Zero-knowledge packed binary data format

[stenreijers]

Following section 5.4 on Data Schemas the following example is shown:

"credentialSchema": {
 "id": "https://example.org/examples/degree.zkp",
 "type": "ZkpExampleSchema2018"
}

According to the specification this "credentialSchema" is pointing to a zero-knowledge packed binary data format that is capable of transforming the input data into a format, which can then be used by a [verifier](https://www.w3.org/TR/vc-data-model/#dfn-verifier) to determine if the proof provided with the [verifiable credential](https://www.w3.org/TR/vc-data-model/#dfn-verifiable-credentials) is valid.

This sentence is not clear to me, what is a "zero-knowledge packed binary data format"? and how does this work? Can somebody here give an example of such a file and specify how this works exactly? Perhaps the specification can include references on this topic, because it seems highly relevant for use-cases where a ZKP is included in derived VCs.

[dlongley]

Possible duplicate / related to #890.

[iherman]

The issue was discussed in a meeting on 2023-04-04

• no resolutions were taken

View the transcript

1.7. Zero-knowledge packed binary data format (issue vc-data-model#949)

See github issue vc-data-model#949.

Kristina Yasuda: About ZK binary data format. No response on the issue..

Brent Zundel: I'll take this one.

Kristina Yasuda: Thanks Brent..

Brent Zundel: I'll try to answer this question, and that the answer to the question will not be found in the core data model..

[brentzundel]

The highlighted sentence doesn't really describe what happens in ZKP signatures. it would probably be better to change the sentence to be more general:

In the example above, the issuer is specifying a credentialSchema pointing to a means of transforming the input data into a format which can then be used by a verifier to determine if the proof provided with the verifiable credential is valid.