The Seedpicker guide for creating your own seed phrase

This guide aims to educate the reader in a learning-by-doing fashion. However, it does not make any guarantees or promises, and does not take any responsibility for what anyone does with this material.

What you need

There are two ways of generating the seed phrase. One that uses a a lookup table and one that uses a webpage. If you opt for the Lookup Table-version you’ll also need:

Part 1: Generation of 23 random words

Human beings are really bad at randomness! When randomness is important, you should never rely on something that comes from a human brain! Modern computers are getting better at creating randomness, but it is still difficult to make computerized randomness in a way that is transparent to us humans. In other words, it is hard to convince humans that a random number has been created in a truly random fashion. This is the reason most public lotteries use physical and transparent lotto machines instead of using computerized randomness; It is crucial to convince the audience that the randomness is real and not manipulated in any way.

You can create the seed phrase manually using a lookup table in one of two ways. The Lookup Table or The Dice page.

1.1 Lookup Table

This method uses a combination of raffle tickets and a six-sided playing die to create very good natural and transparent randomness.

This is how you do it:

When finished, you should have a sheet of paper with 23 secret words, generated with a very high degree of randomness. Randomness that you yourself have witnessed. Don’t ever let anybody see what you have written on your Seed Form!

1.2 Dice Rolling page

This method is an automated version of the lookup table that uses one die and the Dice Rolling page that has the lookup table built-in. If you don’t want to bother with cutting raffle tickets this method is for you. The downside is that there’s a lot of dice rolling. If you’re interested in the math behind this method see the last paragraph in this section.

This is how you do it:

This bears repeating: Don’t ever let anybody see your seed phrase!

If you’re not interested in the math behind this metod you can go to Part 2.

1.3 Explanation

The BIP39 dictionary consists of 2048 words. 2048 can be represented in binary with 11 bits. 11^2 = 2048. If you roll a die, treat 1-3 as a 0, 4-6 as a 1 and repeat this eleven times then we get a binary number that corresponds to a word in the word list.

Instead of using a die you could use a coin and use heads and tails to generate your 11 bits.

Part 2: Calculating the 24th word

The last word of a 24 word seed is a checksum word, calculated using the other 23 words as input. Unfortunately, we need to use a computer for this step. Since we need to enter our super secret 23 words into a computer, it must be a super secure computer! It must be offline and we must make sure all the secret data is completely discarded after shutdown. Follow the steps below to achieve this!

2a: Prepare hardware and software

seedpicker.net/calculator/last-word.html

This is the SeedPicker last word calculator. Let the page load but DO NOT ENTER ANYTHING IN THE FORM AT THIS POINT!

Tip for advanced users: Open a second tab and navigate to iancoleman.io/bip39, but DO NOT ENTER ANYTHING AT THIS POINT! Having this page pre-loaded will later enable you to double-check the validity of the generated seed phrase, right before you shut down the computer.

Note that the code on the web page(s) downloaded in the previous step does not need to be trusted! Why? Because the 23 words that we created and wrote on paper in the previous step cannot be changed by any software!

However, we do have to make sure that the secret information will not leak to the outside world, or to future users of the same computer._ This is achieved by disabling all communication and by shutting the computer off when we are done. This is covered below.

2b: Disable all communication

The secure computer is now fully configured and the next step is to go completely offline:

2c: Perform the calculation

Go back to Firefox and the SeedPicker last word calculator. Following the instructions on the page, enter your 23 words into the field and press the button.

Use your pen to type the resulting 24th word into the designated cell of the Seed Form.

Shut down the computer. Make sure it is completely turned off.

Summary

You have now generated a valid BIP39 seed phrase and the only existing record of it is the Seed Form. Keep it really secret. You may want to make copies and put in different locations. If you create copies, do it manually. Don’t use a copier, camera or any form of computer.

This guide does not cover how to store your seed phrase securely, so do your research well.

If you intend to use the seed phrase with a hardware wallet, it is recommended to use the passphrase feature (sometimes called the 25th word) and keep the two phrases separated.

Comments or suggestions?

Visit github.com/merland/seedpicker or send an email to seedpicker@megabit.se

Thanks!