Please help - New to Bitcoin, lost passphrase!

[exodus-bitcoin]

Hi all, relatively new to the forum and I think it is only possible for me to post in this section at present.

Experiencing some difficulties unfortunately! Really hoping someone maybe kind enough to offer some advice. I'll try and describe my situation as best as possible. New to the whole Bitcoin thing. I had a Bitcoin account setup on my PC running Windows 7. Made a backup of my wallet.dat which i have safe. This backup was made before I encrypted the wallet I'm pretty sure. Unfortunately I clicked the encrypt wallet a few weeks/months ago set a passphrase but didn't back it up again at this point I don't think.

I am in the terribly embarrassing situation of having forgotten my passphrase. I know roughly the letters and characters I used, but have tried repeatedly to find it but no luck! I was sure I had recorded it somewhere have searched the house but still to no avail.

I tried renaming my wallet.dat to another name and restoring a backup of my original wallet.dat (before encryption) it loads the wallet but there is no bitcoins showing in there and the transaction history doesn't make sense (I don't recognise what is there)! I think i may have lost my Bitcoins

Any help would be really appreciated. I'm sorry there was only about 5 bitcoins in the wallet, so can't really pay anyone a substantial amount to help me. Its more a matter of principal now! 

 

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[Motoma]

Your Bitcoin wallet contains a list of transactions that you have performed. If you restored an old wallet, your newer transactions can be missing.

What you will want to do is shutdown the Bitcoin client, restore your old wallet.dat file, and delete the block chain files (blk*.dat). When you restart Bitcoin, it will need to download the entire block chain again, but when it finishes, you will have all your transactions back and your balance will be correct.

Cheers,
Motoma

[exodus-bitcoin]

Hi Motoma and thanks very much for your reply. I had not deleted any of the block chain files so I will try this now and see what the result is. Thanks once again for your help. I will reply back if I am successful or not.

[Raoul Duke]

With the backup wallet restored, go to the debug window RPC console, type -rescan and press enter.
See if any bitcoins show up.

If the wallet.dat backup is old you may have a problem, as encryption of the file will flush your change addresses pool and create new addresses, so, any transaction you sent after the encryption, and that transaction had change, the change won't be on that backup for sure.

[DannyHamilton]

. . . I am in the terribly embarrassing situation of having forgotten my passphrase. I know roughly the letters and characters I used, but have tried repeatedly to find it but no luck! I was sure I had recorded it somewhere have searched the house but still to no avail . . .

Depending on the length and complexity of your password (and how much of it you remember), there may be some scripts that can be run that can attempt to brute force your password by repeatedly trying all possible variations until it encounters the correct one.

[exodus-bitcoin]

Hi psy thanks for your reply. I seem to have the exact problem you mention as I am in my wallet and I can see the 2 incoming transactions of 1 and 9 bitcoin from when i set up my bitcoin wallet. This is correct as somebody transferred 10 bitcoins to me originally in that exact format, 1 bitcoin as a test I had it setup ok and could receive bitcoin, then sent me the other 9 once i confirmed everything was ok.
Like you say though I had made a transaction since that outgoing but it is showing as the full 9 bitcoin had been transferred out when I only transferred 4!
Is it that this 5 bitcoin is permanently lost now? I have a copy of my encrypted wallet.dat that I do not know passphrase for. Is it possible me to brute force exploit/crack this in any way as I know roughly what letters and numbers I used when i set the passphrase just cannot remember correct combination. Have tried so many times.
I know it seems a lot of hassle over 5 bitcoin (£40), it is just I do not like to lose money (of any currency)!  

[exodus-bitcoin]

. . . I am in the terribly embarrassing situation of having forgotten my passphrase. I know roughly the letters and characters I used, but have tried repeatedly to find it but no luck! I was sure I had recorded it somewhere have searched the house but still to no avail . . .

Depending on the length and complexity of your password (and how much of it you remember), there may be some scripts that can be run that can attempt to brute force your password by repeatedly trying all possible variations until it encounters the correct one.

Hi DannyHamilton. Sorry I just saw your reply after making my last post. Yes this is exactly my line of thinking. I did see a thread in here on another section which was about a similar thing. I believe my password would have been around 10-12 characters total. I know the words and numbers that I would have used but cannot remember combination!
I have limited knowledge in this area unfortunately and I could not understand howto implement and execute such a thing in windows. Would likely need some sort of 'idiots guide' (the idiot being me of course)
 

[DannyHamilton]

I'd suggest contacting either riX or Revalin from this discussion:

https://bitcointalk.org/index.php?topic=85495.msg942171#msg942171

They both seem to have the skills necessary to assist you and have demonstrated a willingness to help others with similar issues in the past.

