As far as I understood, PRE claims to hide the underlying message from being read by the proxy. Why can't the proxy simple use a public key of himself as target?

  • 3
    $\begingroup$ He could. But as computing a re-encryption key requires the secret key of the sender, the sender would have to compute that key and thus "allow" reencryptions. And one assumes that the sender will wisely choose for whom to compute a re-encryption key. $\endgroup$
    – DrLecter
    Jul 3, 2018 at 12:58
  • $\begingroup$ Ok, so the key component of PRE is, that the re-encryption is a one time key and cannot be used any more? $\endgroup$
    – Techradar
    Jul 4, 2018 at 7:00
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    $\begingroup$ Nope, ist not a one-time key but every re-encryption key is specifically computed from the secret key of a specific sender and the public key of a specific receiver. Only if the proxy tricks you in computing a re-encryption key for him, then you have a problem. $\endgroup$
    – DrLecter
    Jul 4, 2018 at 12:30


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