting a Lost or Stolen Passport

This article is for informational purposes only and does not constitute legal advice. Laws vary by state and individual circumstances differ. For advice about your specific situation, consult a qualified attorney.

Researched and written by Israr Ahmad, legal content researcher and founder of AllAboutLawyer.com.