Bitcoins lost - old backup | Bitcointalksearch.org

jl2012

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Quote from: gmaxwell on December 02, 2012, 06:01:51 PM

Quote from: prezbo on November 29, 2012, 12:47:48 PM

this x 1000. I think newbies should start with electrum and go up from there if they need to.

And then get robbed because they don't understand the reduced security model of electrum. There is no replacement for understanding.

If the OP is confident that his coins were unrecoverable perhaps he could make his wallet files (the corrupted one, and the backups) and perhaps someone can recover the coins.

If you don't trust Electrum, use Armory

prezbo

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Quote from: flatfly on December 02, 2012, 06:43:35 PM

Every client has risks. When money is involved, it's important to look at the facts. So far, many more coins have been lost due to the way some things are implemented or poorly understood in the reference client than with Electrum's "reduced security model." In fact, I haven't heard of any Electrum users being robbed or otherwise losing their wallets.

Exactly. I only heard of users losing bitcoins because they didn't regularly backup their wallet, but I haven't yet heard of a single user that would lose bitcoins because they were fed wrong data by the server. Also there's also blockexplorer/blockchain.info to double check for the paranoid. And let's be perfectly honest here, until the satoshi client reduces the time it takes to download the blockchain considerably, it won't be really user-friendly.

flatfly

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090930

Every client has risks. When money is involved, it's important to look at the facts. So far, many more coins have been lost due to the way some things are implemented or poorly understood in the reference client than with Electrum's "reduced security model." In fact, I haven't heard of any Electrum users being robbed or otherwise losing their wallets.

gmaxwell

staff

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Quote from: prezbo on November 29, 2012, 12:47:48 PM

this x 1000. I think newbies should start with electrum and go up from there if they need to.

And then get robbed because they don't understand the reduced security model of electrum. There is no replacement for understanding.

If the OP is confident that his coins were unrecoverable perhaps he could make his wallet files (the corrupted one, and the backups) and perhaps someone can recover the coins.

Jutarul

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Quote from: DeathAndTaxes on November 02, 2012, 09:32:45 AM

In time hopefully the reference wallet will go to a deterministic model. Unique random private keys are simply to "fragile". It is to easy to lose coins. A deterministic wallet would always be safe if the seed is saved or backed up.

One might think that this should be a high priority on the todo list...

prezbo

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Activity: 430

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Quote from: jl2012 on November 29, 2012, 12:06:09 PM

Frankly speaking, people should not use the reference client (i.e. the "official" client) unless they fully understand what it is doing. All these kinds of bitcoin loss is fully avoidable with determilistic wallet (e.g. Armory, Electrum) with proper paper backup. I never trust an electronic backup because it may corrupt for many reasons.

this x 1000. I think newbies should start with electrum and go up from there if they need to.

Quote from: bitcoinvideos on November 29, 2012, 12:40:14 PM

This is very good to know but for people who are new into the world of BTC (me) and something I think I want to keep learning about. Armory, according to the Wiki, is in alpha but their site seems to show it as readily available and usable. Are you using it right now?

I started using armory recently. It has some cosmetic bugs, but other than that and being relatively resource intensive it works great. Especially the ability to create transactions and sign them offline is awesome. I can't wait for the new two-factor wallets.

bitcoinvideos

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Quote from: jl2012 on November 29, 2012, 12:06:09 PM

Frankly speaking, people should not use the reference client (i.e. the "official" client) unless they fully understand what it is doing. All these kinds of bitcoin loss is fully avoidable with determilistic wallet (e.g. Armory, Electrum) with proper paper backup. I never trust an electronic backup because it may corrupt for many reasons.

This is very good to know but for people who are new into the world of BTC (me) and something I think I want to keep learning about. Armory, according to the Wiki, is in alpha but their site seems to show it as readily available and usable. Are you using it right now?

jl2012

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Activity: 1792

Merit: 1111

Frankly speaking, people should not use the reference client (i.e. the "official" client) unless they fully understand what it is doing. All these kinds of bitcoin loss is fully avoidable with determilistic wallet (e.g. Armory, Electrum) with proper paper backup. I never trust an electronic backup because it may corrupt for many reasons.

