About Social Security Numbers

A Social Security Number (SSN) is a nine-digit identification number issued by the United States Social Security Administration (SSA). It was originally created in 1936 for tracking earnings and benefits but has become a de facto national identification number used for employment, taxation, credit reporting, and many other purposes. Due to their sensitive nature and widespread use, SSNs are prime targets for identity theft, making their protection critically important.

SSN Format Structure

The standard SSN format is XXX-XX-XXXX, where:

• First Three Digits (Area Number): Originally indicated the state where the SSN was issued
• Middle Two Digits (Group Number): No special meaning, issued in a non-sequential pattern
• Last Four Digits (Serial Number): Assigned sequentially within each group

Historical Area Number Assignment

Before 2011, the first three digits indicated the state where the SSN was issued:

Area Numbers	Region
001-003	New Hampshire
004-007	Maine
040-049	Massachusetts
050-134	New York
135-158	New Jersey
545-573	California
575-576, 750-763	Hawaii

Note: Since June 25, 2011, the SSA implemented SSN Randomization, eliminating the geographic significance of the area number.

Invalid SSN Patterns

Certain SSN patterns are considered invalid and will never be issued:

• 000-XX-XXXX: Area number 000 is never used
• 666-XX-XXXX: Area number 666 is never used
• 9XX-XX-XXXX: Area numbers starting with 9 are not issued (some 900-999 reserved for ITIN)
• XXX-00-XXXX: Group number 00 is never used
• XXX-XX-0000: Serial number 0000 is never used
• 078-05-1120: Used in advertising, known as the "Hogan's SSN"
• 219-09-9999: Used as an example in Social Security publications

SSN Randomization (2011)

In 2011, the SSA implemented SSN Randomization to address:

• Depletion of available SSNs in certain area number groups
• Privacy concerns about geographic information in SSNs
• Identity theft concerns related to predictable SSN patterns
• The need to extend the longevity of the nine-digit SSN system

After randomization, SSNs are issued randomly and no longer have geographic significance.

When SSN Validation is Used

• Employment: I-9 form verification (employers must verify, not validate format)
• Financial Services: Account opening, credit applications
• Healthcare: Insurance and Medicare enrollment
• Government Services: Tax filing, benefits applications
• Education: Student loans, financial aid applications

Important: Format validation should be the first step, followed by verification through official channels (SSA, credit bureaus) when legally required and authorized.

SSN vs ITIN vs EIN

Type	Purpose	Format	Issued By
SSN	Individual taxpayer ID for US citizens/residents	XXX-XX-XXXX	Social Security Administration
ITIN	Individual taxpayer ID for non-residents	9XX-XX-XXXX (starts with 9)	IRS
EIN	Employer/Business identification	XX-XXXXXXX	IRS

Test SSN Patterns

The Social Security Administration has designated certain numbers for testing and examples:

Test Pattern	Purpose
219-09-9999	Official SSA example number
987-65-4320 to 987-65-4329	Reserved for advertising and media

Warning: Even these "test" numbers should only be used in controlled testing environments and never with real systems that connect to credit bureaus or government databases.

Legal and Regulatory Considerations

Identity Theft and SSNs

SSNs are the most valuable piece of information for identity thieves:

• Used to open fraudulent credit accounts
• File false tax returns for fraudulent refunds
• Obtain government benefits illegally
• Secure employment using another person's identity
• Obtain medical services and prescriptions

Best Practices for SSN Handling

• Minimize Collection: Only collect SSNs when legally required
• Truncate Display: Show only last 4 digits (XXX-XX-1234)
• Encrypt Storage: Use strong encryption for SSNs in databases
• Limit Access: Restrict access to authorized personnel only
• Secure Transmission: Use HTTPS/TLS for any SSN transmission
• Audit Logs: Maintain logs of all SSN access
• Regular Training: Train employees on SSN handling procedures
• Incident Response: Have a plan for SSN data breaches
• Alternative IDs: Use alternative identifiers when possible

Red Flags for Fraudulent SSNs

• SSN issued before the person's date of birth
• Multiple people using the same SSN
• Person using multiple SSNs
• SSN with an invalid area number (000, 666, 900-999)
• SSN not yet issued by SSA based on area/group/serial
• Recently deceased person's SSN being used

E-Verify and SSN Verification

Employers can verify SSNs through official channels:

• E-Verify: Department of Homeland Security system for employment eligibility
• SSNVS: Social Security Number Verification Service for employers
• Death Master File: SSA database of deceased individuals

Important: These systems should only be used by authorized entities for legitimate purposes.

Alternatives to SSN

Organizations should consider alternatives to SSN for identification:

• Randomly generated unique IDs
• Username/password combinations
• Email addresses
• Biometric authentication
• Two-factor authentication tokens
• Smart cards or physical tokens

This Tool's Limitations

Reporting SSN Misuse

If you suspect SSN fraud or identity theft:

• Report to SSA: Call 1-800-772-1213 or visit ssa.gov/fraud
• FTC Identity Theft: Report at IdentityTheft.gov
• Credit Freeze: Place fraud alerts with credit bureaus
• Law Enforcement: File a police report
• IRS: Report tax-related identity theft to IRS Identity Protection

Additional Resources

• Social Security Administration: ssa.gov
• Identity Theft Resource Center: idtheftcenter.org
• FTC Identity Theft: identitytheft.gov
• SSA Fraud Reporting: ssa.gov/fraud