Trusted Knight Corp. v. International Business Machines Corp. (Fed. Cir. Mar. 7, 2017) (nonprecedential)
In this case, the Federal Circuit affirmed a district court decision invalidating three patent claims as indefinite under the Supreme Court's Nautilus decision. The patent at issue relates to protecting computers against key logging malware.
The first term in dispute was "in response to the software key logging through the API stack to an internet communication port." The district court held this term indefinite because it is unclear what "in response to the software key logging" requires. On appeal, the plaintiff argued that this limitation does not require responding to or detecting actual malware on a user's computer. The Federal Circuit found this argument supported by the patent specification, which states "[t]he solution of the present invention does not depend on detection of malware at all." In the underlying district court decision, the district court had asked what is happening "in response to the software key logging" if the invention is not responding to malware. The plaintiff responded to this question during the appeal by arguing that the invention responds to the threat of malware. The Federal Circuit rejected this argument as the claim limitation does not "refer to the 'threat' or 'potential presence' of key logging; rather it refers to key logging." The Federal Circuit then held that meaning of this claim term is not reasonably certain and the clams containing this term are therefore indefinite.
The second term in dispute was "a process of passing the encrypted data to a 3-ring level where a hook inserted by a hook-based key logger." The parties agreed that this claim term contains a typographical error. Specifically, the term is missing a verb between "hook" and "inserted." The district court held it could not correct this error because the correction was subject to reasonable debate. The plaintiff argued that the verb "is" should be inserted between "hook" and "inserted." But the district court found that the claim could also be corrected by inserting "could be" between "hook" and "inserted." The Federal Circuit determined that the plaintiff's proposed correction would suggest that the "process of passing the encrypted data to a 3-ring level" only occurs when a hook is actually inserted, but "the specification emphasizes that the invention operates regardless of the presence or detection of malware." The Federal Circuit then determined that the district court's alternative correction "would seem to be consistent with the specification" but "would create a different claim scope than [plaintiff's] proposed construction of adding 'is.'" As the proposed correction to the claim was subject to reasonable debate, the Federal Circuit held the claim limitation is not amenable to correction and does not inform those skilled in the art about the scope of the invention with reasonable certainty. The Federal Circuit thus held the claim indefinite.