A computer system comprising: one or more computer processors; and a computer-readable storage medium comprising instructions, that when executed, cause the one or more computer processors to: receive, at a verification service, a description for a combination of a set of ranges (206-1,..., 206-6) within content available for download, wherein the set of ranges are not sequentially located in the content that a client device (104-N) has downloaded; determine if at least a first portion of the combination of the set of ranges has been received in a prior request; when at least the first portion of the combination of the set of ranges has been received, retrieve a first set of verification values that represent subsets of content corresponding to the first portion of the combination of the set of ranges; when at least a second portion of the combination of the set of ranges has not been received, generate a second set of verification values using subsets of content corresponding to the second portion of the combination of the set of ranges; store the second set of verification values for each of the second portion of the combination of the set of ranges separately in the storage for use in processing subsequent requests for ranges within pieces of the content; and send the one or more of the first set of verification values and the second set of verification values to the client device to allow the client device to verify subsets of content downloaded by the client that correspond to the set of ranges. one or more computer processors; and a computer-readable storage medium comprising instructions, that when executed, cause the one or more computer processors to: receive, at a verification service, a description for a combination of a set of ranges (206-1,..., 206-6) within content available for download, wherein the set of ranges are not sequentially located in the content that a client device (104-N) has downloaded; determine if at least a first portion of the combination of the set of ranges has been received in a prior request; when at least the first portion of the combination of the set of ranges has been received, retrieve a first set of verification values that represent subsets of content corresponding to the first portion of the combination of the set of ranges; when at least a second portion of the combination of the set of ranges has not been received, generate a second set of verification values using subsets of content corresponding to the second portion of the combination of the set of ranges; store the second set of verification values for each of the second portion of the combination of the set of ranges separately in the storage for use in processing subsequent requests for ranges within pieces of the content; and send the one or more of the first set of verification values and the second set of verification values to the client device to allow the client device to verify subsets of content downloaded by the client that correspond to the set of ranges. receive, at a verification service, a description for a combination of a set of ranges (206-1,..., 206-6) within content available for download, wherein the set of ranges are not sequentially located in the content that a client device (104-N) has downloaded; determine if at least a first portion of the combination of the set of ranges has been received in a prior request; when at least the first portion of the combination of the set of ranges has been received, retrieve a first set of verification values that represent subsets of content corresponding to the first portion of the combination of the set of ranges; when at least a second portion of the combination of the set of ranges has not been received, generate a second set of verification values using subsets of content corresponding to the second portion of the combination of the set of ranges; store the second set of verification values for each of the second portion of the combination of the set of ranges separately in the storage for use in processing subsequent requests for ranges within pieces of the content; and send the one or more of the first set of verification values and the second set of verification values to the client device to allow the client device to verify subsets of content downloaded by the client that correspond to the set of ranges.