"Legal instrument" is a legal term of art[?] that is used for any written legal document such as a property deed[?], a will, an Act of Parliament or a law passed by a competent legislative body in municipal[?] (domestic) or international law. Many legal instruments were written under seal by affixing a wax or paper seal to the document in evidence of the legal exchange value of the document (formerly used as a form of consideration in contract law). Legal instruments have undergone a process of dematerialisation[?] as it is now possible to sign digital documents[?], have them date and time stamped[?], or otherwise verified through various schemes of encryption and document authentication.