title_body: How are NFTs being minted without smart contract in Cardano? NFTs are being minted in Cardano even without a smart contract in place. How does it ensure that no more token gets minted with the same ID?
upvoted_answer: On Cardano, an NFT doesn't require a Smart Contact, as it is minted as an native asset.
  To make sure a NFT is a really non-fungible, the minter of the native asset is usually locking its minting policy in time. In other words, you mint just one native asset and lock any further minting/burning in time, so it is impossible to increase its supply starting from a specific slot time.
  As an example, have a look at the minting script of nutcoin.