Pattern Matching over Encrypted Data with a Short Ciphertext.

In this paper, we propose a new searchable encryption with shiftable trapdoor (SEST) scheme to enable pattern matching over encrypted data. In the proposed scheme, data is encrypted per character and the trapdoor for searching can be shifted. This implies that the trapdoor can be created over any string, which is not necessarily pre-defined. Also, it does not require any additional data tokenization method, which will expand the ciphertext size. As ciphertext size increases with the size of data, it is imperative to reduce ciphertext size in the SEST scheme as the matching operation requires expensive pairing computations proportional to the ciphertext length. Our work reduces the ciphertext size by up to 50% of the state-of-art scheme in this research domain while maintaining the same level of search efficiency.