Modified Permuterm Index for Accurate Encrypted Wildcard Search

The patent applies preliminary action by pre-computing and storing wildcard search results in the index during the indexing phase. Instead of performing wildcard matching at query time (which would require decryption and post-processing), the system pre-generates all possible wildcard variations and stores them in the encrypted index. This allows accurate wildcard searches to be performed directly on encrypted data without generating false positives that need later removal.

The patent uses copying by creating and storing multiple versions of index entries corresponding to different wildcard patterns in the encrypted index. Instead of performing post-processing on decrypted data, the system pre-creates copies of the data with wildcard variations already applied and stored in the index. This allows the search to directly compare encrypted queries against these pre-computed encrypted copies, eliminating the need for decryption during post-processing while maintaining security.

The patent applies preliminary action by performing the computationally intensive wildcard pattern generation and matching setup during the indexing phase rather than at query time. The system pre-computes all wildcard variations and stores them in the encrypted index structure, which shifts the processing load to the indexing stage. During actual searches, the pre-computed index enables efficient direct comparison without generating false positives or requiring post-processing, thereby improving query processing efficiency.