Did you make a backup of your private key?

Is this safe and can you lose the key?

At first I am using the Ledger Nano S. With the Ledger I have a good feeling that nobody else hase access to my private key.

But what happens to private keys if the stick doesn't work anymore. No problem for this I have the recovery sheet with a 24 words recovery phrase. I buy a new stick and make a recovery with the 24 words recovery phrase.

But what happens if the recovery sheet is lost or stolen?

If somebody else has your recovery sheet, then he can recovery your keys and has access to your coins. And if the recovery sheet is lost. Either you have it on your stick or it is lost.

So I have designed a new recovery sheet which can be safe and redundant.

My requirements were

redundant in case if I lose it
safe that it is not possible to recover with only one sheet.

The result was the 2 of 3 recovery sheets.You need at least 2 sheets to get the 24 words recovery phase

Advantages:

You can lose one sheet and you can still recover the ledger
If a thief has only one sheet it is not possible to recover the ledger and coins

Reason for Safety:

One sheet has 16 words of 24 words. One word has 2048 possibilities or 11 Bit.

24 words * 11 Bit = 264 Bit

256 Bit master key and 8 Bit hash checksum

So 8 words have to be guessed:

This means for a brute force attack: 8*11Bits – 8 Bit CS = 80 Bit

2^80 = 1.21 e+24 attempts.

If an ASIC can calculate up to 15000 GHashes/s then my estimation is up to 2500 years.

Do you have tips to store these 3 recovery sheets?

My idea was:

Use 3 different locations for the recovery sheet:

Example: Home, office, online banking account, etc.

Or give one sheet to your sister, brother. One you can store in lasthello. One at home.

Alternatives recovery sheets and caclulation:

Template download:

https://bitcoin96227362.files.wordpress.com/2018/01/redundantledgerrecoverylist_v2.pdf

Be sure that nobody has access to 2 or more of your sheets!

Use of this procedure on your own risk!

Store the document in a safe place!