kagikai / Multisigbearer is on Nostr

Kagikai.app working on bitcoin mainnet - decentralized - non-custodial payments with no fee to send peer to peer, really fast. No central server, or channels needed.

Last Notes

2026-05-06 00:09:17 UTC

New video dropping soon..
Receive fast bitcoin payments
non-custodial
secure enclave
cryptographic receipt
no central server
no liquidity channel
no copy paste keys and complicated configs
online or offline
install the app and go
it. just. works.
https://blossom.primal.net/e7aa4d5668a9d936254389fab2b80bc5864ae53931ac2704d4dc1af64ad54338.png

2026-04-04 17:42:03 UTC

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It assumes nothing of the sort.
This is fully operational now, on bitcoin and is a mechanism for sending bitcoin peer to peer - without any additional infrastructure other than your phone - with instant settlement and custodianship, no waiting for10 minute confirmations.
Think lightning network, but you don't need a node, or a payment channel or a stable internet connection. It even works offline through encrypted QR code payload transfer.
The bitcoin network is the custodial trust.

2026-04-04 15:56:10 UTC

Not your key not your coins.
We've been told to guard our keys with our lives..
But what if we... DELETED keys to stay secure?
Multisig Bearer Instruments uses key threshold inversion.
The issuer deletes their keys which they never actually got to view with cryptographic proof they 100% did.
The bearer is the only one with 2 of 3 who can spend. Ever.
#bitcoin #sovereign #cryptogtaphy

2026-04-04 09:40:31 UTC

Sovereign Bearer Banknotes on Bitcoin
https://blossom.primal.net/cc5e9bb911178e9204c864a95d29ae6bd5cfee9775adf174cf375a1d84b5a9d3.png

2026-04-04 01:25:16 UTC

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welp, just replied to a bot, anyways..

2026-04-04 01:24:14 UTC

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Making sure of sovereign custody and no double spend.
Making sure the keys are deleted and zeroed from memory to ensure that when the keys are sent there's no way to retrieve them from the device and not relying on code or honesty of the sender.
The payload construction and encryption of it was very difficult also, but happy with current state.

2026-04-04 01:05:35 UTC

I'm not great at writing or low level coding - there may be errors & I am open to and invite any feedback.
I have a working signet POC app. It's not marketing or vaporware - I'm a long time bitcoiner and have been thinking of the solution to fast bitcoin payments with no infrastructure and low barrier to entry for everyone.
If you can use a banking app, you can use this.
I would like to have cryptographic experts review the code, and I will make that available. There is proof it works on chain and I have been as rigorous as I can with security and attack vectors.
I will post a demo video which will make it clear in the next week - just needs a little UI/UX work.
#bitcoin #multisig #payments #nostr

2026-04-04 00:49:13 UTC

Utreexod looks nice.
200 GB is better than 1Tb
For mobile devices it's still a bit of a lift.
Part of my paper deals with bounded utxo set for a reset at the 17 year mark where you don't have to verify past transactions only present and future transactions since protocol launch.
Very doable on phones today and for the next many years.

2026-04-03 23:39:31 UTC

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@nprofile…0m5k

2026-04-03 21:12:46 UTC

MBI - a simple explainer
A Bitcoin 2-of-3 multisig instrument is created inside a secure enclave.
The issuers key is deleted immediately. Now there are 2 keys left and you only need 2 to spend and those 2 keys were issued to the user.
The instrument is funded while both keys stay inside the enclave. Only holder can spend, hold, or transfer it. The issuer is locked out.
Because the keys are encrypted in transit and never leave the enclave in the open, the instrument can be sent over any channel without exposing anything spendable.
To transfer, the two keys are packed into an encrypted payload addressed to the recipient's public key. The recipient's enclave decrypts it. At no point do the raw keys exist outside an enclave.
That payload can go over a relay, a QR code, NFC, or any other transport. The security does not depend on the channel.
Once the recipient confirms receipt, the sender deletes their copy of the keys. The receipt is a signed acknowledgment from the recipient's enclave, proving the payload was received and decrypted using QR codes p2p or Nostr when online. Without that signature the sender holds on to the keys. Once they have it, they must delete them. Holding on means double spend risk against yourself.
Key deletion is what makes the transfer final. There is no server to update. No ledger to write. The instrument simply no longer exists in the sender's enclave.
When the holder wants to settle, they sweep. Both keys sign a transaction inside the enclave and broadcast it to the Bitcoin network. The funds move to a regular address the user controls.
The instrument is spent and destroyed.
The sweep can happen immediately or months later. Until then the instrument circulates off-chain, passing between enclaves, with no timechain footprint. Every hop is free and instant. Only the final sweep costs a fee.
No changes are needed to Bitcoin, this works under current consensus rules.
tldr; No infrastructure (nodes, channels or servers) other than a phone to send bitcoin p2p in person or over the web with zero fees (until redemption to the timechain), really really fast.

2026-04-03 16:33:34 UTC

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@fiatjaf the Nostr receipt mechanism in MBI uses kind=1 with #p routing for cryptographic proof of key transfer between sender and receiver. Chose kind=1 specifically to avoid relay fingerprinting and silent rejection on custom event kinds. Relay selection is a configurable deployment parameter, production deployments would use dedicated or paid relays rather than public infrastructure. Curious if you see any relay behaviours that would undermine this, and whether the network impact framing looks right to you.

2026-04-03 00:33:57 UTC

17 Years since block zero ⛓️
Bitcoin: A Peer-to-Peer Electronic Cash System
Day zero for Multisig Digital Bearer Instruments: Trustless Digital Cash
A complementary protocol for peer to peer cash, no infrastructure, no BIP request - self sovereign key transfer where the issuer has no control after creation - on the Bitcoin network under current consensus.
The bearer holds the spending threshold, the issuer holds a sub-threshold key deleted before funding.
Transfer is keys handover, no fees, no network required..
Online cryptographic proof of transfer and key deletion over Nostr.
Offline cryptographic proof through encrypted payload exchange via QR.
https://multisigbearer.org
https://zenodo.org/records/19382670