# Selective disclosure as a compliance primitive

> Selective disclosure as a compliance primitive: Bilateral disclosure versus publishing to everyone. Region: Global.

Part of the Soda Labs Privacy Hub regulation map, which reads the instruments
themselves rather than summarising the summaries: https://www.sodalabs.xyz/privacy-hub/regulation

## Key facts

- Entry type: Where privacy tech meets the rulebook
- Region: Global
- Subject: Bilateral disclosure versus publishing to everyone
- Tags: viewing keys, selective disclosure, auditor access, no regulator endorsement yet
- Canonical page: https://www.sodalabs.xyz/privacy-hub/regulation/why-viewing-keys

## What it actually says

Supervisory access, external audit and suspicious activity reporting are all bilateral disclosures to a named party under a legal duty. Public-ledger transparency is something else entirely: universal, unauthorised disclosure to everyone, permanently. No other part of the financial system is asked for the second in order to satisfy the first. Viewing keys are the oldest worked example, letting a holder share visibility of shielded activity without surrendering the ability to spend, and they are already used for exchange deposit detection and custodian-to-auditor disclosure. Threshold decryption generalises this to a quorum. Two honest caveats. We found no regulator that has endorsed the pattern in guidance, so this is an argument from structure rather than from authority. And viewing keys are blunt: per address, retrospective and prospective at once, with no revocation once shared.

## The instruments that matter

- **Zcash viewing keys**: derived from the spending key; an incoming viewing key detects deposits, a full viewing key exposes value, memo and target address without exposing the spend key
- **Threshold and auditor keys**: generalise the same idea to a quorum, removing the single point of failure a lone disclosure key creates

## Sources

- [Electric Coin Company on viewing keys](https://electriccoin.co/blog/explaining-viewing-keys-2/)

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- [Erasure against an append-only ledger](https://www.sodalabs.xyz/privacy-hub/regulation/why-erasure): The one collision with no clean answer yet
- [Proving where funds did not come from](https://www.sodalabs.xyz/privacy-hub/regulation/why-privacy-pools): Association sets, and the Tornado Cash aftermath
- [Sanctions screening on a confidential ledger](https://www.sodalabs.xyz/privacy-hub/regulation/why-sanctions-screening): The genuinely open problem
- [The travel rule binds institutions, not ledgers](https://www.sodalabs.xyz/privacy-hub/regulation/why-travel-rule): The rule everyone assumes ends on-chain confidentiality