I get asked this many, many times during the week, and instead of repeating myself, here is the answer to your questions about CPN/SCN being illegal or legal.
Credit Profile Numbers or Secondary Credit Numbers are legal, however if you step over that line, they can become illegal very quickly.
1. A CPN or SCN is NOT and should never be considered an SSN number. Even when asked by creditors you should state that it is a CPN/SCN number. It is illegal to tell any creditor that it is an SSN number.
2. It is illegal to obtain a document showing your CPN/SCN as a SSN number, since it is NOT an SSN number.
3. It is illegal to obtain a drivers license from someone other than the Drivers License Bureau. Novelty documents are not legal if you are using them to get any kind of credit or loans with you CPN/SCN.
4. You cannot use your CPN/SCN for employment NO -
5. You cannot file taxes or pay taxes using your CPN/SCN. NO
6. You cannot check a CPN against something that checks SSNs because it is NOT an SSN number -
7. YOU must pay any debt that you have gotten on your SCN/CPN it is your responsibility to do so or you are defrauding the creditors which is ILLEGAL.
Do not let anyone tell you differently when it comes to the legality of CPN/SCNs. Yes you can use them for credit, yes you can do a lot of things, but there is a thin line between legal and illegal. DONT cross it.