Trezor Custom Mnemonic

Question

How do I go about using words I pick in a trezor seed? I only want words that I select and in an order I select.

I'm not worried about this being a less secure way to generate a seed. I will be doing all this off line with a disposable computer if necessary. I want to use a custom word list in conjunction with some custom math that with generate the correct order of my seed.

I have yet to find a way to do this with my trezor. I personally think that my backup seeds are safer in my head then on a piece of paper.

I tried generating public/private keys with a custom mnemonic with custom words. Didn't work.

I tried generating public/private keys with a custom mnemonic with a word list generated from myTrezor.com (A-Z, excluding X, approximately 10 words to choose from per letter)[I did this by typing in each letter and copying the choices from the drop down] Didn't work. [Error: Action was interrupted Invalid mnemonic, are words in correct order?]

Shouldn't a valid public/private key pair be generated regardless of the words I pick and the order I put them in?

Answer 1

Trezor implements the standard described in BIP 0039, which generates a menemonic from a predefined list of words. From this mnemonic the seed is generated. There is no way to choose your own words or word order for the mnemonic with Trezor.

Answer 2

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.

Answer 3

If you simply need to seed your trezor with your own mnemonic seed then here is a simple walkthrough on how to do it:

https://doc.satoshilabs.com/trezor-user/recovery.html