A fuzzy sketch with trapdoor

In 1999, Juels and Wattenberg introduce an effective construction of Fuzzy Sketch, i.e., a way of handling errors into string verification. This allows them to consider data varying in time, such as, for instance, answers to a list of subjective questions. To this end, they use an error-correcting code. We show here how to embed a trapdoor into Fuzzy Sketches, reducing to authorized people the ability to correct errors and thus to verify the fuzzy equality to the Fuzzy Sketch.