Identity theft is a crime and it has always been a problem. Earlier, people disclosed their Social Security numbers (SSN) to anyone who asked for it, without a second thought. Scammers took advantage of that and many were victimized. Due to this problem, the government of the United States established the Identity Theft Task Force in the year 2006. The aim of this task force is to cut down on fraud and on the unnecessary use of these numbers. It requires people to provide their Social Security numbers only to certain authorities.
If you lose your Social Security card, you need to apply for a replacement and you must immediately report the loss of your card to the Social Security Administration. This will help you to prevent fraudsters from illegally using your SSN. Remember that non-US citizens who have permission to work in America, US citizens born within the United States and abroad, and Green Card holders alone can apply for Social Security Cards.
The Privacy Act of 1974 states that you will not be denied government services and benefits if you fail to provide your SSN. You need to provide this number only if you engage in a transaction that requires a notification to the Internal Revenue Service or if you engage in a financial transaction that is subject to the rules of the federal Customer Identification Program. While engaging in such transactions, companies may refuse to do business with you if you fail to provide your SSN.
Apart from that, there are few businesses that require their customers to provide their SSNs for certain legitimate reasons. Insurance companies and credit card companies generally require their customers to provide their Social Security numbers. You need to be very careful about sharing this number as sharing this information to strangers is likely to make you a victim of identity theft. You need to enter your SSN in certain immigration applications and you need to keep your Social Security card safe.