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.

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.

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.

But he faults its core idea that the RSA algorithm is somehow fundamentally flawed. “I’d say all cryptography relies on good true random-number generation.