By default, all transactions are signed seamlessly on the server, using your encrypted account private keys. This makes placing-, accepting- and finalising orders as simple as clicking on a button. If, however, you prefer to sign your transactions manually, you may enable manual multisig in your account settings.
When you add or change your public key, you will be asked to verify ownership by signing a message. Console commands are given for Bitcoin Core and Electrum. Having imported the relevant private key, you simply copy-paste the command into the console, press enter and the client will compute a signature. Paste this signature into the box on Alpaca and click 'Submit'.
Note: for BIP32, you first have to derive and import the correct child private key. The derivation path is given in the upper right corner of the signature window.
With manual multisig enabled, you will be prompted to manually sign raw transactions when you place-, accept and finalize orders. The process is similar to verifying your public key from earlier:
Ensure that the raw transaction has correct outputs. If you notice any suspect recipients, please notify a moderator or admin as soon as possible.
Console commands have been pre-generated for Bitcoin Core and Electrum. These can be entered in the console to easily sign the transaction. In Bitcoin-Qt, the console window is found under Help→Debug window→Console. If you wallet is locked, you will need to enter walletpassphrase yourpassphrase 120 to unlock the wallet.
If you haven't already, import the relevant private key into your bitcoin client. In Electrum: Wallet→Private keys→Import. In Bitcoin-Qt: Enter into console: importprivkey "5yourveryveryveryverylongprivatekeystring"
Copy-paste the command into console and press enter. Note: the current version of Electrum is not able to sign 3-4 multisig transactions, so you will need to use Bitcoin core or other software to sign these.
If the transaction was valid, the console will output a signed raw transaction. Look for 'hex' followed by a large block of text. This is the signed transaction.
Copy-paste the signed transaction into the prompt on the site
Click 'Sign'
If everything went well, you should be redirected to the next step. If not, you will be made aware of any errors. Be aware that you may sometimes have to sign multiple transactions in a row.
Did you accidentally deposit more than required on an order?
All confirmed excess funds gets sent back to your return address once the order is placed.
Did you deposit after placing the order?
All funds in deposit addresses can be recovered manually using your account's encrypted private keys.