Define a Secret Seed Phrase (Mnemonic)

Challenge

A secret seed phrase shall be:

• known by you.
• not known by others.

The latter one might be broken when you create a Seed Phrase without special care, considering nowadays possibilities with internet technologies, spyware and cyber security vulnerability holes. With the following recommended steps your Seed Phrase should become available to you only.

Following links also give input how important it is to keep your Mnemonic secret:

• bitcoinbriefly.com
• ledger.com

Proposed Steps to Follow

• Take yourself at a place not being watched, neither directly nor though cameras, mirrors nor windows.
• Choose random words for your seed phrase, in a random order.
  • Take a pen and a sheet of paper, randomly choose 12 words from the BIP39 wordlist. You might use a manual dice (no software!).
  • Write down the 16 words after the 12th word.
    • Info: the 12th word is used for a checksum. Since manually chosen, it might not be usable as checksum, thus might have to be replaced in a later step.
• Finalise the Mnemonic and identify a Bitcoin address:
  • Ensure you have a PC free of cyber attacking / spying software.
    • Best: a new PC, delivered directly to you by an official dealer, never being connected to the internet.
    • OK: Your PC, having installed the latest operating system and browser updates, having installed only trustworthy and updated applications.
    • Not ok:
      • a public PC.
      • a PC having / having had installed outdated applications or non-trustworthy applications.
  • Shutdown and restart your PC, this to quit any application.
  • Quit any application/process/task that started automatically – you might leave your virus scanner, firewall running.
    • Consider also to kill applications behind the icons in your task panel or background processes (see also Windows task manager).
    • Hint: If a needed process is killed by accident, after a restart your PC shall work as expected.
  • Start only a browser and download the bip39-standalone.html file of the BIP39 Tool, i.e. the “Mnemonic Code Converter”
    • Direct link to the html file: https://github.com/iancoleman/bip39/releases/download/0.5.3/bip39-standalone.html
    • BIP39 Tool with manual: https://github.com/iancoleman/bip39
    • Hint: To increase security you shall really download the file and not use the online version!
  • Quit your browser.
  • Put your PC offline, e.g. switch off Wifi, unplug the LAN cable, or even unplug the router.
  • Open your browser, and open a new “private” window.
    • This private mode will ensure your browser history is deleted afterwards.
  • In this private browser window open the downloaded bip39-standalone.html file.
  • Setup the BIP39 tool:
    • In “Mnemonic”:Activate “Hide all private info”.
      • Select “Coin” the value “BTC – Bitcoin”
    • In “Derived Path”:
      • Select “BIP84” – to generate Bitcoin addresses starting with bc1 – allowing to be used by the most wallets.
    • In “Derived Addresses”:
      • Click on “Toggle” to later hide any values except the Address column, especially hide the “Public Key” and “Private Key”.
      • Click on “CSV” to only display the Address value, without further features like QR code generation.
      • In “Show” define, that only 1 more rows will be loaded.
  • Define your secret Mnemonic:
    • In “Mnemonic” enter your chosen 12 words in your chosen order.
    • If the tool displays “Invalid mnemonic”:
      • Ensure you have entered the words correctly; all are lower-case only.
      • Choose for the 12th word its next word of the BIP39 wordlist, as long as the mnemonic is accepted. This at maximum has to be done 16 times, and ensures, the 12th word is a valid checksum.
  • Write down on a sheet of paper:
    • the final Mnemonic.
    • the address in section “Derived Addresses”, starting with “bc1”.
  • Close the browser window and the browser application.
  • Delete the bip39-standalone.html file. Also clear it from an eventual trash bin.
  • Restart your PC, to clear eventually existing information from the clipboard or RAM.
  • Feel free to connect your PC to the internet.
  • To keep your Mnemonic secure, you might transfer the words on your sheet of paper e.g. to metal plate(s) and store those on secret place(s).
• Test your Bitcoin address:
  • Open a bitcoin block explorer, e.g. from blockchain.com.
  • Enter your Bitcoin address, and verify if valid details are displayed.
  • Info:
    • You can use this address (e.g. encoded in a QR code) to send funds to this Bitcoin address with any wallet supporting BIP84 addresses (i.e. ones starting with “bc1”). Feel free to share this address to others.
    • You can use a block explorer to verify the containing funds.
    • You can access the funds to e.g. transfer funds to other addresses, by using a Bitcoin Wallet and entering there your Mnemonic. Take care to keep the high level of security of your Mnemonic achieved by following the above steps, i.e. use it wisely!