The present disclosure relates to systems and methods for random fill caching for secure cache memories. The system dynamically de-correlates fetching a cache line to the processor from filling the cache with this cache line, due to a demand memory access, in order to provide greater security from information leakage due to cache side-channel attacks on cache memories.

The system includes a random fill engine which includes a random number generator and an adjustable random fill window. A random fill cache sends a plurality of requests to the next level of memory including a normal fill request, a “nofill” request, and a random fill request, to provide added security for the cache memory. In a “nofill” request, a demand missed cache line will not be filled in the cache. Instead, a randomly selected cache line within the neighborhood window of the demand missed cache line address will be filled into the cache, called a random fill request. The system also supports “normal” requests that use the conventional demand fill policy. Also provided is an adaptive random fill caching system which dynamically adapts the random fill window to a wide variety of computational workloads. Systems and methods for cache prefetching to improve system performance using adaptive random fill prefetching and random fill prefetching are also provided.