Sending messages securely to protect confidentiality in mobile ad hoc networks is a challenging issue due to the open wireless media, the spacial constraints and the difficulty in establishing strict security mechanisms. To tackle the problem, we have presented a scheme where a source node sends shares of a message at different times. Due to node mobility, the shares will be routed through different intermediate nodes. It is highly unlikely that a particular intermediate node (an eavesdropper) is able to be on (or around) many of these routes and collect enough shares to reconstruct the original message. The scheme is particular suitable for applications that can tolerate long message delays, as those studied in delay tolerant networks. The paper focuses on analyzing the strategies that a node can use in determining the intervals between two shares, and in tuning to applicationspsila requirements on delay bounds. The results provide a guideline for the configuration and the security of the scheme. We further investigate the influence from various mobility models on the security property. The results show big differences among the models and the practical aspect of the scheme. In all, our proposed scheme provides a valuable alternative for delay tolerant applications to enhance message confidentiality.