Another Cold Storage Question

[spectre1989]

Hi everyone,

Sorry if this has already been covered, I've just spent an hour reading other threads about cold storage and couldn't find any that answered my question, but there might be one out there.

I've just finished setting up some cold storage, I've got a bunch of encrypted USB sticks with my wallet on them, and also a "failsafe" paper printout of my private key (the wallet only has one payment address in it), which will be stored somewhere safe. However, I came across this in the wiki:

The situation is made somewhat more confusing because the receiving addresses shown in the UI are not the only keys in your wallet. Each Bitcoin generation is given a new public key, and, more importantly, each sent transaction also sends some number of Bitcoins back to yourself at a new key. When sending Bitcoins to anyone, you generate a new keypair for yourself and simultaneously send Bitcoins to your new public key and the actual recipient's public key. This is an anonymity feature – it makes tracking Bitcoin transactions much more difficult.

So this being the case, does this mean that if I in future move any funds out of cold storage, I need to back up my wallet again? Does this also mean that my paper printout of my private key is not enough? Are there any Bitcoin clients which don't have this anonymity feature, and therefore the one private key is sufficient?

And finally, I know the answer is probably no, but I just want to make sure. To make sure that my cold storage works, I was going to send a small quantity of coins to it. Then create a new temporary wallet, import my private key, double-check the funds are there, and then destroy the temporary wallet. Does the process of importing a private key do anything weird like creating new addresses or distributing funds to other addresses for anonymity? I know that question is rather stupid, but I just want to make sure!

Thanks
Spec

[cr1776]

Hi,
1. The wiki is right.  Maybe put most coins you don't intend to spend in there, keep some in a different wallet. You'll want to rebackup them, yes.
2.  One of the deterministic wallets - armory etc - May do that, I am not 100 sure
3. You could just verify the address had the funds on blockchain.info for example without importing unless you have another reason to do so

:-)

[spectre1989]

Hi,
1. The wiki is right.  Maybe put most coins you don't intend to spend in there, keep some in a different wallet. You'll want to rebackup them, yes.
2.  One of the deterministic wallets - armory etc - May do that, I am not 100 sure
3. You could just verify the address had the funds on blockchain.info for example without importing unless you have another reason to do so

:-)

Thanks

[Gabi]

So this being the case, does this mean that if I in future move any funds out of cold storage, I need to back up my wallet again?

YES.

If the client you use does that (send the change to a new address) then YES, you have to reprint it. This is an important thing often overlooked.

[spectre1989]

OK, so given that there may not at present be a wallet client which can handle sending funds without generating a new address, I'll just not move funds out of cold storage for a while. It'd be so laborious to update all of my backed up wallets, plus I'd have to print out a paper wallet instead of just being able to write down a private key (which I prefer to do). So I'll just leave some in an exchange or something, that way I can use it for day-to-day purchases.

So finally then, is anyone able to confirm or deny whether the wallet creating new addresses when you send funds, is a feature of the wallet, or an intrinsic feature of bitcoin?

[umaOuma]

So finally then, is anyone able to confirm or deny whether the wallet creating new addresses when you send funds, is a feature of the wallet, or an intrinsic feature of bitcoin?

It is just feature of the wallet. Yo can create+sign raw transaction where change address is the same as the address you send the BTC from

[spectre1989]

So finally then, is anyone able to confirm or deny whether the wallet creating new addresses when you send funds, is a feature of the wallet, or an intrinsic feature of bitcoin?

It is just feature of the wallet. Yo can create+sign raw transaction where change address is the same as the address you send the BTC from

Awesome, is that possible to do with bitcoin-qt, or would I need armory or some other wallet?

[miken123]

If you use Bitcoin-QT (or any wallet client, including some web ones, that allow you to import private keys using just the priate key) you should be able to import the wallet, send money out, and then remove that address from your wallet once again.

It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key.  But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again.  All without having to update all your backups.

Similarly you can, as you stated, just send money to that public address of your paper wallet's whenever you want to store some more there.



Blockchain.info's wallet lets you "import" paper wallets without sending the money out of that address (it asks if you want to "sweep" the wallet, and even recommends it but you can say no and it will just bring in the wallet address -- however I don't know of a way to 'delete' that address from your account's record after that on blockchain.info).

[DannyHamilton]

If you use Bitcoin-QT (or any wallet client, including some web ones, that allow you to import private keys using just the priate key) you should be able to import the wallet, send money out, and then remove that address from your wallet once again.

It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key.  But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again.  All without having to update all your backups.

This is HORRIBLE advice.  Advice such as this almost guarantees that someone will permanently lose bitcoins.  Please refrain from giving advice on how to secure your wealth when you ahve no idea what you are talking about.  Some uneducated newbie might actually believe you!

[everd1213]

Sorry,

I wanted to reply to https://bitcointalk.org/index.php?topic=227766.msg3722592#msg3722592 from "micax1".
Could not find another way around while I am still in ''quarantine".   

Micax1:
Yes, I have over 20 blocks - orphaned, in the blink of an eye!
Just us?

