Web Security and Commerce

U.S. Restrictions on Cryptography

The legal landscape of cryptography is complex and changing all the time. In recent years some restrictions have been eased, while others have been created. In this section, we’ll examine restrictions that result from U.S. patent law, trade secret law, U.S. export restrictions, and national laws of various countries.

Note

These regulations and laws are in a constant state of change, so be sure to consult with a competent attorney (or three) if you will be using cryptography commercially or internationally.

Cryptography and the U.S. Patent System

Patents applied to computer programs, frequently called software patents, are the subject of ongoing controversy in the computer industry.

Some of the earliest and most important software patents granted by the U.S. Patent and Trademark Office were in the field of cryptography. These software patents go back to the late 1960s and early 1970s. Although computer algorithms were widely thought to be unpatentable at the time, the cryptography patents slipped in because they were written as patents on encryption devices that were built in hardware. Indeed, most early encryption devices were built in hardware because general-purpose computers at the time simply could not execute the encryption algorithms fast enough in software.

IBM obtained several patents in the early 1970s on its Data Encryption Algorithm, which went on to become the DES standard. Later in that decade, all of the pioneers in the field of public ...