The term “parcel” is used refer to any uniquely tracked item. Typically, a parcel will consist of a single gold bar packaged in a tamper evident GramChain® bag. If a bar has a serial number, the bar’s mass, brand and serial number are used as a unique identifier and it is placed in a type A bag.
For example, the parcel ID of a single Metalor bar would be identified using the bar serial number: 1kg METALOR bar - 1234567890
For bars or coins that do not have serial numbers or in the case that multiple bars are tracked together as a single parcel, they will be placed in a type Bx GramChain® bag which has its own serial number that can be used for tracking. Multi-item parcels must always contain identical items of the same brand, mass, metal and purity.
For example, a parcel ID containing five 100 gram Valcambi Bars in a type Bx bag with serial #B0002345 would be identified using the bag serial number as: 5x 100g VALCAMBI bars - B0002345
The Parcel ID is used by vaults and the GramChain® explorer to view and identify parcels. GramChain® parcels are also tracked by a GramChain® RFID chip and can be redundantly identified by either their Parcel ID or RFID.
Photos are important because bullion bars have key details etched into the bar itself and comparing the photo with the scanned details provides an additional method to verify parcel data.
GramChain® requires minimum quality standards for the parcel photo taken at the vault. GramChain® photos must clearly show the following details:
- The bar (type A) or bag (type Bx) serial number
- The GramChain® RFID tag
- For bags containing multiple items, the number of items must be clearly visible
- The brand, metal, mass and purity of at least one item
- White label bars must have a visible refinery hallmark
When a parcel photo is taken by the GramChain® scanner, a QR code is immediately added to the image which links to the public parcel data and the image’s hash is generated. The image hash is in turn hashed together with the salted hash of the scanner’s user ID, location, time and bar characteristics. The resulting event hash is stored on the Ethereum blockchain.
Both the raw data, photo and the hashes are public data. Furthermore, each new event contains a hash of the previous event. This system ensures that neither CACHE nor GramChain® can manipulate event data as any manipulation of prior event data will invalidate all subsequent event data.
In the bullion industry, the provenance of bars, sometimes also referred to as the chain of integrity, is an important concept because provenance controls offer protection against both AML/CFT risks as well as fake bullion. CACHE works only with reputable liquidity and storage providers that follow standard industry best practices and can clearly document the source of their bullion.
A chain of integrity requires that once bullion has been redeemed by a private individual and removed from the tamper evident bag, it cannot re-enter the system without purity testing and AML/CFT checks. Re-entering into the chain of integrity can occur either by sending the bullion back to a refinery for recasting or by testing the bullion. In both cases AML/CFT screening is performed first.
Deposit of branded gold from outside GramChain’s chain of integrity requires two steps:
- Registration and verification of a CACHE Gold account.
- The bullion must be delivered to a vault with approved testing facilities (e.g. DUX) or to an approved refinery for recasting.
While no system is infallible, CACHE is designed to meet or exceed the AML/CFT requirements of the Singapore Precious Stones and Precious Metals (Prevention of Money Laundering and Terrorism Financing) Act 2019.