10. The method of claim 1 , wherein, if the result of the multiplication between the query matrix and a given resultant vector is 1 in at least one row, the method comprises a step of sending that resultant vector to the querier as one of wanted resultant vectors.
10. The method of claim 1 , wherein, if the result of the multiplication between the query matrix and a given resultant vector is 1 in at least one row, the method comprises a step of sending that resultant vector to the querier as one of wanted resultant vectors. 12. The method of claim 10 , further comprising a step of identifying in a second secret conversion table which document is associated with the wanted resultant vector.