In the United States, the constitutional legality of encryption export regulations has been challenged by three cases, none of which have been settled as of August 1999. Each deals with the ability of a programmer to make his encryption algorithm or software available outside of the country and the possibility that the export restrictions limiting them pose a First Amendment free speech violation.

The three cases are:

Phillip Karn ,a programmer at Qualcomm, was denied a license to electronically export source code for cryptographic algorithms. The disk he wished to export, currently classified as a controlled "Encryption Item," contained code from Applied Cryptography: Protocols, Algorithms, and Source Code in C by Bruce Schneie, a freely exportable book. Karn claims that his case demonstrates the irrationality of current export restrictions of encryption. First, the information available in paper form. Second, many of the algorithms, such as DES, 3DES, and IDEA, are already available abroad. The Enigma algorithm, included on his disk, was used by the Germans during World War II and was broken by the allies. In 1996, Judge Richey of the United States District Court for the District of Columbia granted summary judgement to the government for two reasons. He wrote that, first, any restriction of Karn’s 1^st amendment rights resulting from the export rules was justified as the government was only interested in regulating encryption because of its functional properties. Second, Judge Richey wrote that, under the Arms Export Control Act, export control decisions are not subject to judicial review. Karn appealed to the Court of Appeals for the D.C. Circuit and, after much administration maneuvering, a new judge took over Karn’s case. Judge Oberdorfer granted Karn’s request for an evidentiary hearing on February 18, 1999 under whom Karn filed an amended complaint. More information is available here.

Daniel Bernstein , a mathematician on the faculty of the University of Illinois at Chicago, developed a new cryptographic algorithm that he wished to share with his colleagues in the form of both source code and academic papers. He claims that export regulations have rendered him unable to discuss his work "at mathematical conferences and open public meetings of interested academics, business people, and lay persons." His case most basically asserts that US encryption export regulations are contrary to the "normal process of academic and scientific exchange of ideas and information." After two decisions [1st decision; 2nd decision], Judge Patel of the U.S. District Court for the Northern District of California wrote in her 1997 ruling that encryption software was a protected form of free speech and that the current encryption export controls were therefore unconstitutional. The government appealed the case; the Ninth Circuit Court of Appeals ruled that the Export Administration Regulations (EAR) were, in fact, a restraint of free speech in those cases in which the software in question was expressive and that the EAR did "intentionally retard the progress of the flourishing science of cryptography." The ruling stressed that not all encryption software could be considered expressive. The Justice Department has challenged the ruling, asking for a rehearing with a larger panel of judges.

Peter Junger, a law professor who teaches "Computers and the Law" at Case Western Reserve is the plaintiff of the third case. He sought to post on his web site two of his programs illustrating rudimentary encryption algorithms along with software such as PGP and RSA source code. He filed suit when the Commerce Department denied him permission to export source code in this manner. Judge Gwin from the United States District Court for the Northern District of Ohio granted summary judgement for the government in July 1998 saying that exportation of software is typically non-expressive. The American Civil Liberties Union of Ohio filed a brief for Professor Junger to the United States Court of Appeal for the Sixth Circuit on March 1, 1999. Archived documents related to the case are available here.