Paper 2001/088

Improving the trade-off between storage and communication in broadcast encryption schemes

Ignacio Gracia, Sebastià Martín, and Carles Padró


The most important point in the design of broadcast encryption schemes (BESs) is obtain a good trade-off between the amount of secret information that must be stored by every user and the length of the broadcast message, which are measured, respectively, by the information rate $\rho$ and the broadcast information rate $\rho_B$. In this paper we present a simple method to combine two given BESs in order to improve the trade-off between $\rho$ and $\rho_B$ by finding BESs with good information rate $\rho$ for arbitrarily many different values of the broadcast information rate $\rho_B$. We apply this technique to threshold $(R,T)$-BESs and we present a method to obtain, for every rational value $1/R \le \rho_B \le 1$, a $(R,T)$-BES with optimal information rate $\rho$ among all $(R,T)$-BESs that can be obtained by combining two of the $(R,T)$-BESs proposed by Blundo et al.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Unknown where it was published
broadcast encryption
Contact author(s)
matcpl @ mat upc es
2001-10-26: received
Short URL
Creative Commons Attribution


      author = {Ignacio Gracia and Sebastià Martín and Carles Padró},
      title = {Improving the trade-off between storage and communication in broadcast encryption schemes},
      howpublished = {Cryptology ePrint Archive, Paper 2001/088},
      year = {2001},
      note = {\url{}},
      url = {}
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