Stephen Gornick

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Quote from: bitcoinvideos on November 29, 2012, 11:14:37 AM

copied the wallet.dat to a USB drive which is a Truecrypt volume then put it in my fire proof safe.

If the wallet.dat is using passphrase encryption the keys are safe even without also encrypting using TrueCrypt -- though that isn't going to hurt anything if you are comfortable with TrueCrypt and will remember that passphrase as well.

There are transaction details stored in the wallet.dat so some people encyrpt their wallet.dat backups to protect privacy with that as well.

But yes -- as long as your backup cycle occurs more frequently than every 100 transactions your backup strategy is sufficient. You can also increase the keypool size to a larger (or smaller) amount of keys if there is a chance you might make 100 transactions during the month.

bitcoinvideos

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So then if I used some sort of monthly recurring schedule that I stuck to I would be relatively safe is what I am gathering. I encrypted the wallet right away before doing anything so that part is good. Last night I closed out bitcoin, copied the wallet.dat to a USB drive which is a Truecrypt volume then put it in my fire proof safe. Each month, around the 15th or so, I plan on updating that file with the most recent copy. I also thought about creating a 2-5mb truecrypt volume and dropboxing that file more frequently...

DannyHamilton

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Quote from: bitcoinvideos on November 28, 2012, 11:22:54 PM

I know this is a little late but I wanted to piggy back off this and ask what might be a dumb question...what happens if I have an old backup which is encrypted on a USB drive stored away and I restore this? Does it simply sync back the new transactions to the addresses? Assuming I have not used 100 addresses or is it 100 transactions?

Yes. The transactions are stored in the blockchain. The wallet.dat has the private keys associated with your addresses allowing you to create transactions. The standard default configuration of the program pre-generates 100 addresses and stores them in the wallet. Each time you use an address/private key, it is taken from this pre-generated pool, so if you receive/send any bitcoin after the backup those transactions will generally be found when you restore the wallet.

A couple of notes on this process:

When you encrypt your wallet, it throws away all the unused pre-generated addresses and regenerates 100 addresses with encrypted private keys. This means that If you perform some transactions that use the pre-generated addresses after encryption, but restore the wallet from before encryption, then it won't find those transactions that used addresses from the encrypted pool of addresses.
It is 100 addresses that you are concerned with, however most transactions to send coins program secretly use addresses without telling you. If you want to send 2 BTC to Sally, your client program will likely send more than 2 BTC and spllit the recipients with 2 BTC going to Sally's address and the remaining "change" being sent back to one of the pre-generated addresses. You won't see this address listed in the user interface of the program, but it still uses up one of the 100 addresses.

DeathAndTaxes

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Gerald Davis

Quote from: bitcoinvideos on November 28, 2012, 11:22:54 PM

I know this is a little late but I wanted to piggy back off this and ask what might be a dumb question...what happens if I have an old backup which is encrypted on a USB drive stored away and I restore this? Does it simply sync back the new transactions to the addresses? Assuming I have not used 100 addresses or is it 100 transactions?

Yes. It really isn't syncing though. When the client loads the wallet.dat it uses the blockchain to find any unspent outptuts sent to any address in the wallet. It them sums up the value of all the unspent outputs and displays that as the "available balance". The client doesn't know the wallet.dat is an "old backup". Any wallet, any time it compares the addresses in the wallet to the blockchain, locates all the unpsent outputs, and totals their value.

The issue with "old" backups is that you may have received coins at an address (and thus private key) which is NOT in the backup. If the address & private key are not in the backup well there is no way to recover those funds. The limit is technically 100 NEW addresses however everytime you SENT (not receive) coins you use a new address as change so you can think of it as 100 transactions.

bitcoinvideos

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I know this is a little late but I wanted to piggy back off this and ask what might be a dumb question...what happens if I have an old backup which is encrypted on a USB drive stored away and I restore this? Does it simply sync back the new transactions to the addresses? Assuming I have not used 100 addresses or is it 100 transactions?

