Security vulnerability in a non-interactive ID-based proxy re-encryption scheme
Recently, a non-interactive identity-based proxy re-encryption scheme was proposed for achieving CCA-security. In the paper, we show that the identity-based proxy re-encryption scheme is unfortunately vulnerable to a collusion attack. The collusion of a proxy and a malicious user enables two parties to derive other honest user's private key and thereby decrypt ciphertexts intended for the honest user. (C) 2009 Elsevier B.V. All rights reserved.
identity-based proxy re-encryption collusion attack cryptography cca-security