Association for Computing Machinery
Proxy re-encryption, abbreviated as PRE, is a cryptosystem which allows the proxy to re-encrypt a ciphertext without accessing the underlying message. The re-encryption protocol should be key independent to avoid compromising the private keys of the sender and the recipient. PRE should also be secure from signature re-usability, where unreliable proxies store and re-use the signatures without the authorization of the signature bearer. This is achieved by ensuring that PRE algorithm is unidirectional, key independent and the signature is dynamic. The proposed approach uses identity and secret key to prevent plain text and collusion attacks while ensuring that the delegator approves every signature used on his behalf.