Efficient and Secure Encryption Adjustment for JSON']JSON Data

Querying over data protected by multi-layered encryption requires encryption level adjustments. Different layers of encryption enable different sets of operations over encrypted data at the expense of possibly reducing protection levels and releasing some information about the data. Trade-offs between functionality and data security are non-trivial and have been addressed in previous work for various data models. In this paper, we consider encryption level adjustments for JSON-formatted data and propose new adjustments methodologies, based on sorted criteria and on update-aware principles. Sorted criteria are used to limit the number of encryption layers adjusted, while update-aware adjustments limit the number of updated values. We report on the empirical evaluation of the policies and show that they improve over previously proposed policies in terms of communication costs, exposing information, and performance.