Can somebody forward this message to micax1

Regards.

[Gabi]

That "change coins go to a new address" thing should be made clear. Almost no one know it. It is a catastrophe waiting to happen

[miken123]

If you use Bitcoin-QT (or any wallet client, including some web ones, that allow you to import private keys using just the priate key) you should be able to import the wallet, send money out, and then remove that address from your wallet once again.

It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key.  But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again.  All without having to update all your backups.

This is HORRIBLE advice.  Advice such as this almost guarantees that someone will permanently lose bitcoins.  Please refrain from giving advice on how to secure your wealth when you ahve no idea what you are talking about.  Some uneducated newbie might actually believe you!

Hmm I believe you're right given your num of posts... But could you explain your reasoning (rather than just 'get mad')?

[DannyHamilton]

If you use Bitcoin-QT (or any wallet client, including some web ones, that allow you to import private keys using just the priate key) you should be able to import the wallet, send money out, and then remove that address from your wallet once again.

It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key.  But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again.  All without having to update all your backups.

This is HORRIBLE advice.  Advice such as this almost guarantees that someone will permanently lose bitcoins.  Please refrain from giving advice on how to secure your wealth when you ahve no idea what you are talking about.  Some uneducated newbie might actually believe you!

Hmm I believe you're right given your num of posts... But could you explain your reasoning

When you send a transaction after importing your private key, the Bitcoin-Qt wallet will create a brand new address with a brand new private key that it doesn't tell you about.  It will send the "change" from the transaction to this new address.  Note, since this address is new, it is NOT part of your paper wallet.  When you suggest to "be sure that you deleted any trace within your memory or hard drive", the typical user is going to delete the wallet.dat file that they imported the private key into.  In doing so, they will have deleted this newly created private key and address.  Since this new private key isn't part of their paper wallet, they will have permanently lost access to any bitcoins that will have been sent to this "change" address.

[miken123]

If you use Bitcoin-QT (or any wallet client, including some web ones, that allow you to import private keys using just the priate key) you should be able to import the wallet, send money out, and then remove that address from your wallet once again.

It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key.  But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again.  All without having to update all your backups.

This is HORRIBLE advice.  Advice such as this almost guarantees that someone will permanently lose bitcoins.  Please refrain from giving advice on how to secure your wealth when you ahve no idea what you are talking about.  Some uneducated newbie might actually believe you!

Hmm I believe you're right given your num of posts... But could you explain your reasoning

When you send a transaction after importing your private key, the Bitcoin-Qt wallet will create a brand new address with a brand new private key that it doesn't tell you about.  It will send the "change" from the transaction to this new address.  Note, since this address is new, it is NOT part of your paper wallet.  When you suggest to "be sure that you deleted any trace within your memory or hard drive", the typical user is going to delete the wallet.dat file that they imported the private key into.  In doing so, they will have deleted this newly created private key and address.  Since this new private key isn't part of their paper wallet, they will have permanently lost access to any bitcoins that will have been sent to this "change" address.

Thanks for the clarification. I appreciate it.  
I swear I have done such an import through the Bitcoin-QT command prompt and it brought in the address into my wallet without creating a new one... But it was a few weeks ago and I was learning a lot back then. Maybe I missed something?  I also did this on a blockchain.info import. It even asks if you want to sweep to a new address (recommended) or not.   
anyway I didn't mean to mislead anyone.

[rvdb1984]

If you use Bitcoin-QT (or any wallet client, including some web ones, that allow you to import private keys using just the priate key) you should be able to import the wallet, send money out, and then remove that address from your wallet once again.

It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key.  But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again.  All without having to update all your backups.

This is HORRIBLE advice.  Advice such as this almost guarantees that someone will permanently lose bitcoins.  Please refrain from giving advice on how to secure your wealth when you ahve no idea what you are talking about.  Some uneducated newbie might actually believe you!

Hmm I believe you're right given your num of posts... But could you explain your reasoning

When you send a transaction after importing your private key, the Bitcoin-Qt wallet will create a brand new address with a brand new private key that it doesn't tell you about.  It will send the "change" from the transaction to this new address.  Note, since this address is new, it is NOT part of your paper wallet.  When you suggest to "be sure that you deleted any trace within your memory or hard drive", the typical user is going to delete the wallet.dat file that they imported the private key into.  In doing so, they will have deleted this newly created private key and address.  Since this new private key isn't part of their paper wallet, they will have permanently lost access to any bitcoins that will have been sent to this "change" address.

Thank you for this very Helpful post.

Just to be sure: If you load your private key into the qt and subsequently sent the amount to a new paper wallet, then it is safe to delete all data on your computer, right?

And one next question: if i load a private ket into the qt, sometimes the qt crashes. After re-opening the cq, the amount is however present. Now, I was wondering: what will happen if the amount does not get updated after such crash? Can is retry to load the private key, or are my coins lost in translation? Or, maybe in other words, as long as the coins are not spent, do they remain linked at the paper wallet address or are they sent to the main qt address?

Many thanks!