The use of RSA is practically ubiquitous today. It is currently used in a wide variety of products, platforms, and industries around the world. It is found in many commercial software products and is planned to be in many more. It is built into current operating systems by Microsoft, Apple, Sun, and Novell. In hardware, RSA can be found in secure telephones, on Ethernet network cards, and on smart cards. In addition, RSA is incorporated into all of the major protocols for secure Internet communications, including SSL (see Question 134), S-HTTP (see Question 133), SEPP, S/MIME, S/WAN, STT and PCT (see Question 136). It is also used internally in many institutions, including branches of the U.S. government, major corporations, national laboratories, and universities.
As of the time of this publication, RSA technology is licensed by about 150 companies. The estimated installed base of RSA encryption engines is around 20 million, making it by far the most widely used public-key cryptosystem in the world. This figure is expected to grow rapidly as the use of the Internet and the World Wide Web grows at a blistering pace. For a partial list of software and hardware products implementing RSA, see The 1995 Computer Security Products Buyer's Guide. A more complete list of RSA licensees and OEM products can be found at < http://www.rsa.com/>.