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Bearer

Try Bearer in 60 seconds

A parent sends their child Bitcoin, sealed.

The child can check it's untouched, make it theirs alone, and open it when they're ready. Nobody who held it before can take it back. Six steps, each on NEAR testnet.

  1. 1

    See a sealed vault with Bitcoin inside

    Live

    A parent filled vault No. 0009, “1st Son College Fund”, with 300,000 testnet sats and 0.5 SOL. Its page reads the chain as you look: sealed, 0 withdrawal signatures ever requested, and the coins at its own Bitcoin and Solana addresses.

    Open vault No. 0009
  2. 2

    Receive one as a link

    Hands-on

    A Bearer link holds its own small vault with real testnet coins. Open it and you hold the vault, with no wallet. Each link is a key, so they go out one per person and are never posted publicly. Got one? Open it from the message it came in.

    Open a link
  3. 3

    Secure it first

    On testnet

    Whoever sent the link still has a copy. The link page's first step moves the vault to a new private link or your NEAR account, and every copy of the old link is left empty. Vault No. 0010 went through three links like this; each earlier one then read “This link is empty”.

    Vault No. 0010's custody
  4. 4

    Same coins, new holder

    On testnet

    Handing a vault over moves nothing on Bitcoin. Vault No. 0006 held 684,666 sats when it changed hands in one NEAR transaction; that coin stayed at its address until the new holder withdrew it.

    The handoverThe withdrawal, on Bitcoin
  5. 5

    The previous owner is locked out

    On testnet

    A former owner asking for a withdrawal, or trying to break the seal, is refused by the contract (ERR_NOT_OWNER), and nothing reaches the signer. These were sent to the locked contract as real transactions; the attack lab re-reads each one from NEAR when you press Check.

    The attack lab
  6. 6

    Open it, and see the withdrawal

    On testnet

    Breaking the seal is permanent: an opened vault can never change hands again. Vault No. 0012 was opened from its link, with no wallet, and its Bitcoin withdrawal is byte for byte the transaction the contract signed.

    Vault No. 0012Its Bitcoin withdrawal

Check it all without trusting this page

pnpm verify in the repository checks every claim here, and the README's, against the public chains: read-only, no keys. The proof page checks the contract's lock and code from your browser.

The proof page

Testnet coins have no value. Not audited.