Is compelled execution of a handwriting exemplar a violation of privacy under the Fourth Amendment?

Dionisio relied on Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967), which held that the Fourth Amendment provides no protection for what "a person knowingly exposes to the public, even in his home or office." The physical characteristics of a person's voice or handwriting are constantly exposed to the public, hence no intrusion into a person's privacy results from the compelled execution of a handwriting exemplar. We find no Fourth or Fifth Amendment violation to exist.