Allow selective disclosure with ops other than $eq.

[nedgar]

The current support for selective disclosure is indicated by query {fieldName: {}}, which implicitly assumes the operator is $eq, with value being the current value in credential.

If selective disclosure was purely an option, and the other operators were allowed, it would support a challenge like “prove you’re an adult and disclose your age only if so”, e.g. so no PII about minors would be collected.

Discussed with @OBrezhniev in Slack, who said:

Interesting use case. Should be possible to implement without changes to circuits.

[ottomorac]

Interesting. I will add to our confluence requirements tracking. Would you agree that we call this "conditional selective disclosure"? @nedgar ?

[nedgar]

@otto-mora Hm, I'm not sure. I guess the naming could distinguish between the "pure" selective disclosure case, where the original value is unknown and no comparison is given (so holder generates proof using $eq on the current value) vs one where a comparison is given (as suggested above). It's not that different from using $noop operator, or $neq with some impossible value, or $nin with an empty set. Maybe it should just be made an option for selective disclosure, and if no condition is given it defaults to $eq with current value. If it's important to distinguish between these two cases, then "selective disclosure" and "conditional selective disclosure" make sense.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[nedgar]

.

[ottomorac]

@nedgar let me look to see how we can prevent this stuff from being marked as stale. I believe there is a setting to add a special label. @mmilenkovic can you please try to see how we can add this setting https://github.com/actions/stale#exempt-issue-labels. Perhaps issues labeled as "bug", and "enhancement" can be exempt from the Github Actions bot?

[Kolezhniuk]

@demonsh