Look at the hardware brain wallet tcsh script for how to configure Trezor offline. This script uses BIP 39 mnemonic words to restore trezor devices. This short script can be shortened further to accomplish what you want. Additionally, the example software BIP 39 mapped brain wallet demonstrates how to measure the entropy associated with a BIP 39 root seed. High entropy is a requirement for establishing your own low risk BIP 39 words.
Here is the secret sauce for using libbitcoin's bitcoin-explorer (bx) command line interface offline without a password.
Here is how to use bx
to mimic what a Trezor does to generate an address for m/44'/0'/0'/0/0 to mimic configured Trezor behaviors:
% echo "core leaf knee fashion gap decade radar double bulk fruit pitch either club citizen inspire gravity clinic build decade latin alter craft cherry glance" | bx mnemonic-to-seed | bx hd-new -v 76066276 | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-public -i 0 | bx hd-public -i 0 | bx hd-to-ec | bx ec-to-address -v 0
12VwB8c4NRHPaxuaLWXRWE1Rf3jJxa4FvD
For the corresponding uncompressed private key:
% echo "core leaf knee fashion gap decade radar double bulk fruit pitch either club citizen inspire gravity clinic build decade latin alter craft cherry glance" | bx mnemonic-to-seed | bx hd-new -v 76066276 | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-private -i 0 | bx hd-private -i 0 | bx hd-to-ec | bx base58check-encode -v 128
5JvjtTwgkEx8urCTenmusab5PkV1SjniTmgGKvPqx7xHmSZPgGz
And for the corresponding compressed private key:
% echo "core leaf knee fashion gap decade radar double bulk fruit pitch either club citizen inspire gravity clinic build decade latin alter craft cherry glance" | bx mnemonic-to-seed | bx hd-new -v 76066276 | bx hd-private -d -i 44 | bx hd-private -d -i 0 | bx hd-private -d -i 0 | bx hd-private -i 0 | bx hd-private -i 0 | bx hd-to-ec | sed 's/$/01/' | bx base58check-encode -v 128
L28CJ9vNRraMvG9ado3ENFFQPQvcxbrn1ACJeWfq4Hh2zwXeQqDt
Trezor and Keepkey hardware wallets are using compressed keys to prevent uncompressed public keys from bloating Bitcoin's blockchain.
For Bitcoin-based altcoins, use m/44'/SLIP_44_Table'/account'/(0 or 1)/n in conjunction with version (-v) selected from BIP 44 Altcoin Mapping Table to reconstitute addresses and private keys. Computation of addresses using base58check-encode will use version values from the mainnet version_p2pkh column, similarly computation of private keys using base58check-encode must use the mainnet version_WIF column of the BIP 44 Altcoin Mapping Table.
FYSA - A single Trezor device can support multiple ASCII passwords to support a plausible deniability capability. However, only one password can be active at a time for a Trezor application session. The bx mnemonic-to-seed sub-command also accepts passwords.