International Association
for Cryptologic Research

\emph{Password-protected secret sharing} (PPSS) schemes allow a user to publicly share this high-entropy secret across different servers and to later recover it by interacting with some of these servers using only his password without requiring \emph{any} authenticated data. In particular, this secret will remain safe as long as not too many servers get corrupted. However, servers are not always reliable and the communication can be altered. To address this issue, a \emph{robust} PPSS should additionally guarantee that a user can recover his secret as long as enough servers provide correct answers, and these are received without alteration. In this paper, we propose new robust PPSS schemes which are significantly more efficient than the existing ones. We achieve this goal in two steps. First, we introduce a \emph{Robust Threshold Secret Sharing Scheme with respect to Random Failures} that allows us to drop the verifiable property of \emph{Oblivious Pseudorandom Functions}. Then, we use this new construction to introduce two new robust PPSS schemes that are quite efficient.