(815 ILCS 535/1) (was 720 ILCS 140/1)
    Sec. 1. It is a Class A misdemeanor for any person, including an individual, firm, corporation, association, partnership, joint venture, or any employee or agent thereof, to disclose, or to convey a list of names prepared on the basis of any information obtained in the business of preparing federal or state income tax returns or assisting taxpayers in preparing such returns, including the disclosure or conveyance of such information between separate departments of the same firm, corporation, association, partnership, or joint venture, unless such disclosure or conveyance is within any of the following:
        (a) Consented to in writing by the taxpayer in a
    
separate document.
        (b) Expressly authorized by state or federal law.
        (c) Necessary to the preparation of the return.
        (d) Pursuant to court order.
(Source: P.A. 77-2830.)