DeathAndTaxes

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Gerald Davis

Quote from: tofu on November 02, 2012, 08:38:46 AM

~~I think~~ I'm out of luck.

All payments are done to the encrypted wallet but I have 4000 movements and the wallet.dat backup it's from movement 0.

The problem here is the backup it's too old and it doesn't has the addresses with the incomings Sad

good to know for the next time.

Mystery solved. Remember the default keypool is 100 tx. So you need to make backups at least once every 100 txs (I would say once ever 50 to be safe). You can however extend the keypool. For example bitcoind -keypool=2000 would make the keypool 2000 and reduce the frequency of backups (at the expense of a larger wallet).

In time hopefully the reference wallet will go to a deterministic model. Unique random private keys are simply to "fragile". It is to easy to lose coins. A deterministic wallet would always be safe if the seed is saved or backed up.

Raoul Duke

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have you tried to use -salvagewallet ?

You can also try to use pywallet and see if it dumps something.

Code:

./pywallet --dumpwallet --password="Whatever your passphrase is"

It will probably not work because of the wallet corruption, but you should at least try.

tofu

newbie

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I think I'm out of luck.

I encrypted the wallet and I started to bet satoshi dice. All payments are done to the encrypted wallet but I have 4000 movements and the wallet.dat backup it's from movement 0. So I think I definitelly lost the btc. Well, Now I know a bit more of bitcoin system

Fortunatelly I keep 50% of my winnings before start this new wallet.

by the way, I don't delete .bitcoin/ directory, I just move to .bitcoin_old1 .bitcoin_old2 ... to keep it just in case.

The problem here is the backup it's too old and it doesn't has the addresses with the incomings Sad

good to know for the next time.

Thank you to all for your help!

Stephen Gornick

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Quote from: CIYAM on November 01, 2012, 07:48:14 PM

if you had issued tx's *after* you encrypted the wallet then the chances are very slim that the backup of the unencrypted wallet will be of any use

Just to clarify, what that is referring to is after encryption, none of the addresses used for change will have existed in the backup that was made prior to encryption.

But that doesn't mean the old backup has no value after encryption. Encryption only flushes the key pool, it doesn't touch any bitcoins that were in the old wallet. Only spending those coins after encryption would cause the change to go to new addresses that didn't previously exist. So the old backup could still have some or all of the coins yet.

Of course, the encrypted wallet should not be missing anything, so like CIYAM suggested, -rescan

Then if things still don't add up, look at the transactions to see if there are any that shouldn't be there.

CIYAM

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Ian Knowles - CIYAM Lead Developer

Quote from: tofu on November 01, 2012, 12:32:12 PM

I have two backups one encrypted (after encryption) and one without encryption (after creation)

Okay - if you had issued tx's *after* you encrypted the wallet then the chances are very slim that the backup of the unencrypted wallet will be of any use (this has happened to others).

So assuming that you using the backup of the encrypted wallet and that no errors are occurring you might need to run bitcoin with the -rescan option.

nelisky

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So you are using the same wallet.dat file from .bitcoin/ before delete, or are you using an old backup of your wallet.dat?

If the latter, and depending on how often you make payments, you might have a too old wallet that doesn't have the addresses where you have most of your btc. By default the bitcoin client keeps 100 addresses in a pool and uses these as needed, so if you made a backup, made more than 100 payments and then recovered that wallet you might be out of luck.

Rule of thumb: don't delete ANYTHING until you are sure there's nothing more to do. If you need to clean up .bitcoin/, just move it somewhere else and create a new directory.

tofu

newbie

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the original wallet.dat says "wallet.dat corrupt, savage failed"

Topic: Bitcoins lost - old backup (Read 2549 times)