private key rebuilding from scratch

[jubalix]

I am confused

I thought that if I had private key for btc address 11ABpUEFZLoTJLhWZAublahblah say in a blockchain.wallet info

I could put the private address into my local bt-qt client and rebuild my wallet from scratch without and wallet.dat

OR

I could get the private key from my bt-qt, and use that to build my wallet from scratch on aother computer


BUT after reading those two guys who lost 9K bitconts and around 7K respectively

it seems a whole bundle of btc address are created that you never really see....and the private key you get is just the one for the original transaction.

so as it seems when you send money all you balance is sent but then returned except for the spend bit, it is retuend to a different address in your wallet that you do not have the priv key for!!!


I tried to rebuild my blockchain.wallet in my local 0.8.0 bt-qt and it appeared to work.....


but I am not sure any more....

please help!

[DannyHamilton]

Electrum uses a deterministic algorithm for address generation (I'm not sure if MultiBit does).  Bitcoin-Qt and Blockchain.info do not.  They use random keys.

This means that if you have the seed for an Electrum wallet you can rebuild the entire wallet from the one seed.

However, if you have a private key from blockchain.info/wallet or Bitcoin-Qt, you can ONLY rebuild the one specific address that is generated from that key (and any unspent outputs for that address).  If you are using blockchain.info/wallet of BitCoin-Qt, then you need to make regular backups of the entire wallet (or at least of ALL the private keys in the wallet).  With blockchain.info, you need to create a new backup at least anytime you create a new address.  With Bitcoin-Qt, a new address (hidden from your view) is created every time you create a transaction to send bitcoins as well as every time you request a new address in the "receive coins" tab.  You need to create a new backup at least before 100 addresses are used.

[Atruk]

Electrum uses a deterministic algorithm for address generation (I'm not sure if MultiBit does).  Bitcoin-Qt and Blockchain.info do not.  They use random keys.

This means that if you have the seed for an Electrum wallet you can rebuild the entire wallet from the one seed.

However, if you have a private key from blockchain.info/wallet or Bitcoin-Qt, you can ONLY rebuild the one specific address that is generated from that key (and any unspent outputs for that address).  If you are using blockchain.info/wallet of BitCoin-Qt, then you need to make regular backups of the entire wallet (or at least of ALL the private keys in the wallet).  With blockchain.info, you need to create a new backup at least anytime you create a new address.  With blockchain.info, a new address (hidden from your view) is created every time you create a transaction to send bitcoins as well as every time you request a new address in the "receive coins" tab.  You need to create a new backup at least before 100 addresses are used.

Multibit doesn't yet have deterministic wallets, but it tends to be good about returning change to the sending address.

[ryanAC]

so as it seems when you send money all you balance is sent but then returned except for the spend bit, it is retuend to a different address in your wallet that you do not have the priv key for!!!

You have the private keys for all your 'change' addresses.  You just need to go into the console and dump them.

[DannyHamilton]

so as it seems when you send money all you balance is sent but then returned except for the spend bit, it is retuend to a different address in your wallet that you do not have the priv key for!!!

You have the private keys for all your 'change' addresses.  You just need to go into the console and dump them.

Actually, if I understood what the OP is saying correctly, they are using blockchain.info/wallet, so they don't have any 'change' addresses, and they don't have a console for dumping them.  I believe the 9k and 7k losses they were reading about were probably from users who were using Bitcoin-Qt and who didn't know that Bitcoin-Qt created its own 'change' addresses.

[jubalix]

Electrum uses a deterministic algorithm for address generation (I'm not sure if MultiBit does).  Bitcoin-Qt and Blockchain.info do not.  They use random keys.
.....>>> With blockchain.info, a new address (hidden from your view) is created every time you create a transaction to send bitcoins as well as every time you request a new address in the "receive coins" tab.  You need to create a new backup at least before 100 addresses are used.

[1] ? so block chain.info creates new address all the time?? how do I get the private keyy for these??? how do I dump them

[2] what happens after 100 in block chain info???

also

so as it seems when you send money all you balance is sent but then returned except for the spend bit, it is retuend to a different address in your wallet that you do not have the priv key for!!!

You have the private keys for all your 'change' addresses.  You just need to go into the console and dump them.

Actually, if I understood what the OP is saying correctly, they are using blockchain.info/wallet, so they don't have any 'change' addresses, and they don't have a console for dumping them.  I believe the 9k and 7k losses they were reading about were probably from users who were using Bitcoin-Qt and who didn't know that Bitcoin-Qt created its own 'change' addresses.

Actually, if I understood what the OP is saying correctly, they are using blockchain.info/wallet, so they don't have any 'change' addresses, and they don't have a console for dumping them.  I believe the 9k and 7k losses they were reading about were probably from users who were using Bitcoin-Qt and who didn't know that Bitcoin-Qt created its own 'change' addresses.


[3]...>>>this seems to indicate blockchaininfo wallet send the money back to the single address?? or does it send back to a temporary address and then send the whole amount back to the original address???

[4] I don't understand why Bt-qt doesn tensure that the whole amount goes to the origonal address???

[DannyHamilton]

[1] ? so block chain.info creates new address all the time?? how do I get the private keyy for these??? how do I dump them

Oops, sorry about causing confusion there.  That was supposed to say "With Bitcoin-Qt, a new address (hidden from your view) is created every time you create a transaction to send bitcoins as well as every time you request a new address in the "receive coins" tab."  I've fixed it in my post.

Actually, if I understood what the OP is saying correctly, they are using blockchain.info/wallet, so they don't have any 'change' addresses, and they don't have a console for dumping them.  I believe the 9k and 7k losses they were reading about were probably from users who were using Bitcoin-Qt and who didn't know that Bitcoin-Qt created its own 'change' addresses.

[3]...>>>this seems to indicate blockchaininfo wallet send the money back to the single address?? or does it send back to a temporary address and then send the whole amount back to the original address???

Yes, as I just pointed out, I meant to say that Bitcoin-Qt uses a new address every time.  blockchain.info sends back to the single address.  No temporary address, just back to the original.

[4] I don't understand why Bt-qt doesn tensure that the whole amount goes to the origonal address???

Bitcoin-Qt uses a new address for every transaction for increased security and anonymity.  It is generally recommended that you never re-use any address.  The recommendation is that you generate a brand new address for each transaction every time you receive bitcoins.  In addition Bitcoin-Qt automatically takes care of generating a new address for you every time you send transactions.  If you do not require or desire this behavior, then it is best not to use the Bitcoin-Qt wallet.