Considering electronic rights trading, especially P2P trading of rights among users, high usability is necessary for protocols as well as strong safety. However, in some protocols, they need several synchronous bi-directional transactions to achieve strong safety, but it offers low usability. We propose a novel rights trading protocol which enables simple and secure authentication escrow with asynchronous two transactions. In our protocol, the authentication information of the owner is hidden into trade declaration with the identifier of the right and trading conditions like price the owner requires, and the declaration is dispersed into a pair of shares using polynomial function. These shares include all the information and anyone can reconstruct a part of trade declaration, but no one except rights manager and the owner himself can reconstruct the authentication information. In this paper we describe detailed outline of the protocol and discuss the safety and usability of it.