PLEASE Backup your wallet! A Paper Backup is *Forever*!

[MrMik]

How secure is a paper wallet with secureprint against a brute force attack?

Like in this scenario: Someone takes a photo of the paper backup, but the secureprint code is not on it.
S/he then uses a powerful computer with 'customised' Armory software to try to guess secureprint passwords.
The computer could be incredibly powerful, maybe something like an entry level smartphone made 10 or 20 years from now.

 My maths may be off, correct me please if below estimates are incorrect:

The Secureprint password is 11 letters long, and seems to be made up of numbers and letters only. Lets assume 26 upper case and 26 lower case letters, and 10 numbers, therefore 62 possibilities for each of the 11 letters. So that makes a maximum of  62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62 ⋅ 62
≈ 5.2036561* 10^19 combinations.

How long would it take to try them all?

[goatpig]

The Secureprint password is 11 letters long, and seems to be made up of numbers and letters only.

It's base58.

S/he then uses a powerful computer with 'customised' Armory software to try to guess secureprint passwords.
The computer could be incredibly powerful, maybe something like an entry level smartphone made 10 or 20 years from now.

Lol no. You think phones in the future will carry terabytes of RAM? The KDF is basically Scrypt, forget it.

[MrMik]

It's base58.

S/he then uses a powerful computer with 'customised' Armory software to try to guess secureprint passwords.
The computer could be incredibly powerful, maybe something like an entry level smartphone made 10 or 20 years from now.

Lol no. You think phones in the future will carry terabytes of RAM? The KDF is basically Scrypt, forget it.

Cheers, I looked that up and understand it much better now, but I don't really understand it.

Is my assumption correct that the "Target compute time 250ms" and "Memory usage 32MB" in the advanced settings during passphrase generation in Armory 0.96.3 is somehow related to this?

If a base58 - 11 digit password is enough to secure the paper backup, does that mean that an 11-digit password would also be sufficient as the passphrase for a wallet?

[goatpig]

Cheers, I looked that up and understand it much better now, but I don't really understand it.

Is my assumption correct that the "Target compute time 250ms" and "Memory usage 32MB" in the advanced settings during passphrase generation in Armory 0.96.3 is somehow related to this?

Each attempt requires a flat amount of RAM. This drastically reduces how many attempts you can perform in parallel. That's kind of the point of a decent KDF.

If a base58 - 11 digit password is enough to secure the paper backup, does that mean that an 11-digit password would also be sufficient as the passphrase for a wallet?

As long as your source of entropy isn't shit (please don't just put words together)

[Tanya_lya]

I like how this topic - of security and careful attitude to one's backup file+key becomes more & more popular. So crypto community cares about each other, we could say? 
If I've understood the topic starter, the only acceptable way of storing the info is on paper, if one wants his relatives to find the crypto treasures in case of an accident with the hodler. It seems reasonable, just as it seems fine to use other options (like those described here https://steemit.com/wallet/@guardawallets/what-s-up-with-your-backup-5-universal-safety-tips, for ex) for little sums or for everyday needs. I mean, in future, if/when crypto will be more widely accepted, there definitely will be solutions to use your assets quickly & easily, without searching for a paper.

[btcyonglin]

Hi etotheipi

I am a armory user
I have backup paper wallet
Now I want to recover this wallet

When I download armory wallet,it need to download all blockchain data.
It is so huge data,I can't download all these data.

How can I recover wallet without download blockchain data.
I want to move btc from armory wallet to a new hard wallet.
Can you tell me a simple way.
Thank you very mush

[joniboini]

How can I recover wallet without download blockchain data.
I want to move btc from armory wallet to a new hard wallet.
Can you tell me a simple way.
Thank you very mush

Follow what has been posted here: https://bitcointalk.org/index.php?topic=814314.msg9113171#msg9113171 (the offline mode part). You should be able to do it without downolading any blockchain data. However most HW does not support importing a private key. If your HW does not support WIF import, you could export the private key to another wallet like Electrum first, and then sweep the balance to your new address.

[HCP]

Hi etotheipi

etotheipi isn't responsible for Armory any more... it's all down to "goatpig"

When I download armory wallet,it need to download all blockchain data.
It is so huge data,I can't download all these data.

How can I recover wallet without download blockchain data.
I want to move btc from armory wallet to a new hard wallet.

You don't need Bitcoin Core synced and/or the blockchain data downloaded... in fact, you don't even need Bitcoin Core installed to recover your coins

You can simply do the following:

1. Download, install and run the latest Bitcoin Armory from here: https://btcarmory.com/


2. In Bitcoin Armory, "recover your wallet":



Then select the appropriate recovery type (most likely the first one):



Then select which format your Armory backup is in:



3. After you have recovered your wallet from the paper wallet, you can follow my guide here to export your private keys: https://bitcointalk.org/index.php?topic=4746784.msg43255691#msg43255691


4. Once you have your private keys exported, you can use a wallet like Electrum to import the keys and send to your Hardware Wallet

[waldis]

If I understand it correctly, the private address within my Armory wallet, on an offline computer (that has never ever seen a connection to the internet, with a destroyed ethernet port, so it could never see the internet), is going to stay as a static private key? All the addresses generated on my watch-only wallet will always point to the same private key, as well as all the change-back addresses will put the bitcoin back to the address that my private key will be able to unlock?

I'm just trying to understand how the private key that has never been connected to the blockchain will be able to unlock every single public address (out of gazillion that I generate with my watch-only wallet) that is recorded on the blockchain? I'm throwing in this question on purpose, trying to find out the missing link that would link all the bits in my brain together.

And, also, if a paper backup can unlock the private key in Armory, what if I access the private key, laser-engrave it on a metal plate (alloy that is pretty much indestructible - something similar to adamantium, but actually exists), and lock it up in the safest place I could come up with? In that case the backed-up (on a metal plate) private key would be much safer and much more versatile, since I would no longer be limited to the Armory software wallet?

Just trying to figure out how to keep my bitcoin in a case when one third of the planet earth gets destroyed.

[nc50lc]

If I understand it correctly, the private address within my Armory wallet, on an offline computer (that has never ever seen a connection to the internet, with a destroyed ethernet port, so it could never see the internet), is going to stay as a static private key? All the addresses generated on my watch-only wallet will always point to the same private key, as well as all the change-back addresses will put the bitcoin back to the address that my private key will be able to unlock?
-snip-

Yes, only if you're referring to the "root key" in your paper backup.
Armory is a "Hierarchical Deterministic" wallet which means that every private keys and addresses that it will generate can be recreated by the root key.

Otherwise, a single exported private key can only restore an address; one private key can only restore its address pair, not the whole wallet.

IDK if there's a way to get a 'master private key' from the 'root key' to be able to create a "versatile backup" but the instructions in the reply above you should be sufficient in case you need to export to another client.