Why do I have to provide my SSN, date of birth, and set new challenge questions to lock my SSN in E-Verify?

To protect your privacy and make the system as secure as possible, myE‑Verify does not store a plain text version of your Social Security number (SSN) or date of birth, but these items are necessary to create the lock. Additionally, you must select challenge questions in case you have to unlock your SSN over the phone.