Encrypted on-chain messaging via the privacy pool

What this enables

• →Encrypted on-chain mail between any two privacy-pool participants - addresses never appear on-chain, messages decrypt only on the recipient's device.
• →Payment memos - attach a message to a private transfer in the same transaction. The first credible "remittance with note" primitive on a public chain.
• →Escrow negotiation - parties coordinate terms privately before executing a transfer, without ever leaking the relationship to observers.
• →A reusable substrate for any application that needs metadata-resistant messaging - anonymous tips, dissident comms, professional escrow.

What you build

A helper contract callable via InvokeExternal that appends encrypted message payloads to per-channel storage. An off-chain discovery indexer that returns decrypted messages for a given viewing key. SDK methods (sendMessage, discoverMessages) that reuse the same ECDH channel-key derivation the pool already uses for note encryption.

Why it ships

The privacy pool already gives you everything hard about secure messaging: key agreement via ECDH, encrypted persistent channels, sender anonymity via InvokeExternal (the pool is msg.sender, not the user). The work here is the helper contract, the indexer, and an SDK extension. No protocol changes required.

Hidden vs visible

| Element | Hidden | Visible | | --- | --- | --- | | Sender identity | Yes - pool is the msg.sender | | | Recipient identity | Yes - only resolvable via the recipient's viewing key | | | Message content | Yes - encrypted with the channel key | | | That a message was sent | Partially - an observer sees a pool transaction occurred | Block timestamp |