Asset cards for tracking divisible assets in a distributed ledger

Abstract

A system is provided for tracking units that are divisions of an asset via a distributed ledger. For each asset, the system records an asset card transaction that has an asset card smart contract and an asset card state. The asset card smart contract controls the transfer of ownership of units of an asset. The asset card state identifies the asset, an owner, and a divisibility factor. To transfer units, the asset card smart contract receives a transfer message to transfer a transfer number of units of the asset from a current owner to a new owner. Upon verifying the signature of the transfer message, the asset card smart contract updates the asset card state to reflect the transfer of the transfer number of units from the current owner to the new owner. Each asset card transaction is used to track ownership of units of a single asset.

We claim: 
     
         1 . A method performed by one or more computing systems for tracking units that are divisions of an asset, the method comprising:
 for each of a plurality of assets,
 recording, in an asset card distributed ledger, an asset card transaction, the asset card transaction having an asset card smart contract and an asset card state, the asset card smart contract for controlling transfer of ownership of units of an asset between entities, the asset card state identifying the asset, an owner, and a divisibility factor, the divisibility factor indicating the number of units of the asset, the number of units being initially owned by an initial owner; 
 receiving by the asset card transaction a transfer message to transfer a transfer number of units of the asset from a current owner to a new owner; and 
   under control of the asset card smart contract,
 verifying that the transfer message was signed by the current owner; 
 verifying that the current owner owns at least the transfer number of units of the asset; 
 when the verifications are successful, updating the asset card state to reflect the transfer of the transfer number of units of the asset from the current owner to the new owner 
   wherein each asset card transaction is used to track ownership of units of a single asset.   
     
     
         2 . The method of  claim 1  wherein the asset card state of an asset card transaction specifies a weight of the asset identified by the asset card state. 
     
     
         3 . The method of  claim 1  further comprising, prior to recording an asset card transaction that identifies an asset, recording in an asset distributed ledger an asset transaction having an asset smart contract and an asset state, the asset smart contract for recording in the asset card distributed ledger an asset card transaction for the asset, the asset state including an identifier of the asset and an indicator indicating whether an asset card transaction has been recorded for the identified asset. 
     
     
         4 . The method of  claim 3  wherein the asset state further includes an identification of an asset location of the asset, an indication of whether an asset card transaction can be created for the asset, and a dividable indicator of whether the asset is in a state where it can be divided into units. 
     
     
         5 . The method of  claim 4  wherein an asset is gold, the asset location is in a vault, and the dividable indicator is that the gold has been minted. 
     
     
         6 . The method of  claim 3  wherein the asset distributed ledger and the asset card distributed ledger are the same distributed ledger. 
     
     
         7 . The method of  claim 1  wherein the asset card state includes an owner table and the updating of the asset card state includes updating the owner table to reflect units owned by the current owner and the new owner after the transfer. 
     
     
         8 . The method of  claim 7  wherein the owner table includes a history of all transfers of units of the asset. 
     
     
         9 . The method of  claim 7  wherein the owner table indicates current ownership of units of the asset. 
     
     
         10 . The method of  claim 9  wherein the owner table does not indicate prior ownership of units of the asset. 
     
     
         11 . The method of  claim 1  wherein the asset card distributed ledger is a blockchain distributed ledger. 
     
     
         12 . A method performed by one or more computing systems for transferring ownership of a transfer number of units of an asset, the method comprising:
 receiving a request to transfer ownership of a unit of an asset from a first entity to a second entity, the first entity owning units of assets, each asset represented by an asset card transaction in an asset card distributed ledger, each asset card transaction having an asset card state indicating entities that each own a specified number of units of the asset;   identifying an asset card transaction for which the asset card state indicates that the first entity owns some units of the asset, but not all the units of the asset;   when an asset card transaction is not identified, identifying an asset card transaction for which the asset card state indicates that the first entity owns all the units of the asset; and   transferring ownership of the transfer number of units of the asset of the identified asset card transaction from the first entity to the second entity.   
     
     
         13 . The method of  claim 12  wherein identifying of asset card transactions seeks to identify asset card transactions to maximize the number of the asset card transactions in which all the units of the asset of the asset card transaction are owned by the first entity. 
     
     
         14 . The method of  claim 12  wherein the asset card transactions are recorded in a distributed ledger, each asset card transaction having an asset card smart contract and an asset card state, the asset card smart contract for controlling transfer of ownership of units of an asset between entities, the asset card state identifying the asset, an owner of the asset card transaction, a divisibility factor, and owner data, the divisibility factor indicating the number of units of the asset, the number of units being initially owned by an initial owner, the owner data identifying each entity that owns one or more units of the asset and the number of units owned by each entity. 
     
     
         15 . The method of  claim 14  further comprising, when the first entity is owner of an asset card transaction and owns all the units of the asset of that asset card transaction, transferring ownership of the asset card transaction. 
     
     
         16 . One or more computing systems for tracking units that are divisions of assets, the one or more computing systems comprising:
 one or more computer-readable storage mediums storing computer-executable instructions for controlling the one or more computing system to, for each asset,
 record, in an asset card distributed ledger, an asset card transaction, the asset card transaction having an asset card smart contract and an asset card state, the asset card smart contract for controlling transfer of ownership of units of an asset between entities, the asset card state identifying the asset and a divisibility factor, the divisibility factor indicating the number of units of the asset; and 
 under control of the asset card smart contract, update the asset card state to reflect a transfer of a transfer number of units of the asset from a current owner to a new owner; and 
   one or more processors for executing the computer-executable instructions stored in the one or more computer-readable storage mediums.   
     
     
         17 . The one or more computing systems of  claim 16  wherein the asset card state of each asset card transaction specifies the weight of the asset identified by the asset card state. 
     
     
         18 . The one or more computing systems of  claim 16  wherein the asset card state includes owner data and the instructions that control the one or more computing systems to update the asset card state update the owner data to reflect units owned by the current owner and the new owner after the transfer. 
     
     
         19 . The one or more computing systems of  claim 16  wherein the asset card smart contract conforms to the Ethereum Request for Comment 20 technical standard. 
     
     
         20 . The one or more computing systems of  claim 16  wherein each asset is a gold bar held in a vault. 
     
     
         21 . The one or more computing systems of  claim 20  wherein when an entity who owns all units of a gold bar identified by an asset card transaction takes possession of the gold bar, changing the asset card state to indicate that the gold bar is no longer in the vault. 
     
     
         22 . The one or more computing systems of  claim 16  wherein each asset has an attached identification component for electromagnetically providing an identification number of the asset. 
     
     
         23 . The one or more computing systems of  claim 22  wherein the identification component is a near-field communication component. 
     
     
         24 . The one or more computing systems of  claim 22  wherein the identification component stores a private key for the asset for signing the identification number.