Topic: What does HD Wallets meaning ? (Read 1038 times)

HD seeds are more for convenience rather than true bitcoin private key security.

lets say there are 12 word seeds and there are 1 million words in the english language.

the odds of someone RANDOMLY finding a combination is small.
million x million x million x million x million x million x million x million x million x million x million x million
=1 in 1000000000000000000000000000000000000000000000000000000000000000000000000 chance
even at 1000 combinations a second is only 31536000000 per year which still leaves
30000000000000000000000000000000000000000000000000000000000000 years

but, because words have structure. such as vowels and consonants it means that its slightly less random.. in human terms but even more less random in computer terms.

lets say 12 words of 6 letters long
applesorangebananapeanuttomatotissuesneezetriplesecondpriesthandlevalves
is not as random as
a9g6k3x6v3d7m2u5b7s8f9g5p6l2n4wj1aks6osc5gtq8lcu4wqk9xs3btald3fiuy9sl

because seeds dont use numbers there are only 26 character variations per byte instead of 36, and also knowing each word has vowels. allows the slightest of risks to reduce the randomness by smart people having pattern generators that that can shave off a bit of hashing requirement by knowing that a z doesnt appear much in words. or that a Y doesnt really follow an I but can follow a E quite often

but dont worry, even taking in some fancy english literature rules to reduce the hashing. it will still take
10000000000000000000000000000000000000000000000000000000 years+


but with that said
bitcoin core never is, will be or wants to be the user friendly version for grannies and teenagers to use.. its aim is 99.99% network security. and the ability to actually do transactions using bitcoin-core through a GUI is a side issue. usually for testing and debugging.

so putting fancy features into it is not their priority.. thats something other wallets can do for user friendliness so that bitcoin can contentrate on network security while other play around designing user friendly wallets

No Mycelium doesn't rely on a third party to secure your keys. Your keys are kept in your hardware wallet, so the user is always on total control of their secret keys.

True.. maintaining a wallet.dat updated is pretty annoying cause everytime you create a new recieving address you need to copy paste it into every single device that you are storing a backup

My question is: why is Core still dealing with this method of creating addresses if HD is so great? there must be some tradeoffs that make wallet.dat as it is now in Core not being HD, some security concenrs? or in the future we can enjoy HD in Core too and not worry about copying wallet.dat a million times?

the problem with backing up a wallet.dat. is that when you next send a transaction. it creates a new 'change' address created randomly and stores that to the wallet.dat.

making the backup instantly out of date as the backup doesnt have that new randomly generated change address, and requires re-backing up every time you do a transaction.

with HD seeds you dont need to worry
because private keys are created using the same seed.
laymens(not exact coding so dont judge)

key1=hash(mortalphilosophyvealspeciesporpoises1)
key2=hash(mortalphilosophyvealspeciesporpoises2)
key3=hash(mortalphilosophyvealspeciesporpoises3)
and so on
so as long as you know the seed eg mortal philosophy veal species porpoises    then the program will always be able to append the numberic sequence to get all the addresses attached to that seed

Great question (I did not know myself) and great answers too. I once thought that the wallet.dat held the blocks downloaded from the blockchain and it would be too costly to make a backup (lol). Although the wallet.dat is not that difficult to backup, It is even better to know you can memorize the passphrase and have a backup of your wallet in your head.

HD Wallet = generate a new address every time you receive a transaction
And of course it's more safer

At first i couldnt understand what was going on with my wallet when i installed an HD one since i was used to bitcoin core, But since using it i have found its much easier for maintaining privacy due to it automatically creating new addresses for you. Use mine most everyday now.

That's a really clever way to store your seed (the saving up character and lines and number of word in a page..) this way you would never forget (well as long as you get that enconded string of characters).

But something in me makes me to still trust more a wallet.dat file encrypted and hidden in some encrypted volume offline and with a couple of copies (with a password you can remember) since I heard about the brainwallet hack incident.

the seed can be stored any way you like. after all a wallet.dat file is just a file. so write your seed in notepad. save it. and then put it on several memory sticks .. just like you would with wallet.dat.

if you want it password protected. use winzip or winrar to zip the file and add a password to it. then no random prying eyes will see your seed.txt as clear plaintext as its locked into a passworded zipfile.

you can also do some crazy things too..

like get a random book. and as you read it. note the pagenumber, line and word of line where the individal seed words appear

eg an excert of chapter 65 of mobydick

imagine the seed was
mortal    philosophy    veal    species     porpoises

you can encode it
C65-L1-W2:C65-L3-W5:C65-L9-W15:C65-L7-W10:C65-L7-W13

where only you know its related to moby dick then save that to zip passworded file.

the other good thing is that before you even start. you can select your own words so that its easier to remember rather than being on paper thus not relying on words provided to you. but instead inputting words you want

It took me a while to figure it out as well at first. Then I had to start rushing around to find a pen and paper for my word string. At first I did not know what I was doing when I created the HD wallet good thing I wrote everything down

I tried to recover my wallets on different bitcoin wallet apps and it worked so I guess I don't need any passwords just to memorize the 12 words and it's good to go right?

I didn't know that it meant that. I thought that Multibit HD was standing for High Definition, a reference to it's nice interface.

Alright thanks for the reply, I could approximately guess the time needed to 12 words combination depends on the alphabet contained in one words, and possibilites etc,
but seems like it's gonna be safe for the next few year before quantum computing become mainstream, but I believe they'll update too.

Yes, absolutely possible. Just like its absolutely possible to brute force the privkey with millions of BTC on it. But it might take a few millions years. You might be surprised with how many words combination there is. Also the one i use has 21 words i think so its a even more crazy amount of possibility.

But 12 words does feel a bit lackluster in comparision, i'll give you that. And i think Multibit HD is BIP32, but thats just on top of my head, either way it doesnt really matter.

If I'm not wrong, which is BIP38 and BIP44 ?
btw is there any chance someone could generate lots of possible words combination and trying them one by one, so they might be possible of stealing the money in our wallet ?

HD has nothing to do with 3rd party, at all. So no. And no some HD wallet use different seed method, but that is outlined when you create or restore a wallet, it tells you which protocol it use.

So no, some wallet are compatible with some others, but this is a non-issue. You can simply restore the wallet with the original client, then move the funds to whatever wallet in the world you want.

No, I do understand that, the part I didn't understand is, does the recover of HD Account requires 3rd party verifications ?
Or they use a same standard across all HD wallets ? That means I could use my 12 words to recover on other HD Wallet Clients ?

I don't know how Electrum save its data, its definitively there somewhere but its probably not called wallet.dat.

I use Multibit HD which save a backup of it in a specific place every pretty much relevant moment + every X time. So you can recover your wallet with your password with that. If you lose your password, you need the words. If you lose both you're screwed.

Thanks a lot man, i was also having some doubt in HD meaning, now i understands it, i am using electrum hardware wallet , if i have lost it i just have to feed my seed key and i can open that wallet any where just i have to download windows installation wallet and feed my seed key and it opens it.

One doubt if i lost my seed key can i retrive my wallet with any other method, as their is no wallet.dat file in this wallet software.

All the same, there is a list of which relies on 3rd party and which does not on the bitcoin.orp's official page;
https://bitcoin.org/en/choose-your-wallet

HD means hyperdeterministic. Means with your wallet words, you can retrieve you wallet with just your words, no need for the wallet.dat etc. In a nutshell its a method of generating the subsequent privkeys. While non HD would have to be pre generated "manually" any keys after that would be lost if you did not have a wallet.dat backup.

More info;
https://bitcoinmagazine.com/articles/deterministic-wallets-advantages-flaw-1385450276