1. A method implemented at least in part by a computer, the method comprising: receiving two or more subtokens, each of a fixed size, the subtokens together representing a larger token of a size larger than the fixed size, data corresponding to the larger token maintained by an offload provider, the larger token representing data that is immutable as long as the larger token is valid; obtaining a key from one or more of the subtokens; and providing evidence of the key to a component of the offload provider at least to obtain a portion of the data represented by the larger token without the portion of the data passing through an initiator that provided the subtokens.