RSA

The RSA is actually named after the security experts who first described it to the public, which are Ron Rivest, Adi Shamire, and Leonard Adleman.

The cryptographic concept itself refers to a public key cryptography algorithm. This is the first algorithm known in the IT security industry that's deemed appropriate for both encryption and signing.

More to the point, it is believed by many experts to be the one of the pioneering advances in the public key cryptography field.

RSA is quite popular in terms of electronic commerce protocols and other similar applications; when used with updated implementations and sufficiently long keys, it's believed to be one of the most secure algorithms presently in existence.

RSA 1973 History

Back in 1973, an equivalent system to RSA was first described by British Mathematician Clifford Cocks in an internal document for the UK intelligence agency, the GCHQ.

However, because of the low-grade technology and the expensiveness of applying his ideas at the time, this proto-RSA system was never implemented or considered as anything more than a curious little theory for future generations to behold.

Cocks's discovery wasn't divulged to the public until 1998 because of its top-secret nature; besides which, the RSA work of Adleman, Shamir, and Rivest was developed outside of Cocks own work, so although the British Mathematician was the first one to come up with it, credit for modern RSA remains in the hands of the people it was named after.

RSA patent

Back in 1978, the algorithm was explained and defined to the public by the aforementioned Shamir, Rivest, and Adleman at MIT or the Massachusetts Institute of Technology.

The letters of the acronym for the algorithm was derived from the surname initials of two cryptographers (Rivest and Shamir) and one theoretical computer scientist (Adleman) that came up with it as listed in the same order as the paper they presented for it.

In 1983, the patent for "Cryptographic communications system and method" that employed the RSA algorithm was provided to MIT with the U.S. Patent 4,405,829.

Because at the time, the term of the patent ended every seventeen years, the RSA patent would have ended back in September 21, 2000.

Decrypt

However, as early as September 6 of the same year (about two weeks earlier), the algorithm had already been made available as a public domain property by RSA security.

Because the paper that defines RSA was made back in August of 1977, which is before the December 1977 filing date of the application for patenting, rules in much of the rest of the globe prohibited patents in any other place, so only the U.S. Patent remained valid.

Were Cocks' work released to the public at an earlier time, the U.S. Patent may not even be possible either.

Plain RSA is susceptible to a number of attacks.

Cipher texts can be cracked by taking the eth root of the cipher text over integers.

It is also easy to decrypt the initial clear text message using the Chinese remainder theorem following certain variables.