Database methodology for searching encrypted data records

Abstract

A method for increasing sargability of encrypted records to allow for searching of a first column of a first data table for encrypted values containing a search string without having to decrypt all encrypted values involves, for each respective data record in the first data table, accessing an encrypted data value from the first column, decrypting the accessed encrypted data value, generating from the decrypted data value a respective plurality of substrings of various lengths, encrypting each substring of the respective plurality of substrings as an encrypted substring token, and storing each encrypted substring token in association with a reference value for lookup of a corresponding record in the first data table. Subsequently, the first column of the first data table can be searched for encrypted values containing a first search string by encrypting the first search string and searching for encrypted substring tokens matching the encrypted first search string.