export/backup of encrypted wallet to reduce risk of losing BTC

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In the current state of the app it is possible to create transactions that will 
never confirm, so this money is lost, if it is not possible to clean app data 
and reinstall the old wallet. Also other unknown issues might block me from 
sending coins from the device. Therefore it is risky to store BTCs in the app. 
This risk could be completely worked around if it would be possible to export 
the wallet and reimport it later after data has been cleared or a new version 
of the app was installed. The encryption key could be the AndroidID or a user 
entered password.

This would allow to put the app through some real world use, because the money 
cannot be lost by app bugs.

Original issue reported on code.google.com by ingo.bor...@googlemail.com on 13 Jul 2011 at 8:59

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First, a question: How do you know that the tx will never confirm? Is it an 
observation?

Apart from that, yes I plan to allow extracting the private key in some form, 
so that you can import it into the Satoshi client for example.

There is already a backup of the key on the device, in case the wallet file 
gets corrupt.

Original comment by andreas....@gmail.com on 14 Jul 2011 at 1:16

• Changed state: Accepted

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Original comment by andreas....@gmail.com on 14 Jul 2011 at 1:19

• Added labels: Priority-High, Type-Enhancement
• Removed labels: Priority-Medium, Type-Defect

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Yes, it is an observation, the transaction is sitting unconfirmed for ~3days in 
bitcoin-wallet. The reason is probably that the tx is too small (0.001BTC) and 
without fee and it seems to not even be relayed by peers. At least I cannot 
find it anywhere in the bitcoin network as an unconfirmed tx. So not a real 
issue, except that probably also other people will try the client first with 
small tx amounts and be dissapointed that it does not work. Two bigger tx 
worked fine for me. 

Apart from that, the app could also fail in other ways, so in general it is 
good, if the wallet can be exported to reclaim funds with another client or a 
newer version of this software.

Original comment by ingo.bor...@googlemail.com on 14 Jul 2011 at 6:24

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Some miners care about transaction fees. But none of them care about 
transaction amount that I know of. I think, somehow, your client has failed to 
send the transaction to any peers.

Original comment by omnifari...@gmail.com on 15 Jul 2011 at 8:56

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Seems some small transactions without fees will not be relayed by peers:
http://forum.bitcoin.org/index.php?topic=28462.msg358407#msg358407

Original comment by ingo.bor...@googlemail.com on 15 Jul 2011 at 9:03

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I too can verify that small transactions get 'lost'.  I've had a pending 
transaction for quite a while as well. I've tried restarting the client, 
restarting the phone and setting preferred peer.  The ability to export/import 
a wallet would be a significant plus.   Perhaps adding the ability to tell the 
client to reinitialize the wallet by rescanning the chain would help?

Original comment by imsa...@gmail.com on 21 Jul 2011 at 12:25

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Can we keep the topic of this issue at exporting the private key of the wallet 
only?

Transaction fees --> http://code.google.com/p/bitcoinj/issues/detail?id=45
Small transactions getting lost --> 
http://code.google.com/p/bitcoin-wallet/issues/detail?id=16 or open a new issue

Original comment by andreas....@gmail.com on 21 Jul 2011 at 12:38

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biggest problem wallet-export:
what about the exporting function mentioned in july in this post? even with 
high priority it is not yet included in the latest version (1.36)! yes, it is 
truly high prio because it is surely very important! w/o this function, the app 
is pretty worthless because of a too high risc loosing all your coins 
(app-crash) and having no backup of your private keys (wallet). and the 
described manual backup of the wallet (readme) works only for rooted devices - 
not all are rootable.
so the next update should really have this important feature; plz.!

Original comment by vn654...@googlemail.com on 18 Oct 2011 at 10:10

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Issue 66 has been merged into this issue.

Original comment by andreas....@gmail.com on 4 Dec 2011 at 2:43

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Some update on this issue:

I have a working encrypted backup implementation ready in a branch. However, 
what's missing is a restore:

- Bitcoin Wallet itself currently is still not good at handling multiple keys 
and it would need to rescan the whole blockchain after restore

- The Satoshi client still is not able to import keys

- The very least I would like to support that the user can decrypt their backup 
with standard tools like openssl or gpg. However, I could not find their key 
derivation function and thus did not manage to implement this in a compatible 
way. If someone is good at implementing standard cryptography, specifically the 
algorithm that derives the encryption key from a passphrase, you could help me 
a lot

Original comment by andreas....@gmail.com on 5 Dec 2011 at 11:57

• Changed title: export/backup of encrypted wallet to reduce risk of losing BTC

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Could you also back up the transaction data with the keys, or would you still 
have to validate that by rescanning the block chain?

Original comment by chrisr...@gmail.com on 20 Feb 2012 at 6:36

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If there was a way to export/backup your private key, it's really all you need 
to recover your funds as the ledger is kept on the bitcoin network.

Original comment by kallist...@gmail.com on 23 Feb 2012 at 3:13

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What's the status on this thing? Is the wallet already encrypted as it is?

Original comment by christia...@gmail.com on 26 Feb 2012 at 2:17

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I followed the directions at 
http://gary-rowe.com/agilestack/2011/12/28/how-to-recover-lost-bitcoins-from-an-
android-wallet/ and was able to get my private keys; however, I've yet to find 
anything that will allow me to import those keys.  The wallet service at 
blockchain.info gives an error regardless which of my four keys I feed it.

Original comment by danbowk...@gmail.com on 25 Mar 2012 at 3:51

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As a followup to my last comment, the problem is with blockchain.info's wallet 
rather than with the keys in the Wallet.  All four of my keys imported 
perfectly into Mt, Gox' wallet with no problems, so the directions I linked 
above do work.

Original comment by danbowk...@gmail.com on 26 Mar 2012 at 11:42

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For small amounts of money, using the Android backup service would be a good 
start. It's free and integrated since Donut, I think.

The restore case is a pain, but a new install of Bitcoin Wallet will need to 
resync the entire chain anyway, so just clearing the restored wallet of 
transactions and letting it sync normally should do the trick.

Original comment by hearn@google.com on 2 Jul 2012 at 12:20

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The Android backup service is dangerous, because according to a Google 
developer advocate they overwrite each other if you use them on multiple 
devices.

Also, remember that there is currently no safe way to reset the block chain. So 
restore would be impossible or at least very unreliable.

I'd rather do backup right.

Original comment by andreas....@gmail.com on 2 Jul 2012 at 2:37

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why not concatenate some user id (gmail account might work since this is 
android), with their passphrase, SHA-256 the string and call that the 
encryption/decryption key 

Original comment by alex.schoof on 2 Aug 2012 at 12:34

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Version 2.3 RC implements import and export of private keys to external 
storage. Would you help testing?

http://code.google.com/p/bitcoin-wallet/downloads/list

Original comment by andreas....@gmail.com on 11 Oct 2012 at 8:53

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Released as version 2.31.

Original comment by andreas....@gmail.com on 29 Oct 2012 at 2:08

• Changed state: Fixed

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Issue 66 has been merged into this issue.

Original comment by andreas....@gmail.com on 17 Oct 2013 at 9:47