Signing machine

[oxf71]

flow

1. Enter the private key when the signature machine starts. need to enter the private key every time the signature machine starts
2. The signature machine periodically obtains the data hash to be signed from the b2-node
3. The hash of the signed data is signed and sent to b2-node
4. After receiving a certain amount of signature data, the b2-node withdraw can send the transaction to the btc network