Patent Document ID: 9177127
Application ID: 13731367

Base Claim:
1. A method of generating a knowledge-based authentication (KBA) question configured to be provided to a person requesting authentication as a user that is a member of an organization, the KBA question including a query, a correct answer corresponding to the query, and a set of incorrect answers corresponding to the query, the method comprising: producing, by a processor of a KBA system, personal information management (PIM) data from communications involving members of the organization, PIM data from communications involving a particular member of the organization including a reference to the particular member; obtaining, by the processor, a set of user facts from the PIM data that includes a reference to the user; storing the set of user facts in a memory of the KBA system; generating, by the processor, a set of confounders from user facts of the set of user facts stored in the memory of the KBA system; and selecting, by the processor, incorrect answers from the set of confounders to form the set of incorrect answers corresponding to the query of the KBA question; wherein the method further comprises: producing the query and the corresponding correct answer of the KBA question from a first subset of the user facts; wherein generating the set of confounders from the user facts includes: producing the set of confounders from a second subset of the user facts, the second subset of the user facts being distinct from the first subset of the user facts; wherein the PIM data includes a set of emails, each email of the set of emails including a header containing i) a user identifier that identifies the user, and ii) a context that identifies subject matter of the email; wherein producing the query and the corresponding correct answer of the KBA question includes: extracting the context from the header of an email of a first subset of emails of the set of emails, the first subset of user facts being derived from the first subset of emails; wherein producing the set of confounders includes: extracting a confounder of the set of confounders from the header of an email of a second subset of emails of the set of emails, the second subset of user facts being derived from the second subset of emails; and wherein the method further comprises: arranging the user identifier, the context, and the set of confounders in an entry in a confounder database.

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Claim 2:
2. A method as in claim 1 , wherein arranging the user identifier, the context, and the set of confounders in an entry in a confounder database includes: in the confounder database, storing the set of confounders in an inverted list that is indexed by the user identifier and the context.