CRYPTOGRAPHICALLY SECURE PHYSICAL CURRENCY

1 . A device comprising:

precious metal embedded within the device providing an intrinsic value for the device and making the device suitable for use as physical currency; and

processing circuitry configured to:

store information about a transaction hash associated with the device, wherein the transaction hash is derived from prior transactions performed using the device, and

enable comparison of the transaction hash to information about the device that is stored on a distributed ledger.

2 . The device of claim 1 , wherein to enable comparison of the transaction hash to information about the device that is stored on the distributed ledger, the processing circuitry is further configured to:

communicate the transaction hash to a consensus network that maintains the distributed ledger; and

enable the consensus network to compare the transaction hash to the information about the device that is stored on the distributed ledger.

3 . The device of claim 2 , wherein to enable the consensus network to compare the transaction hash to the information about the device that is stored on the distributed ledger, the processing circuitry is further configured to:

enable a smart contract executing on the consensus network to compare the transaction hash to the information about the device that is stored on the distributed ledger.

4 . The device of claim 3 , wherein the processing circuitry is further configured to:

enable the smart contract to determine that the transaction hash is consistent with the information about the device that is stored on the distributed ledger; and

enable the smart contract to authorize a new transaction using the device.

5 . The device of claim 4 , wherein the processing circuitry is further configured to:

store, in memory included within the device, a new transaction hash that is based on the new transaction.

6 . The device of claim 3 , wherein the processing circuitry is further configured to:

enable the smart contract to determine that the transaction hash is not consistent with the information about the device that is stored on the distributed ledger; and

enable the smart contract to deny the new transaction.

7 . The device of claim 1 ,

wherein the device is in the form of a payment card.

8 . The device of claim 1 , wherein the processing circuitry comprises a system on a chip having a secure enclave, and wherein to store the information about the transaction hash, the processing circuitry is further configured to:

store the information about the transaction hash in the secure enclave.

9 . The device of claim 1 ,

wherein the precious metal is of a purity less than bullion-level purity.

10 . The device of claim 1 ,

wherein the precious metal embedded within the device has a weight exceeding a tenth of an ounce.

11 . The device of claim 1 ,

wherein the precious metal embedded within the device has a weight exceeding a hundredth of an ounce.

12 . A method comprising:

embedding precious metal within a device, thereby providing the device with an intrinsic value and making the device suitable for use as physical currency;

storing, within the device, information about a transaction hash associated with the device, wherein the transaction hash is derived from prior transactions performed using the device;

detecting an indication of a new transaction; and

comparing the transaction hash to information about the device that is stored on a distributed ledger.

13 . The method of claim 12 , wherein comparing the transaction hash to information about the device that is stored on the distributed ledger includes:

communicating the transaction hash to a consensus network that maintains the distributed ledger; and

enabling the consensus network to compare the transaction hash to the information about the device that is stored on the distributed ledger.

14 . The method of claim 13 , wherein enabling the consensus network to compare the transaction hash to the information about the device that is stored on the distributed ledger includes:

enabling a smart contract executing on the consensus network to compare the transaction hash to the information about the device that is stored on the distributed ledger.

15 . The method of claim 14 , wherein the method further comprises:

enabling the smart contract to determine that the transaction hash is consistent with the information about the device that is stored on the distributed ledger; and

enabling the smart contract to authorize a new transaction using the device.

16 . The method of claim 15 , wherein the method further comprises:

storing, in memory included within the device, a new transaction hash that is based on the new transaction.

17 . The method of claim 14 , wherein the method further comprises:

enabling the smart contract to determine that the transaction hash is not consistent with the information about the device that is stored on the distributed ledger; and

enabling the smart contract to deny the new transaction.

18 . The method of claim 12 ,

wherein the device is in the form of a payment card.

19 . The method of claim 12 , wherein the device comprises a system on a chip having a secure enclave, and wherein storing the information about the transaction hash includes:

storing the information about the transaction hash in the secure enclave.

20 . A non-transitory computer-readable medium comprising instructions that, when executed, configure processing circuitry of a computing system to:

store, within a device in which precious metal is embedded, information about a transaction hash associated with the device, wherein the transaction hash is derived from prior transactions performed using the device;

detect an indication of a new transaction; and

compare the transaction hash to information about the device that is stored on a distributed ledger by communicating the transaction hash to a consensus network that maintains the distributed ledger.