The problem DarkLedger solves

DarkLedger is for doing high-value private financial deals without leaking information.

It’s useful anywhere people currently rely on:
• calls
• DMs
• spreadsheets
• manual approvals

because they don’t trust public blockchains or shared order books.

DarkLedger lets those same deals happen on a ledger, but with the same (or better) privacy as off-chain workflows.

Challenges I ran into

The biggest challenge was not functionality, but correct privacy behavior on Canton devnet.

Early on, things appeared to work:
• commands executed
• contracts were created
• UI showed data

But some flows were accidentally leaking visibility because:
• the wrong party was added as an observer
• a helper contract had broader stakeholders than intended
• a query was executed under the wrong participant context

On Canton, one extra observer = a real privacy bug, not just a UI issue.

How I fixed it
• I stopped trusting the UI and relied on devnet party-scoped queries
• I built an Inspector view that runs the same queries under different parties
• I added a “Privacy Challenge” outsider perspective to actively try to see private state

If a non-stakeholder could see anything, the model was wrong and had to be fixed at the Daml contract level.

Use of AI tools and agents

I used AI tools mainly to speed up development and reduce mistakes, not to replace core logic or decision making.

Tools used

I used Claude, CodeCodex, and Cursor during development.