RSA Cryptography: The Algorithm Keeping Us Safe Online

Online shopping is an essential component of today’s world.

With a few clicks and the input of a handful of numbers, transactions can be completed in just minutes. During busy holiday seasons especially, consumers are increasingly making purchases online. As customers prepare for events like Cyber Monday and the upcoming December holidays, it’s helpful to recognize the technology that enables successful and secure e-commerce.

The Technology

While the infrastructure behind RSA cryptography is complex, understanding its basic elements can be helpful in protecting yourself online.

At its core, RSA is the world’s most widely used public-key cryptography method for securing communication on the internet. Cryptography involves the process of encoding information, and public-key cryptography uses pairs of keys (public and private) to share information. The mathematical properties of the RSA algorithm require that a message encrypted with a public key, which can be shared with everyone, may only be decrypted by a private key, which must be kept secret.

Unlike older methods that required securely exchanged keys to encrypt and decrypt messages, RSA provides a method for encryption and decryption without both parties needing a shared secret key. Several mathematical concepts including trapdoor functions, totient functions and generating primes are involved in the public key encryption process.

Once two entities set up their own key pairs and share the public key with one another, the sender that has the public key of their recipient can use it to encrypt the data they want to keep secure. Once that data has been encrypted with a public key, it can only be decrypted by the private key from the same key pair. When the recipient receives the encrypted message, they use their private key to access the data.

RSA can also mark messages with a digital signature and allows originators to create messages intelligible only to intended recipients. For this reason, third parties intercepting such transmissions would find them difficult to decipher. RSA’s capabilities include functions such as encrypting internet credit card transactions, securing emails and authenticating phone calls.

The Inventors

In 1977, three MIT faculty members introduced the RSA algorithm that profoundly changed how we exchange digital information.

National Inventors Hall of Fame® (NIHF) Inductees Ron Rivest, Adi Shamir and Leonard Adleman – whose surname initials form RSA – spent a year collaborating on their public-key encryption code. The RSA algorithm was the result of many months of trial and error, where computer scientists Rivest and Shamir would propose potential functions while mathematician Adleman would try to poke holes in their ideas. After reading a paper published by NIHF Inductees Whitfield Diffie, Martin Hellman and Ralph Merkle that proposed the need for a public-key encryption scheme with a one-way function, Rivest was inspired to write his own paper on a new idea for an algorithm. It turned out that the algorithm now known as RSA provided a solution to the missing one-way function problem.

For 40 years, RSA has helped secure online transactions and sensitive data against attackers. As technology continues to develop, the hope is that this algorithm will continue to stand the test of time.

Learn More

Interested in learning more about invention? Visit our website, blog and database to discover the groundbreaking inventions created by NIHF Inductees.