What is private data?
Definition
Private data is information about you that you haven't chosen to make public and that could be used to identify you or harm you if others got it, such as your home address, ID numbers, health details or account logins.
- Category
- Data
- Also called
- private information, private personal data
- Last updated
"Private data" isn't a single legal term. Laws and standards use their own words: personal information, personally identifiable information (PII), sensitive data. In everyday use it means the details about you that you expect to stay between you and the people or companies you chose to share them with.
The closest official anchor is NIST's definition of PII: information that can be used to distinguish or trace an individual's identity, either alone or when combined with other information that is linked or linkable to a specific person. NIST's examples include a name, a social security number and biometric records, plus date and place of birth and mother's maiden name when combined with other details.
Alone or in combination
A single detail often looks harmless. Your first name isn't private. Your first name, your street and your date of birth together are enough to open an account in your name or find you at home. That's why data brokers matter: they join scattered records into one profile.
A concrete example
You fill in a prize draw form with your name, phone number and postcode. The organiser sells the list. A broker links it to your past addresses and your relatives' names, and now a stranger can look you up for free. None of the pieces was secret on its own.
Private data vs. public data
Some of your details are public by design, such as property or court records, depending on where you live. Private data is what you haven't published. The line blurs once someone collects public pieces into a profile, which is why "it was already public" doesn't mean it's harmless.
Why it matters
The more private data about you is findable, the cheaper it is to impersonate, scam or harass you. You can't control every record, but you can control what you hand out and which listings stay up.
How to protect yourself
- 1
Share the minimum
Leave optional fields blank on forms and sign-ups. Use a separate email address for shops and newsletters.
- 2
Lock down your accounts
Use a unique password for each account and turn on two-step verification, so a leaked password alone can't open your email or bank.
- 3
Tighten social media privacy settings
Remove your birthday, phone number, address and workplace from public profiles, and set accounts to private where you can.
- 4
Find and remove listings that join your details together
Search your name and check people-search sites for your address and phone number, then use each site's opt-out. Serus finds where your address and phone number are listed and removes them for you, and files again when they reappear.
See where your personal data is exposed
Serus finds it on data brokers and people-search sites and removes it.
Frequently asked
What counts as private data?
Anything that identifies you and that you haven't chosen to publish: ID and account numbers, home address, phone number, health and financial details, biometric records, and combinations of smaller details such as date of birth plus postcode.
Is private data the same as PII?
They overlap heavily. PII is the term US standards bodies such as NIST use for information that can identify a person. Private data is the plainer everyday phrase and also covers things you simply want kept to yourself.
Can private data become public without a breach?
Yes. Forms you fill in, public records and data sold between companies can all end up in a profile on a people-search site without anyone hacking anything.
Sources
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