Evaluation of a Protocol to Prevent Illegal Information Flow Based on Maximal Roles in the RBAC Model

Abstract

In the access control models to make a system secure, a transaction is allowed to read and write an object like a file only if access rights on the object are granted. Suppose a transaction $T_1$ reads data d from a file $f_1$ and then writes the data d to another file $f_2$. Here, another transaction $T_2$ can get the data d by reading the file $f_2$ even if $T_2$ is not granted a read right on the file $f_1$. Here, the read operation issued by the transaction $T_2$ is illegal. In our previous studies, a condition to detect an illegal read operation is defined based on the role-based access control (RBAC) model. Here, once a transaction issues an illegal read operation, the transaction is aborted. However, even if the illegal condition is satisfied for a transaction issuing a read operation, illegal information flow may not occur. In this paper, we newly propose a modified read abortion (MRA) protocol which uses a new condition on maximal roles of role sets. In addition, we consider only maximal roles which include a read right on an object which a transaction can read. In the evaluation, we show the number of transactions aborting can be reduced.