Oblivious random access machine (ORAM) constructions can be used to hide a client's access pattern from a trusted but curious storage server. The privacy provided comes at the cost of increasing communication overhead, storage overhead, and computation overhead of the system. Recursive matrix-based ORAM (RM-ORAM) is a new ORAM construction, which is designed for constrained storage space devices. RM-ORAM significantly reduces the client storage usage by using recursion, while the computational and bandwidth overhead are slightly increased as a tradeoff. However, it can achieve better overall asymptotic performance than other existing ORAM schemes, e.g., recursive Path ORAM. In this paper, we present the construction and its theoretical analysis. In addition, we present how to select the appropriate number of data blocks, which are being downloaded per level of recursion and the appropriate size of reserved space on the client. We provide theoretical security and performance analysis, as well as experimental results to illustrate how RM-ORAM satisfies security requirements and provides improved performance compared with other ORAM schemes.

VoIP (B. Douskalis, 2000) is not appropriate for non-QoS networks, which are the majority of networks in the Internet. It is therefore difficult to guarantee QoS for a VoIP over Virtual Private Networks (VPNs) environment (M. Gunter et al., 1999; Yoshihiro Ito et al., 1998). The paper presents an idea which will alleviate such a limit. The proposed idea is to use a dial up line as an additional connection to elevate degrading bandwidth performance, due to the unreliability of the Internet. However, existing load balancing tools implemented on the router are not appropriate for implementation over a VPN environment. Therefore, the authors propose application routing load balancing (ARLB) for a VPN environment.