1. A method comprising: determining, by a server optimizer of a communications network, to pre-position a content dataset at a first client terminal in anticipation of a future request for the content dataset by the first client terminal; in response to the determination and prior to any request for the content dataset by the first client terminal: calculating, by the server optimizer, an anticipatory dataset as a function of the content dataset, such that the anticipatory dataset represents at least a portion of the content dataset but cannot be used to reconstruct the content dataset without a keying dataset, the keying dataset being deterministically calculable from the content dataset; and communicating the anticipatory dataset to the first client terminal from the server optimizer over the communications network for anticipatory storage of the anticipatory dataset local to the first client terminal without communicating the keying dataset from the server optimizer and without maintaining the keying dataset at the server optimizer; receiving a content request at the server optimizer issued by the first client terminal for the content dataset, the receiving being subsequent to the communicating the anticipatory dataset to the first client terminal; and in response to the receiving: calculating the keying dataset as a function of the content dataset at the server optimizer; and communicating the keying dataset from the server optimizer to the client terminal for use by the first client terminal in locally reconstructing the content dataset as a function of the keying dataset and the anticipatory dataset.