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, S-HTTP, SEPP, S/MIME, S/WAN, STT and PCT. It is also used internally in many institutions, including branches of the U.S. government, major corporations, national laboratories, and universities.
RSA is part of many official standards worldwide. The ISO (International Standards Organization) 9796 standard lists RSA as a compatible cryptographic algorithm, as does the ITU-T X.509 security standard. RSA is part of the Society for Worldwide Interbank Financial Telecommunications (SWIFT) standard, the French financial industry's ETEBAC 5 standard, and the ANSI X9.31 draft standard for the U.S. banking industry. The Australian key management standard, AS2805.6.5.3, also specifies RSA.
RSA is the most widely used public-key cryptosystem today and has often been called a de facto standard. Regardless of the official standards, the existence of a de facto standard is extremely important for the development of a digital economy. If one public-key system is used everywhere for authentication, then signed digital documents can be exchanged between users in different nations using different software on different platforms; this interoperability is necessary for a true digital economy to develop. Adoption of RSA has grown to the extent that standards are being written to accommodate RSA. When the U.S. financial industry was developing standards for digital signatures, it first developed ANSI X9.30 to support the federal requirement of using the Digital Signature Standard. They then modified X9.30 to X9.31 with the emphasis on RSA digital signatures to support the de facto standard of financial institutions.
RSA is patented under U.S. Patent 4,405,829, issued September 20, 1983 and held by RSA Data Security, Inc. of Redwood City, California; the patent expires 17 years after issue, in 2000. RSA Data Security has a standard, royalty-based licensing policy which can be modified for special circumstances. The U.S. government can use RSA without a license because it was invented at MIT with partial government funding.
Export of RSA falls under the same U.S. laws as all other cryptographic products.
RSA used for authentication is more easily exported than when it is used for privacy. In the former case, export is allowed regardless of key (modulus) size, although the exporter must demonstrate that the product cannot be easily converted to use for encryption. In the case of RSA used for privacy (encryption), the U.S. government generally does not allow export if the key size exceeds 512 bits.