When creating unlockable content you can choose whether the content is downloadable or not.
IMPORTANT: The uploaded and encrypted content is stored permanently on Arweave. If the content is made downloadable this can not be reversed.
However, if you perform a metadata update of the darkblock by re-uploading the exact same file (see Metadata Updates), the “Allow Download” checkbox can be de-seleted. The Darkblock Viewer will then only expose the latest upload of that file. This means the file is no longer downloadable in the Viewer UI, but the original file that was made downloadable is still stored on Arweave and attached to the NFT and so anybody who builds their own Darkblock Viewer could decide to expose those previously uploaded files. Please keep this in mind when selecting the content to be downloadable.