I am trying to find the best solution to mint ERC721 NFT tokens when a user presents a specific "voucher". Since this voucher would not only be linked to the blockchain address of its owner but also partly to their real identity, at least the voucher validation step must be performed off chain (as the voucher string cannot be stored on chain for privacy reasons). I was considering a defender autotask webhook for this purpose, but it is not clear to me the level of "trustlessness" this kind of solution would bring. In particular, can the code triggered by an autotask webhook be made public/certified in some way? If not, is there any workaround to reach this goal using autotask, or do you suggest another technology/tool/stack for the purpose?