Bitcoin Explorer (bx) is a command-line tool that offers a variety of commands for key management and transaction construction. It is part of the libbitcoin bitcoin library.
Usage: bx COMMAND [--help] Info: The bx commands are: address-decode address-embed address-encode address-validate base16-decode base16-encode base58-decode base58-encode base58check-decode base58check-encode base64-decode base64-encode bitcoin160 bitcoin256 btc-to-satoshi ec-add ec-add-secrets ec-multiply ec-multiply-secrets ec-new ec-to-address ec-to-public ec-to-wif fetch-balance fetch-header fetch-height fetch-history fetch-stealth fetch-tx fetch-tx-index hd-new hd-private hd-public hd-to-address hd-to-ec hd-to-public hd-to-wif help input-set input-sign input-validate message-sign message-validate mnemonic-decode mnemonic-encode ripemd160 satoshi-to-btc script-decode script-encode script-to-address seed send-tx send-tx-node send-tx-p2p settings sha160 sha256 sha512 stealth-decode stealth-encode stealth-public stealth-secret stealth-shared tx-decode tx-encode uri-decode uri-encode validate-tx watch-address wif-to-ec wif-to-public wrap-decode wrap-encode
For more information, see the Bitcoin Explorer homepage and Bitcoin Explorer user documentation.
Let’s look at some examples of using Bitcoin Explorer commands to experiment with keys and addresses.
Generate a random "seed" value using the seed command, which uses the operating system’s random number generator. Pass the seed to the ec-new command to generate a new private key. We save the standard output into the file private_key:
$ bx seed | bx ec-new > private_key $ cat private_key 73096ed11ab9f1db6135857958ece7d73ea7c30862145bcc4bbc7649075de474
Now, generate the public key from that private key using the ec-to-public command. We pass the private_key file into the standard input and save the standard output of the command into a new file public_key:
$ bx ec-to-public < private_key > public_key $ cat public_key 02fca46a6006a62dfdd2dbb2149359d0d97a04f430f12a7626dd409256c12be500
We can reformat the public_key as an address using the ec-to-address command. We pass the public_key into standard input:
$ bx ec-to-address < public_key 17re1S4Q8ZHyCP8Kw7xQad1Lr6XUzWUnkG
Keys generated in this manner produce a type-0 nondeterministic wallet. That means that each key is generated from an independent seed. Bitcoin Explorer commands can also generate keys deterministically, in accordance with BIP-32. In this case, a "master" key is created from a seed and then extended deterministically to produce a tree of subkeys, resulting in a type-2 deterministic wallet.
First, we use the seed and hd-new commands to generate a master key that will be used as the basis to derive a hierarchy of keys:
$ bx seed > seed $ cat seed eb68ee9f3df6bd4441a9feadec179ff1 $ bx hd-new < seed > master $ cat master xprv9s21ZrQH143K2BEhMYpNQoUvAgiEjArAVaZaCTgsaGe6LsAnwubeiTcDzd23mAoyizm9cApe51gNfLMkBqkYoWWMCRwzfuJk8RwF1SVEpAQ
We now use the hd-private command to generate a hardened "account" key and a sequence of two private keys within the account:
$ bx hd-private --hard < master > account $ cat account xprv9vkDLt81dTKjwHB8fsVB5QK8cGnzveChzSrtCfvu3aMWvQaThp59ueufuyQ8Qi3qpjk4aKsbmbfxwcgS8PYbgoR2NWHeLyvg4DhoEE68A1n $ bx hd-private --index 0 < account xprv9xHfb6w1vX9xgZyPNXVgAhPxSsEkeRcPHEUV5iJcVEsuUEACvR3NRY3fpGhcnBiDbvG4LgndirDsia1e9F3DWPkX7Tp1V1u97HKG1FJwUpU $ bx hd-private --index 1 < account xprv9xHfb6w1vX9xjc8XbN4GN86jzNAZ6xHEqYxzbLB4fzHFd6VqCLPGRZFsdjsuMVERadbgDbziCRJru9n6tzEWrASVpEdrZrFidt1RDfn4yA3
Next, we use the hd-public command to generate the corresponding sequence of two public keys:
$ bx hd-public --index 0 < account xpub6BH1zcTuktiFu43rUZ2gXqLgzu5F3tLEeTQ5t6iE3aQtM2VMTxMcyLN9fYHiGhGpQe9QQYmqL2eYPFJ3vezHz5wzaSW4FiGrseNDR4LKqTy $ bx hd-public --index 1 < account xpub6BH1zcTuktiFx6CzhPbGjG3UYQ13WR16CmtbPiagEKpEVtpyjshWyMaMV1cn7nUPUkgQHPVXJVqsrA8xWbGQDhohEcDFTEYMvYzwRD7Juf8
The public keys can also be derived from their corresponding private keys using the hd-to-public command:
$ bx hd-private --index 0 < account | bx hd-to-public xpub6BH1zcTuktiFu43rUZ2gXqLgzu5F3tLEeTQ5t6iE3aQtM2VMTxMcyLN9fYHiGhGpQe9QQYmqL2eYPFJ3vezHz5wzaSW4FiGrseNDR4LKqTy $ bx hd-private --index 1 < account | bx hd-to-public xpub6BH1zcTuktiFx6CzhPbGjG3UYQ13WR16CmtbPiagEKpEVtpyjshWyMaMV1cn7nUPUkgQHPVXJVqsrA8xWbGQDhohEcDFTEYMvYzwRD7Juf8
We can generate a practically limitless number of keys in a deterministic chain, all derived from a single seed. This technique is used in many wallet applications to generate keys that can be backed up and restored with a single seed value. This is easier than having to back up the wallet with all its randomly generated keys every time a new key is created.
The seed can be encoded using the mnemonic-encode command:
$ bx hd-mnemonic < seed > words adore repeat vision worst especially veil inch woman cast recall dwell appreciate
The seed can then be decoded using the mnemonic-decode command:
$ bx mnemonic-decode < words eb68ee9f3df6bd4441a9feadec179ff1
Mnemonic encoding can make the seed easier to record and even remember.