Concealed Key-Phrase Verification

It is a common task in conversational applications to validate a claimed identity through utterance verification mechanisms; for example, by asking for a password or a challenge question. Sometimes, due to the private nature of the keyphrase, it is desirable to impose restrictions on how this keyphrase, or information that leads to it, is handled during the verification process. In this paper we describe a method where the utterance verification takes place in a concealed way, i.e., in a way that the keyphrase cannot be inferred or obtained directly by an intruder, from the decoding and application artifacts. We achieve this by a novel algorithm based on matrix operations in the verification network's nodes. If the traversed path corresponds to the keyphrase, the annotation converges to the dominant eigenvector of the occluded kernel matrix