Shrinking the Keys of Discrete-Log-Type Lossy Trapdoor Functions
To this day, realizations in the standard-model of (lossy) trapdoor functions from discrete-log-type assumptions require large pub lic key sizes, e.g., about θ(λ2) group elements for a reduction from the decisional Diffie-Hellman assumption (where ,λ is a security parameter). We propose two realizations of lossy trapdoor functions that achieve public key size of only θ(λ) group elements in hilinear groups, with a reduction from the decisional Bilinear Diffie-Hellman assumption. Our first construction achieves this result at the expense of a long common reference string of θ(λ2) elements, albeit reusable in multiple LTDF instantiations. Our second scheme also ,achieves pnblic keys of size θ(λ), entirely in the standard model and in particular without any reference string, at the cost of a slightly more involved construction. The main technical novelty, developed for the second scheme, is a compaet encoding technique for generating compressed representations of certain sequences of group elements for the public parameters.
Xavier Boyen Brent Waters
Institut Montefiore, Université de Liège, Belgium University of Texas at Austin, USA
国际会议
8th International Conference,ACNS 2010(第八届国际应用密码与网络安全大会)
北京
英文
35-52
2010-06-22（万方平台首次上网日期，不代表论文的发表时间）