Field of Science

Inferring Social Security Numbers from Birth Data

An article in July's PNAS investigates the possibility of predicting a person's Social Security number from their birth date and place. Exploiting patterns in how SSN's are assigned, authors Alessandro Acquisti and Ralph Gross developed an algorithm which could correctly predict the first 5 digits of a social security number 44% of the time, for people born after 1988 (older SSNs are significantly harder to predict). The accuracy varied from state to state; for smaller states and recent birthdays, the algorithm could sometimes predict an entire SSN on the first try.

Think you're safe?


  1. The first time I was in the Army, one of my fellow recruits in basic was Filipino. If you gave her the first three digits of your SSN, she could tell you where it was issued...the State, anyway. (Even the more populous ones, like California and New York - she had all the 3-digit prefixes memorized.)

    She told me that many of her friends in the Philippines played a bar game using Troops' SSN. (Guess where they were from, and get a free drink - like our boys over there would need an excuse to try and get a woman drunk.)


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