Bitcoin Forum

Bitcoin => Hardware wallets => Topic started by: moztec on February 03, 2018, 09:08:40 PM



Title: How does a Ledger Nano S work?
Post by: moztec on February 03, 2018, 09:08:40 PM
So, let's assume I buy a Nano Leder S and put my bitcoins in it.
Then my Nano Ledger S gets stolen but I kept my secret word seeds at a good place so I can restore on a new one.

Questions:

1. Can't the thief just try to unlock it by "bruteforcing" the pincode?

2. If I restore my btc on a new nano ledger s, how does it know all the receiving addresses by just having the word seed?
If I understand correctly the nano ledger s will use a different receiving address for every incoming bitcoin transaction.
So it has to have a way to know about all those addresses somehow, but how?
Does it rely on any manufactureres service for keeping track on this?

3. What if this happens in say 10 years.. Let's assume the nano ledger S devices are not available anymore and the manufacturere went bankrupt -> No support.
Can I still recover my btc without a nano ledger s device somehow??

4. Can the nano ledger S be used with anything else than chrome apps? It sounds like a broken solution to only have apps that rely on google chrome.
Isn't there any application that can use it natively?

Thanks for your replies!




Title: Re: How does a Ledger Nano S work?
Post by: achow101 on February 03, 2018, 09:19:51 PM
1. Can't the thief just try to unlock it by "bruteforcing" the pincode?
Not really. There's a delay between PIN entries which means that a brute force will take a significant amount of time. Furthermore, you can use the passphrases option to further hide your coins; without the correct passphrase, the correct private keys cannot be derived.

2. If I restore my btc on a new nano ledger s, how does it know all the receiving addresses by just having the word seed?
If I understand correctly the nano ledger s will use a different receiving address for every incoming bitcoin transaction.
So it has to have a way to know about all those addresses somehow, but how?
The mnemonic follows the BIP 39 specification to encode a seed value. That seed value uses BIP 32 to derive all of the private keys used by your wallet. Thus the seed holds all of the information that is necessary to reconstruct the private keys for your wallet.

Does it rely on any manufactureres service for keeping track on this?
No.

3. What if this happens in say 10 years.. Let's assume the nano ledger S devices are not available anymore and the manufacturere went bankrupt -> No support.
Can I still recover my btc without a nano ledger s device somehow??
Yes. You just need any wallet software that follows the BIP 39 and BIP 32 specifications. These are publicly documented and well specified. Even if such software does not exist, you could write or hire someone to write software that follows the specs.

4. Can the nano ledger S be used with anything else than chrome apps? It sounds like a broken solution to only have apps that rely on google chrome.
Isn't there any application that can use it natively?
Yes. any wallet software which supports the Ledger Nano S can be used. libraries for interacting with it are publicly available so wallet software can just use those. An example of one is Electrum.


Title: Re: How does a Ledger Nano S work?
Post by: HCP on February 04, 2018, 04:20:25 AM
1. Can't the thief just try to unlock it by "bruteforcing" the pincode?
Not really. There's a delay between PIN entries which means that a brute force will take a significant amount of time. Furthermore, you can use the passphrases option to further hide your coins; without the correct passphrase, the correct private keys cannot be derived.
Just a minor correction here... the Ledger Nano S doesn't use an exponential PIN code delay like the Trezor... you only get 3 chances to enter the correct PIN code, then the device wipes itself. So, Brute forcing the PIN is basically impossible.