International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Public Key Encryption with keyword Search

Dan Boneh
Giovanni Di Crescenzo
Rafail Ostrovsky
Giuseppe Persiano
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Abstract: We study the problem of searching on data that is encrypted using a public key system. Consider user Bob who sends email to user Alice encrypted under Alice's public key. An email gateway wants to test whether the email contains the keyword `urgent' so that it could route the email accordingly. Alice, on the other hand does not wish to give the gateway the ability to decrypt all her messages. We define and construct a mechanism that enables Alice to provide a key to the gateway that enables the gateway to test whether the word `urgent' is a keyword in the email without learning anything else about the email. We refer to this mechanism as <I>Public Key Encryption with keyword Search</I>. As another example, consider a mail server that stores various messages publicly encrypted for Alice by others. Using our mechanism Alice can send the mail server a key that will enable the server to identify all messages containing some specific keyword, but learn nothing else. We define the concept of public key encryption with keyword search and give several constructions.
  title={Public Key Encryption with keyword Search},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography /},
  note={ 12502 received 22 Sep 2003, last revised 24 Mar 2004},
  author={Dan Boneh and Giovanni Di Crescenzo and Rafail Ostrovsky and Giuseppe Persiano},