I've been building denominated Bitcoin bearer instruments using an inverted 2-of-3 multisig threshold. The bearer holds both spending keys, the issuer holds one sub-threshold key and is mathematically locked out from the moment of issuance. No custodian, no federation, no mint operator, no server shutdown who can rug.

The aim is practical peer-to-peer electronic cash on Bitcoin mainnet. Send someone the utxo, they own it, with no coordinator involved.

Mainnet transaction proofs are already live at kagikai.app, including an early merchant demo.

Today:

• Self-sovereign issuance - private keys generated and stored inside hardware security enclaves (Android StrongBox / iOS Secure Enclave), never exposed to the app layer, never leaving the device
• Non-custodial by construction - the 2-of-3 threshold means the issuer's single key is mathematically insufficient to spend, from the instant the note is created
• Decentralized transfers - no servers, channels, liquidity pools, or coordinators required. Notes move directly between enclaves, peer-to-peer
• Zero fees on transfers - no network costs until final on-chain settlement
• Sub-5s settlement when sweeping to mainnet
• Nostr receipts for transfer verification
• Fully offline capable - transfers work without internet via local UTXO cache
• Headless merchant server option for point-of-sale integration

Currently in active development: cryptographic key deletion attestation inside the enclave. This gives the receiver hardware-attested proof of possession before the sender's copy is irreversibly destroyed, closing the last meaningful gap toward true bearer behavior without trusting app logic.

The enclave is not just a keystore. It is the transport layer. Keys never exist in userspace. They are born inside tamper-resistant hardware, transferred between enclaves, and deleted with attestation. The entire custody model runs below the OS.

Happy to chat about the multisig threshold model, similarities to existing proposals in development or anything else.