Block Qualified Test Proof

In order to obtain a test credential, the user must first provide a proof that shows they have necessary knowledge to obtain it.

Generating a Proof

You can use the @bq-core/lib library to generate such proofs, passing the following parameters to the generateTestProof function:

• identity: the Semaphore identity of the user generating the proof.

• testAnswers: composed of:

  • multipleChoiceAnswers: list containing the user's answers to the multiple choice component.

  • openAnswers: list containing the user's answers to the open answers component.

• testVariables: the parameters that define the test, these being the minimumGrade, multipleChoiceWeight, nQuestions, multipleChoiceRoot, openAnswersHashesRoot, and openAnswersHashes; as described in Block Qualified Tests.

• identityGroup: the group to which the user will be added, this logic being enforced by the smart contract:

  • If the grade obtained is above the specified minimumGrade for this test, this will be the credentials group.

  • Otherwise, minimumGrade must be set to 0 so that the proof does not revert, and this will be the no-credentials group.

• gradeGroup: the Semaphore-like group containing the grade commitments of all users that attempted to obtain the credential.

• testPassed: boolean value indicating whether the test was passed or not, which is later verified at the smart contract level.

• snarkArtifacts: the zkey and wasm trusted setup files.

• testId: the ID for this test, used to compute the value for the empty leaf when Merkle proofs are provided instead of groups.

When providing a group to this function, an empty leaf is added in order to generate the corresponding Merkle proofs.

If the proof is later accepted by the smart contract and the corresponding on-chain groups get updated, developers should use the updateMember function to update their off-chain groups. Using the addMember function instead would create a new leaf after the empty leaf that was added before.

Verifying a Proof Off-Chain

You can use the @bq-core/lib library to verify a generated proof via the verifyTestProof function:

import { verifyTestProof } from "@bq-core/lib"

await verifyTestProof(testProof) // true or false.

Which returns a promise that resolves to true or false.