Abstract: A computer system and method generates a random output stream of bits. The system comprises an initial evolving state produced from one or more initial keys, one or more round functions, and one or more mask tables. Each round function is part of a step in a sequence of steps. Each step applies the respective round function to a current evolving state to produce a respective new evolving state for processing by the next step in the sequence. The first step in the sequence starts b processing the initial evolving state. The mask tables are produced from one or more of the initial keys. Each of the mask tables has one or more masks. The masks are combined, in each respective step, with the respective new evolving state in a combination operation to create a respective step output. The random output stream bits is a concatenation of each of the respective step outputs.

Abstract: Under the present invention, a history of requests for data objects are tracked and maintained in a cache log. Based on the history, certain data objects are prefetched into a cache. When a request for a cached data object is later received, the requested data object can be retrieved from the cache and served to the requesting user. Thus, the latency involved with obtaining the data objects from the appropriate sources is eliminated. Further, under the present invention, discard and refresh rules are assigned to each data object on a class basis. Accordingly, data objects in the cache can be refreshed and/or discarded so that the caching operation can be optimized.