[johnpaulett]

Granted, I am neither a patent expert nor a homomorphic encryption expert, but how is this patentable since homomorphic encryption is just a mathematical formula?

From Wikipedia [1]: Homomorphic encryption is a form of encryption where a specific algebraic operation performed on the plaintext is equivalent to another (possibly different) algebraic operation performed on the ciphertext

[1]: http://en.wikipedia.org/wiki/Homomorphic_encryption

[brlewis]

In theory, a mathematical formula is not patentable. In theory, a patent that precludes every practical use of a mathematical formula is invalid. In theory, a patent is required to be specific enough that a person of ordinary skill in the field could use it to reduce the invention to practice (a requirement that no homomorphic encryption patent could possibly meet.)

By "theory" I mean statute and Supreme Court precedent. These are just theory, not law. Law is not what the legislature says or what the Supreme Court says. Law is what happens to you in court.

[mistercow]

The general rule in the US patent system is that mathematical formulas are not patentable, and so neither are algorithms. But a device or system that uses an algorithm is patentable. So they don't patent the algorithm itself, but "a method and system". In other words they're patenting the idea of running the algorithm on a computer.

Insane, yes, but upheld by current precedent.

[brlewis]

In the Bilski case, the Supreme Court reminded us that Benson, Flook and Diehr are still good precedent. So patenting the idea of running the algorithm on a computer is also not upheld by current precedent.

Oh, they also said to ignore State Street, the precedent that upholds software patents. But they're just the Supreme Court. Nobody listens to them in this area anyway. I know I sound sarcastic, but I'm serious.

[mistercow]

I had forgotten about Bilski. Still, if the courts don't listen to a precedent, is it really a precedent?

[excuse-me]

Yes, all you have to do is hire more lawyers than Apple/IBM/Microsoft or whoever.

Go to court in East Texas and persuade a jury that a bunch of damn Yankee judges up there in Washington know better than an honest American corporation.

[tptacek]

As I understand it from talking to patent lawyers: they're patenting the specific use of the algorithm, not the algorithm itself. It's "use of such-and-such formula to accomplish security goal X in an electronic computer system" that's at play, not the fundamental math.

[brlewis]

Just for fun, next time a patent lawyer tells you that, ask them to explain how such a patent is distinguished from Flook's patent. http://en.wikipedia.org/wiki/Parker_v._Flook

[tptacek]

Will do!

[jandrewrogers]

That is not quite correct. You cannot patent something that precludes the use of a mathematical concept but you can patent a method for applying a mathematical concept. For example, you cannot patent "sorting" but you can patent a "bubble sort algorithm" because the latter is one of an infinite number of methods in which the mathematical concept of sorting can be implemented. The RSA patent did not prevent people from using public key cryptography (either in theory or in practice), only one particular algorithm for implementing such a concept.

Algorithm patents are allowed in most countries, contrary to popular belief; when most people talk about "software patents" they are actually talking about business process patents which rarely exist outside the US. Actual algorithms are recognized as a direct abstraction of electronic circuit designs and electronic circuit designs are widely recognized as patentable subject matter.

(Any consistent application of an "algorithms are mathematics" argument would exclude all currently patentable subject matter, for better or worse. I do not have a strong opinion one way or the other but it is worth pointing out because this fact is lost in many discussions of patents.)

[brlewis]

Benson's patent was for a particular algorithm, not an abstract concept, yet it was found invalid: http://en.wikipedia.org/wiki/Gottschalk_v._Benson

The RSA patent didn't make it through the patent system by claiming a particular algorithm; it made it through by including the hardware: http://en.wikipedia.org/wiki/RSA_(algorithm)

See also http://en.wikipedia.org/wiki/Freeman-Walter-Abele_Test

[excuse-me]

Long multiplication isn't patentable The use of a device (such as a pen) to write down the values as you do the multiplication is patentable