The RSA algorithm works because, when n is sufficiently large, deriving d from a known e and n will be an impractically long calculation — unless we know p, in which case we can use the shortcut.

RSA is a different algorithm with a longer history and a broader adoption, at least in the past. It depends upon the complexity of factoring large numbers.

Despite RSA's gesture, several competitors who have paid royalties for use of the algorithm for up to 17 years, argue that the industry could have done with the patent relaxation earlier.

A recent research paper makes the claim that the RSA cryptographic algorithm can be broken with a quantum algorithm. Skeptics warn: don’t believe everything you read.

The RSA algorithm has become an encryption standard for many e-commerce security applications. The patent for it was issued to MIT on Sept. 20, 1983, and licensed exclusively to RSA Security.

RSA is currently doing an internal review of all of its products to see where the algorithm gets invoked and to change those. A company spokesman said the review is expected to be completed next week.

The RSA algorithm works as follows: First, I find two huge (at least 100 digits each!) prime numbers p and q , and then I multiply them together to get the even bigger number N .