12. The method of claim 11 , further comprising: determining which patches to provide for the signature generation based on at least one of: an entropy level of a patch, corners identified in a patch, and borders identified in a patch.
18. The method of claim 12 , generating the at least one index further comprising: matching metadata related to the received MMDE against concept structures; and generating the index for the received MMDE, for each matching concept structure; and storing a plurality of indices generated for the plurality of MMDEs in the concept database.