TL;DR
- Personally Identifiable Information (PII) refers to any data that can identify an individual, such as names, email addresses, social security numbers, or IP addresses.
- PII is vital to protect because it is highly sensitive and commonly targeted in cyberattacks, identity theft, and data breaches.
- Organizations must understand and safeguard PII to maintain customer trust and comply with regulations like GDPR, CCPA, and HIPAA.
- PII includes direct and indirect identifiers—and businesses are legally and ethically responsible for protecting both.
Introduction
Personally identifiable information (PII) is any data that can be used to identify a specific individual. It may consist of a single identifier, like a Social Security number, or a combination of data points such as a birthdate and full name.
PII is a cornerstone of data privacy and cybersecurity because it enables direct or indirect identification of people. Organizations must understand what constitutes PII in order to protect it, comply with global regulations, and avoid reputational or financial harm.
What Counts as PII?
PII includes various types of personal, legal, biometric, and digital information. Rather than list dozens of items all at once, here’s a categorized overview:
Identity and Contact Information
- Full name
- Email addresses (work or personal)
- Phone numbers
- Home or mailing address
- Mother’s maiden name
- Marital status
Government and Legal Identifiers
- Social Security number
- Driver’s license number
- Passport number
- Alien registration number
- Security clearance information
Sensitive Personal Attributes
- Date of birth
- Gender, race, ethnicity
- Religious or political affiliation
- Medical data and records
- Employment information
- Criminal history
Financial and Account Information
- Bank account or credit card numbers
- Account usernames and passwords
- Last 4 digits of an SSN
Digital and Biometric Data
- IP addresses and cookie IDs
- Geolocation data
- Log-in credentials
- Biometric identifiers (e.g., fingerprints, retinal scans, voice signatures)
- Social media photographs
Types of PII by Region
The definition of PII varies slightly depending on jurisdiction. Here’s how it’s categorized in the United States and the European Union:
United States – Sensitive PII
In the U.S., personally identifiable information is often further classified based on potential harm. This subset is referred to as Sensitive PII.
“Sensitive PII is personally identifiable information, which if lost, compromised, or disclosed without authorization, could result in substantial harm, embarrassment, inconvenience, or unfairness to an individual.” — U.S. Department of Homeland Security (DHS)
Examples of Standalone Sensitive PII (source: Department of Homeland Security)
- Social Security numbers
- Driver’s license or state ID numbers
- Passport numbers
- Alien registration numbers
- Bank or financial account numbers
- Biometric data (e.g., fingerprints)
Examples of In Combination Sensitive PII (source: Department of Homeland Security)
- Citizenship or immigration status
- Personal contact info combined with name
- Medical details with identifying info
- Religious or ethnic affiliation
- Criminal history
- Date of birth + other identifiers
European Union – Personal Data under GDPR
The General Data Protection Regulation (GDPR) offers a broader definition:
“Any information relating to an identified or identifiable natural person (data subject).”
GDPR also specifies a special category of Sensitive Personal Data, which includes personal attributes that could be misused for discrimination or profiling.
Examples of Personal Data (source: GDPR)
- Name and surname
- Email address or phone number
- Home address or location data
- Date of birth
- IP address or cookie ID
- Hospital or doctor-held data
- National ID or credit card number
Special Category (Sensitive) Data (source: GDPR)
- Racial or ethnic origin
- Political opinions
- Religious or philosophical beliefs
- Trade union membership
- Genetic or biometric data
- Cultural or social identity
How Stolen PII is Used
PII is stolen by cybercriminals primarily for monetization purposes — either through identity fraud or by selling it on dark web marketplaces.
- Credit card info: Sells for $50 to $1,000
- Passport details: Fetch hundreds to thousands of dollars
- SSNs or driver’s licenses: Go for a few dollars each but are widely used for fraud
How do businesses protect personally identifiable information (PII)?
Organizations must take proactive steps to safeguard PII across their digital systems. Best practices include:
Regular Client-Side Scanning
Continuously scan client-side applications for hidden threats, JavaScript-based vulnerabilities, and behavioral anomalies.
These scans help uncover security blind spots that traditional server-side protections may miss, such as malicious scripts injected via third-party tools or compromised CDNs.
Access Control & Encryption
Ensure PII is only accessible by authorized personnel and encrypted both in transit and at rest.
Implementing role-based access controls (RBAC) and zero-trust architecture reduces the risk of insider threats and data leakage from over-permissioned users.
Real-Time Monitoring
Deploy detection systems to flag unusual access patterns or potential data exfiltration.
Anomaly detection engines and behavioral analytics can alert security teams to suspicious user behavior before a breach escalates.
Employee Training
Educate teams on secure data handling, phishing risks, and privacy policy compliance.
Regular training sessions combined with phishing simulations foster a security-first culture and help prevent human error—the leading cause of data breaches.
FAQ
What qualifies as PII?
PII includes any data that can directly or indirectly identify a person. This ranges from names and emails to biometric records and device identifiers like IP addresses.
What’s the difference between sensitive and non-sensitive PII?
Sensitive PII (e.g., SSNs, financial data) can cause harm if exposed and requires stronger protections. Non-sensitive PII (e.g., zip codes, gender) may not be damaging alone but can become risky when combined with other data.
Why is protecting PII important?
PII is a prime target for cybercriminals. Failure to protect it can lead to identity theft, financial loss, reputational damage, and heavy regulatory penalties.
Are IP addresses considered PII?
Yes, under many regulations like GDPR, IP addresses are treated as PII because they can often be traced back to an individual.
What laws regulate PII?
Key regulations include:
- GDPR (EU)
- CCPA/CPRA (California)
- HIPAA (U.S. healthcare)
Each has specific rules about how PII must be collected, stored, and shared.
