17 November 2010

US Board of Appeals (BPAI) Rejects Cryptographic Method as Abstract Idea

Signature of Queen Elizabeth I (1533-1603)
In early October 2010, the US Board of Patent Appeals and Interferences (BPAI) issued three interesting decisions relating to computer-implemented inventions in the US, namely (i.) Ex parte MacKenzie, App. No. 10/183,900, (ii.) Ex parte Kelkar, App. No. 10/629,448, and Ex parte Venkata, App. No. 11/182934. A brief overview of these opinions can be found on Dennis Crouch’s Patently-O blog. 

In Ex parte MacKenzie (Appeal No. 2009-7332), the applicant presented independent method claims 1 and 9 and corresponding independent apparatus claims 17 and 18. Theses claims sought protection for a technique for sharing the DSA signature function, so that two parties can efficiently generate a DSA signature with respect to a given public key but neither can alone. The Board rejected the claims under 35 U.S.C. § 101, since the method was directed to an abstract idea, as affirmed by the US Supreme Court in Bilski v. Kappos, and remanded the case to the examiner for further prosecution. 

Rejected claim 1 reads as follows:
1. A method for use in a device associated with a first party for performing a signature operation on a message substantially based on the digital signature algorithm (DSA), the method comprising the steps of:
  • generating in the first party device a first component associated with the signature operation based on assistance from a device associated with a second party, wherein the assistance from the second party device is received as a first message from the second party device;
  • transmitting the first component to the second party device;
  • generating in the first party device a second component associated with the signature operation based on further assistance from the second party device, wherein the further assistance from the second party device is received as a second message from the second party device, wherein the second message comprises results generated using the transmitted first component; and
  • outputting a form of the first component and the second component as a result of the DSA signature operation.
Besides the fact, that the unpatentability of abstract ideas was recently reaffirmed by the US Supreme Court in Bilski v. Kappos, the Board’s decision specifically relied on the findings that
  • subject permitted within 35 U.S.C. § 101 must fall within one of the four exclusive statutory categories, machine, manufacture, process, or composition of matter;
  • a “signal” cannot be patentable subject matter because it is not within any of the four categories (In re Nuijten, see also here and here);
  • the Supreme Court has held that excluded from such patent protection are laws of nature, natural phenomena, and abstract ideas (Diamond v. Diehr, see also here);
  • An idea of itself is not patentable (Gottschalk v. Benson, see also here and here);
  • a claim that recites no more than software, logic or a data structure (i.e. an abstraction) does not fall within any statutory category (In re Warmerdam); and
  • abstract software code is an idea without physical embodiment (Microsoft Corp. v. AT&T Corp., see also here and here).
With this background in mind, the Board entered a new ground of rejection under 35 U.S.C. § 101 as being directed to non-statutory subject matter, because the claims relate an abstract process.

The Board observed that the preamble of above claim 1 recites a “method […] for performing a signature operation on a message substantially based on the digital signature algorithm (DSA)” and that
the claimed invention is directed to software per se, abstract ideas, abstract intellectual concepts and the like, including mathematical variables as software components, such as the claimed first component and second component and a mathematical algorithm, such as the claimed [method].
The Board further concluded that
the claimed method sets forth abstract intellectual concepts embodying the invention, which is fundamentally directed to a mathematical algorithm. To the extent recited in claim 1, the first and second components appear to be variables in a mathematical equation (DSA algorithm) that is presented in combination with a nominal claim to generic structures, such as the claimed “devices.
Analogously, corresponding independent apparatus claims 17 and 18 were also concluded to merely represent a mathematical algorithm (the DSA) in combination with generic structures, such as an apparatus, processor, and memory that are each modified by a statement of intended use. The board thus emphasised that clever claim drafting involving the nominal addition of generic structures cannot circumvent the “abstract idea” principle articulated by the Supreme Court in Bilski v. Kappos, so even when a claim appears to apply an idea or concept in combination with a nominal claim to generic structure(s), one must ensure that it does not in reality seek patent protection for that idea in the abstract.

Moreover, claims 17 and 18 were found to be limited neither to a tangible practical application in which the application of the mathematical algorithm results in a real-world use nor to encompass not substantially all practical applications of the mathematical algorithm (cf. Ex parte Gutta, see also here).

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