Certificate Properties

Terms, Definitions & Properties - ERC1888

Definitions

issuer: is another smart contract, which issues a transferable certificate.

certificate: A certificate is an information an issuer has about the certificate (on top of the token balance). This contains the following:

topic: uint256 number which represents the topic of the certificate. (e.g. 1: origin-of-electricity, 2: electricity-with-origin)
issuer: The issuer is a contract address itself, at which the claim can be verified using the call validityData.
validityData: validity call data to issuer. Contains the signature of the function to verify the certificate as well as encoded parameters of the function to ultimately check the validity of the certificate.
issuenceData: The hash of the certificate data, sitting in another location, a bit-mask, or actual data based on the certificate topic.

Certificate Properties

ERC-1888 Data Structure

struct Certificate {
  int256 topic;
  address issuer;
  bytes validityData;
  bytes data;
  }

Example inputs: Green Hydrogen Producer in Australia

Topic

The topic is an integer number that describes the type of certificate that is issued. Topics are a standardized way of defining the properties of a certificate. Every certificate with the same topic should have the same standardized data structure.

Issuer: The issuer data field contains the blockchain address of the issuer that created this certificate. Generally, there should only be a small number of local issuers (mostly even only one) that are authorized to issue certificates in accordance with regulation. The address of these issuers should be publicly known and therefore act as a proof of authenticity on certificates.

Certificates are created and issued through the REC Registry —an online trading platform managed by the Clean Energy Regulator.

Validity Data: Validity Data is a callback function that returns either true or false based on predefined criteria. It is used to check if operations like claiming or transferring a certificate are valid. This functionality is needed because the issuer reserves the right to suspend any non-claimed certificate at any time.

Data: There is a significant amount of data that is recorded in additional to the items descripted above. Some of the mentioned previously is device id and the time of generation. The data field can host any arbitrary set of information. Every certificate with the same topic, for example, "Hydrogen Gas", must have its data structured in the same way to allow for easy interaction. IPHE's compliance & standards documentation is discussed in detail in "Methodology". It is currently the globally accepted framework for hydrogen emission reporting practices. As such, Australia's REC Registry will issue a certificate in response to a certification request, if the green hydrogen producer provides evidence that satisfies the below categories (summarised for simplicity).