@misc{cryptoeprint:2011:208,
    author = {Jian Weng and Yunlei Zhao},
    title = {Direct Constructions of Bidirectional  Proxy Re-Encryption with Alleviated Trust in Proxy},
    howpublished = {Cryptology ePrint Archive, Report 2011/208},
    year = {2011},
    url = {http://eprint.iacr.org/2011/208},
}