As reference to solidity sample codes on the web, most of solidity sample codes relates to crowdfunding, voting, bidding focusing on the transferring, exchange or record of numeric value.

If I would like to handle mortgage (installment) or online shopping, one side holds value (money) and another side holds an physical/tangible asset.

How does the solidity represent the status and ownership transferring of physics or tangible asset ownership? (such as property, or the product).

1 Answer 1


Since I am new to developing smart contract, I will answer your question in a somewhat abstract manner. Consider the real world example of automobile titles and a private auto sale. The seller agrees to sign the title over to the buyer in exchange for a sum of money exchanged from the buyer to the seller. There are two compensating value exchanges (dollars from buyer to seller and signed title from seller to buyer).

In the blockchain world, you understand the concept of owning ether. In the same way, the automobile title could be represented as a token that the seller has received from an earlier transaction when the auto was purchased. The AutoTitle Token would be equivalent to an unspent transaction in the sellers account, and the seller can prove they own the auto by proving they control the account in which the transaction remains (by proving knowledge of the private key). To facilitate the sale, a smart contract could be written that requires BOTH a signed ether transaction (from the buyer to the seller) and a signed AutoTitle Token transaction (from the seller to the buyer). If BOTH transactions are not completed, the smart contract can stipulate that any input transactions that were approved but not completed (sitting in escrow) would be reversed.

Again, I am too new to smart contracts to show you sample code, but in principle that is how the commercial ethereum contracts operate.

  • Thank you @Jim K Both seller and buyer who uses the DApp should own Ether for buying the asset and paying the transaction fee (Gas). Or The owner of the Smart Contract will pay for the transaction (Solidity method calls) between buyer & seller ?
    – Sabha B
    Commented Jul 11, 2017 at 17:48
  • 1
    A Smart Contract may own Ether, but this is an anti-pattern that should be avoided. There is no default mechanism for the smart contract owner (contract creator) to submit Ether to a transaction, though I can see how a smart contract could be written that way, but it would be a rare scenario. The transaction fee (Gas) is always paid by the submitter of the transaction.
    – Jim K
    Commented Nov 10, 2017 at 19:56
  • I would like to amend my answer to indicate that the AutoTitle Token would be represented by an NFT that can be passed from owner to owner in a blockchain transaction.
    – Jim K
    Commented Aug 3, 2023 at 14:44

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