International Association for Cryptologic Research (IACR)
Abstract
In 1980, Hellman introduced a time/memory trade-off (TMTO) algorithm satisfying
the TMTO curve TM2=N2, where T is the online time, M is the memory and N is the size
of the search space. Later work by Biryukov-Shamir incorporated multiple data to
obtain the curve TM2D2=N2, where D is the number of data points.
In this paper, we describe a new table structure obtained by combining Hellman\u27s
structure with a structure proposed by Oechslin. Using the new table structure, we
design a new multiple data TMTO algorithm both with and without the DP method.
The TMTO curve for the new algorithm is obtained to be T3M7D8=N7. This curve is
based on a conjecture on the number of distinct points covered by the new table. Support
for the conjecture has been obtained through some emperical observations. For D>N1/4,
we show that the trade-offs obtained by our method are better than the trade-offs
obtained by the BS method