Safest way by far is twelve words in your head, assuming no implants.

It’s not something you really want to take on vacation, but I’ve actually done it when delivering by hand overseas. Went through TSA just fine—in its case it’s just a black image on their scanner.

Bonus: Gave me a chance to orange-pill TSA agents, too. They really liked the key.

What can I share with you? I try to spell it all out in the website, but happy to answer questions here.

May we suggest a modulo bitcoin key?

https://modulo.network

Why do people like that always think they are smarter than everyone else?

You are exactly right that the seed phrase can be generated offline regardless of the checksum. The checksum is only necessary when entering into technology, and wallets should support that. There are some entropy bits necessary in the final word that need to be made, but they are few.

We put this concept into the wallet we are making: https://lightninginajar.xyz where you can import your seed words and final bits in the 12th word slot. Still alpha, but if you try it let us know any feedback.

For interest and educational purposes, there are two particular spreadsheets that show it:

1) list your 11 or 23 words and it shows the qualifying checksum words, and;

2) list your 11 or 23 words and remaining bits, and calculates the checksum.

They can be found at https://modulo.network/spreadsheets/

Gotcha—sorry for the trouble.

Send me a dm and I’ll send you a lightning invoice and get the details.

You pay to a QR code on the website. Hit generate QR and enter your shipping details. (#btcpayserver 🧡)

Thank you. It is binary as you have probably surmised, and you must be careful when converting to the seed words. We recommend repeating 3-4 times, just to be certain, and ensure you have backups like any good private key setup. Add a passphrase when setting up addresses, too.

Every bitcoiner must decide when to encounter technology. Modulo keys push it away from the key generation stage.

To purchase a key?