Proxy re-encryption: Difference between revisions

Revision as of 11:51, 17 February 2017

Revision as of 00:56, 27 January 2018

Line 5:

{{Expert-subject|Cryptography|section|date=June 2007}}

A proxy re-encryption is generally used when one party, say Bob, wants to reveal the contents of messages sent to him and encrypted with his public key to a third party, Chris, without revealing his private key to Chris. Bob does not want the proxy to be able to read the contents of his messages. <ref>Nabeel's Blog, Seen Nov 2014, http://mohamednabeel.blogspot.ca/2011/03/proxy-re-encryption.html</ref>

Bob could designate a proxy to re-encrypt one of his messages that is to be sent to Chris. This generates a new [[Key (cryptography)|key]] that Chris can use to decrypt the message. Now if AliceBob sends Chris a message that was encrypted under Bob's key, the proxy will alter the message, allowing Chris to decrypt it. This method allows for a number of applications such as [[e-mail forwarding]], law-enforcement monitoring, and content distribution.

A weaker re-encryption scheme is one in which the proxy possesses both parties' keys simultaneously. One key decrypts a [[plaintext]], while the other encrypts it. Since the goal of many proxy re-encryption schemes is to avoid revealing either of the keys or the underlying plaintext to the proxy, this method is not ideal.