As far as I know, not yet. It's not even publicly known how exactly the deduplication API works. For example: is the hash enough to "prove" you have a file? Or

As far as I know, not yet. It's not even publicly known how exactly the deduplication API works. For example: is the hash enough to "prove" you have a file? Or do you need the file size (and potentially other properties, such as the first block) as well? The only way to find this out would be to look at the protocol that the proprietary client uses.