Shared and searchable encrypted data for untrusted servers

Changyu Dong, Giovanni Russello, Naranker Dulay

Research output: Contribution to journalArticlepeer-review

126 Citations (Scopus)
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Current security mechanisms are not suitable for organisations that outsource their data management to untrusted servers. Encrypting and decrypting sensitive data at the client side is the normal approach in this situation but has high communication and computation overheads if only a subset of the data is required, for example, selecting records in a database table based on a keyword search. New cryptographic schemes have been proposed that support encrypted queries over encrypted data. But they all depend on a single set of secret keys, which implies single user access or sharing keys among multiple users, with key revocation requiring costly data re-encryption. In this paper, we propose an encryption scheme where each authorised user in the system has his own keys to encrypt and decrypt data. The scheme supports keyword search which enables the server to return only the encrypted data that satisfies an encrypted query without decrypting it. We provide a concrete construction of the scheme and give formal proofs of its security. We also report on the results of our implementation.
Original languageEnglish
Pages (from-to)367-397
Number of pages31
JournalJournal of Computer Security
Issue number3
Early online date31 May 2011
Publication statusPublished - 2011


  • searchable encryption
  • secure data outsourcing
  • proxy encryption


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