[Raoul Duke]

Hi psy thanks for your reply. I seem to have the exact problem you mention as I am in my wallet and I can see the 2 incoming transactions of 1 and 9 bitcoin from when i set up my bitcoin wallet. This is correct as somebody transferred 10 bitcoins to me originally in that exact format, 1 bitcoin as a test I had it setup ok and could receive bitcoin, then sent me the other 9 once i confirmed everything was ok.
Like you say though I had made a transaction since that outgoing but it is showing as the full 9 bitcoin had been transferred out when I only transferred 4!
Is it that this 5 bitcoin is permanently lost now? I have a copy of my encrypted wallet.dat that I do not know passphrase for. Is it possible me to brute force exploit/crack this in any way as I know roughly what letters and numbers I used when i set the passphrase just cannot remember correct combination. Have tried so many times.
I know it seems a lot of hassle over 5 bitcoin (£40), it is just I do not like to lose money (of any currency)!  

You sent 4 Bitcoins to one address, but if your client chose the 9BTC transaction to send those 4 it would then send the remaining 5 BTC to one of your change addresses, which unfortunately for you, only exist on the encrypted wallet

[exodus-bitcoin]

Hi psy thanks for your reply. I seem to have the exact problem you mention as I am in my wallet and I can see the 2 incoming transactions of 1 and 9 bitcoin from when i set up my bitcoin wallet. This is correct as somebody transferred 10 bitcoins to me originally in that exact format, 1 bitcoin as a test I had it setup ok and could receive bitcoin, then sent me the other 9 once i confirmed everything was ok.
Like you say though I had made a transaction since that outgoing but it is showing as the full 9 bitcoin had been transferred out when I only transferred 4!
Is it that this 5 bitcoin is permanently lost now? I have a copy of my encrypted wallet.dat that I do not know passphrase for. Is it possible me to brute force exploit/crack this in any way as I know roughly what letters and numbers I used when i set the passphrase just cannot remember correct combination. Have tried so many times.
I know it seems a lot of hassle over 5 bitcoin (£40), it is just I do not like to lose money (of any currency)!   

You sent 4 Bitcoins to one address, but if your client chose the 9BTC transaction to send those 4 it would then send the remaining 5 BTC to one of your change addresses, which unfortunately for you, only exist on the encrypted wallet

Yes this makes perfect sense as there was 1 BC showing in the account when I loaded backup instead of the 5 that should have been there. As you state the 1 bitcoin would have been the independent 'tester' transaction. So it is the 'change' I have lost form the 9 bitcoin transaction. So it seems the only way possible to recover the 5 bitcoin change is to remember (I wish!) or crack the encrypted password.

I am cursing my utter stupidity to have lost such a thing. I was sure I thought I knew what it was but have tried it so many times now and still no joy.

Unless I can crack this passphrase I think maybe I have to give up and start again!

[riX]

unless you did 100+ transactions the change address should be in the unencrypted wallet.

[DannyHamilton]

unless you did 100+ transactions the change address should be in the unencrypted wallet.

I don't believe this is true.

It is my understanding that when you encrypt an unencrypted wallet, it tosses out the pool of 100 pre-generated addresses and generates a new pool of 100 addresses after encryption.

This means that the change address used by the encrypted wallet was generated after encryption and is not available in the unencrypted wallet.

As such, his only chance at recovering these bitcoins is to find a way to brute-force the password based off the parts of the password he can remember.

[riX]

unless you did 100+ transactions the change address should be in the unencrypted wallet.

I don't believe this is true.

It is my understanding that when you encrypt an unencrypted wallet, it tosses out the pool of 100 pre-generated addresses and generates a new pool of 100 addresses after encryption.

This means that the change address used by the encrypted wallet was generated after encryption and is not available in the unencrypted wallet.

As such, his only chance at recovering these bitcoins is to find a way to brute-force the password based off the parts of the password he can remember.

Ok, I don't know, it's probably true.
But it might be worth checking anyway unless you're sure, it should not really be any more unsafe to just encrypt the original change addresses, since the ones used in transactions are saved.

[DannyHamilton]

unless you did 100+ transactions the change address should be in the unencrypted wallet.

. . . when you encrypt an unencrypted wallet, it tosses out the pool of 100 pre-generated addresses and generates a new pool of 100 addresses after encryption . . .

. . . it might be worth checking anyway unless you're sure . . .

I'm sure:

https://github.com/bitcoin/bitcoin/blob/0f8a6477825fbaad0d37233bdd3011d748f607ab/src/wallet.cpp

bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
{
. . .
        NewKeyPool();
. . .
}

//
// Mark old keypool keys as used,
// and generate all new keys
//
bool CWallet::NewKeyPool()
{
. . .
        BOOST_FOREACH(int64 nIndex, setKeyPool)
            walletdb.ErasePool(nIndex);
. . .
        for (int i = 0; i < nKeys; i++)
        {
            int64 nIndex = i+1;
            walletdb.WritePool(nIndex, CKeyPool(GenerateNewKey()));
            setKeyPool.insert(nIndex);
        }
. . .
}