This module does not provide the following functionality:
- Programmatic issuance/revocation of document on the Ethereum blockchain
- Install Node.js
- Install the library:
npm install @govtechsg/oa-verify
Verifying a document
A verification happens on a wrapped document, and it consists of answering to some questions:
- Has the document been tampered with ?
- Is the issuance state of the document valid ?
- Is the document issuer identity valid ? (see identity proof)
Before starting to play with the library, create a file
document.json having the following content:
This is a wrapped document created using OpenAttestation Wrapper SDK.
Let's make sure the document is valid:
In some cases, you will need to perform more verification on a document than the one provided by default. Fortunately the library is configurable in a way you can create your own verification methods and distribute your verifier.
isValid function will execute over fragments and determine if the fragments produced a valid result. By default the function will return true if a document fulfill the following conditions:
- The document has NOT been tampered, AND
- The document has been issued, AND
- The document as NOT been revoked, AND
- The issuer identity is valid.
However in some conditions, the result of the function might not be useful: Why is the document not valid ? Is it because it has been tampered ? Or maybe the issuer identity is invalid ?
The function allow to specify as a second parameters the list of types on which to perform the checks. Let's try to run the verifier on
mainnet network :
Let's try to understand the different results:
isValid(fragments, ["DOCUMENT_INTEGRITY"])returns true because the integrity of the document is not dependant on the network it has been published to.
isValid(fragments, ["DOCUMENT_STATUS"])returns false because the document has not been published on Ethereum main network.
isValid(fragments, ["DOCUMENT_STATUS"])returns false because there is no DNS-TXT record associated with the Ethereum main network's document store.
isValid(fragments)returns false because at least one of the above returns false.
Listening to individual verification method
verify function has an option to listen to individual verification methods. It might be useful if you want for instance to provide individual loader on your UI.