When to Give Out Your Social Security Number, How to Protect It

A compromised Social Security number can create a financial headache. Here’s how to keep yours safe.

Lumping Social Security, Medicare and Medicaid together as social entitlement programs is not accurate.

[Read: Protect Yourself From 10 Menacing Financial Scams.]

Don't over-share online. Until 2011, the Social Security Administration assigned Social Security numbers in a predictable way. "If you share your birthday, age and place of birth, for example, on Facebook, studies have shown that Social Security numbers can be predicted based on publicly available information," Messing says. "The Social Security Administration started randomly assigning Social Security numbers in June 2011 for that reason." He recommends never publicly sharing your year of birth and choosing a different year when asked for online forms. "Add or subtract some years, as long as it's a number you'll remember," he says.

Keep your Social Security card in a safe place. Some older people are accustomed to carrying their Social Security cards in their wallets. But if the wallet is lost or stolen, that can create problems. Keep your card in a safe deposit box or another secure location instead. Medicare and Medicaid still print Social Security numbers on cards because of a legacy system, so if you have Medicare or Medicaid, Kelly suggests photocopying the card and blocking all but the last four digits. "Hopefully that's good enough so you're not really carrying it around," he says.

Corrected on 7/2/2013: A previous version of this story failed to note Robert Ellis Smith's full name and title. Both were inadvertently removed during the editing process.