Low-overhead architecture for security tag

A security-tagged architecture is one that applies tags on data to detect attack or information leakage, tracking data flow. The previous studies using security-tagged architecture mostly focused on how to utilize tags, not how the tags are implemented. A naive implementation of tags simply adds a tag field to every byte of the cache and the memory. Such technique, however, results in a huge hardware overhead. This paper proposes a low-overhead tagged architecture. We achieve our goal by exploiting some properties of tag, the non-uniformity and the locality of reference. Our design includes a use of uniquely designed multi-level table and various cache-like structures, all contributing to exploit these properties. Under simulation, our method was able to limit the memory overhead to 1.8%, where a naive implementation suffered 12.5% overhead.