Paper 2006/178 Original: eprint.iacr.org/2006/178 ↗

A New Cryptosystem Based On Hidden Order Groups

Amitabh Saxena
Ben Soh
Abstract

Let $G_1$ be a cyclic multiplicative group of order $n$. It is known that the Diffie-Hellman problem is random self-reducible in $G_1$ with respect to a fixed generator $g$ if $\phi(n)$ is known. That is, given $g, g^x\in G_1$ and having oracle access to a ``Diffie-Hellman Problem solver'' with fixed generator $g$, it is possible to compute $g^{1/x} \in G_1$ in polynomial time (see theorem 3.2). On the other hand, it is not known if such a reduction exists when $\phi(n)$ is unknown (see conjuncture 3.1). We exploit this ``gap'' to construct a cryptosystem based on hidden order groups and present a practical implementation of a novel cryptographic primitive called an \emph{Oracle Strong Associative One-Way Function} (O-SAOWF). O-SAOWFs have applications in multiparty protocols. We demonstrate this by presenting a key agreement protocol for dynamic ad-hoc groups.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2007-03-05: last updated
2006-05-30: published
Short URL
https://ia.cr/2006/178
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2006/178,
      author = {Amitabh Saxena and Ben Soh},
      title = {A New Cryptosystem Based On Hidden Order Groups},
      howpublished = {Cryptology {ePrint} Archive, Paper 2006/178},
      year = {2006},
      url = {https://eprint.iacr.org/2006/178}
}
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