Short version:

Decentralized group of oracles publish PGP public keys, followed after a delay by the corresponding private keys. Bitcoiners can get some physical security by time locking keys needed to spend utxos by encrypting the spend keys to a PGP public key published by the oracle. In order to…

Recent public comments about hardware wallet supply chain attacks have me re-thinking my setup. Here are precautions I follow when using ColdCard in a single-sig setup.

  1. Only buy ColdCard from the manufacturer, and verify the bag serial number with the device serial number.
  2. Do not trust ColdCard to derive the…

When miners create two Bitcoin blocks at the same height, what determines which sub-chain will come to dominate the other? Which sub-chain will be more economically important, used by more people, and have a higher price?

Usually the answer is Hashrate

Usually, the sub-chain that accumulates work fastest will become…

A Physical Bitcoin Bearer Bond Design

Aaaaand it’s broken:

The design below is seriously flawed, since Alice always has the private keys — and once Bob spends the coins he reveals the preimage. This front-run attack plagues any lock that does not use an asymmetric key. ¯\_(ツ)_/¯

Description:

Opchip is an idea for a…

Description:

Sealed Wallet is a hardware device that enables transferring control of Bitcoin by exchanging a physical object. It is a USB device that can do the following:

1. Generate a private key on the device
2. Sign transactions using the private key
3. Refuse to double-spend outputs
4. Prevent the private key from…

Ethan Scruples

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