LAUSR

The problem of multilevel diversity coding with secure regeneration is revisited. Under the assumption that the eavesdropper can access the repair data for all compromised storage nodes, Shao et al. provided a precise characterization of the minimum-bandwidth-regeneration (MBR) point of the achievable normalized storage-capacity repair-bandwidth tradeoff region. In this paper, it is shown that the MBR point of the achievable normalized storage-capacity repair-bandwidth tradeoff region remains the same even if we assume that the eavesdropper can access the repair data for some compromised storage nodes (defined as the type II compromised nodes) but only the data contents of the remaining compromised nodes (defined as the type I compromised nodes), as long as the number of type I compromised nodes is no greater than that of type II compromised nodes.