Oblivious transfer with a memory-bounded receiver

We propose a protocol for oblivious transfer that is unconditionally secure under the sole assumption that the memory size of the receiver is bounded. The model assumes that a random bit string slightly larger than the receiver´s memory is broadcast (either by the sender or by a third party). In our construction, both parties need memory of size in θ(n^2-2α) for some α<½, when a random string of size N=n^2-α-β is broadcast, for α>β>0, whereas a malicious receiver can have up to γN bits of memory for any γ<1. In the course of our analysis, we provide a direct study of an interactive hashing protocol closely related to that of M. Naor et al. (1998)