Quote from: ErisDiscordia on Today at 05:36:24 AM

Quote from: nullius on April 27, 2021, 03:54:30 PM

Quote from: Farmer Bill on April 27, 2021, 03:45:49 PM

The application of this for Bitcoin could be to code your wallet seed phrase in this way by choosing a book and finding those seed words in the book and converting them to 5 digit numbers.

Without knowing from which book and the exact print edition (your key), your seed phrase is reasonably safe.

The cryptographers here will be able to punch holes in this but for good enough protection for regular folk it could work quite well.

Yes, they will. So don’t do it.

*snipped brainwallet talk*

Using phrases from books as your seed phrase seems obviously insecure. Even if you use a further encryption method of your own design.

What about passphrases, though? Let's say you have your seed properly generated & stored in a secure manner. How much additional security would a six word phrase from a book provide? What about six words, picked from one book, using a method of your own design? How would the entropy generated this way compare with the entropy of six randomly generated words (such as throwing dice & picking words from the diceware list)?

Random six word passphrases are generally recommended as secure enough. Their downside is that while they are much easier to remember than secure strings of alphanumberic + symbols, they are still hard to remember, especially if you use more than a few. When using a method to generate 6 words from books, you just have to remember the method and which books you used. Is it comparably secure to storing your passphrases in a password manager or on paper in a hidden location?

This way, your wallet has 3 layers of protection: your seed phrase, your passphrase generation method and the knowledge of which particular print of a book to use. At this point I believe your biggest risk of loss is clearly yourself & the multiple points of failure you have set up

You are also correct about the multiple points of failure and have abandoned this idea.

For years I ran a node with Bitcoin core wallet then used Armory with offline transaction signing.

Then I had some problems with Armoury about the time ATI finished with the project and Goatpig continued with development. I managed to recover my coins and bought a ledger.

Generated BIP39 Mnemonic 24 words.

I wish to store these words on a 2 of 3 paper backup and hide them.
It seemed a simple task.

So scouring through a book for these 24 words and assigning each a 5 digit code based on page number line number and position of word within the line. Then noting these down pencil on paper and hiding them would probably be meaningless to the finder.
I may just use the 24 words plus 1 method for extra security and commit this to pencil and paper in addition to being in my head.

With Bitcoin bobbing about in the mid $50k's all is well.