Recover the password for the bitcoin wallet by using an unencrypted backup

[grace_monkey]

I’ve lost my password for bitcoin wallet

But I have unencrypted backup of the wallet that was made a year ago.
Unfortunately, bitcoins stored on addresses that contained only in ciphered wallet, not in unencrypted backup.
But some addresses are contained both in the encrypted and unencrypted wallet backup

I have idea:
- choose any address that contained in both the ciphered wallet and unencrypted backup
- extract private key for address from unencrypted backup
- extract ciphered private key from ciphered wallet
- compare two extracted strings and get password for the wallet

I have superficial knowledge of cryptography, but this should work

my idea is feasible?
Anyone know about software that can do what I described?
Can anyone create such software for reward?

[InceptionCoin]

Try to load you backup wallet first. Bitcoin-qt save up to 100 addressess for future using in the wallet to use in the future, so if you made less then 100 operations you are probably have all used privkeys in the old wallet.
As i know bitcoin-qt encrypt whole wallet not each address independently, so your plan probably not feasible.

[scientific]

I’ve lost my password for bitcoin wallet

But I have unencrypted backup of the wallet that was made a year ago.
Unfortunately, bitcoins stored on addresses that contained only in ciphered wallet, not in unencrypted backup.
But some addresses are contained both in the encrypted and unencrypted wallet backup

I have idea:
- choose any address that contained in both the ciphered wallet and unencrypted backup
- extract private key for address from unencrypted backup
- extract ciphered private key from ciphered wallet
- compare two extracted strings and get password for the wallet

I have superficial knowledge of cryptography, but this should work

my idea is feasible?
Anyone know about software that can do what I described?
Can anyone create such software for reward?

You can't do this anyway. Bitcoin Core uses AES. Read here: https://en.wikipedia.org/wiki/Known-plaintext_attack

[grace_monkey]

Try to load you backup wallet first. Bitcoin-qt save up to 100 addressess for future using in the wallet to use in the future, so if you made less then 100 operations you are probably have all used privkeys in the old wallet.
As i know bitcoin-qt encrypt whole wallet not each address independently, so your plan probably not feasible.

if you encrypt your wallet - bitcoin deletes all unused addresses and refills key pool

[grace_monkey]

I’ve lost my password for bitcoin wallet

But I have unencrypted backup of the wallet that was made a year ago.
Unfortunately, bitcoins stored on addresses that contained only in ciphered wallet, not in unencrypted backup.
But some addresses are contained both in the encrypted and unencrypted wallet backup

I have idea:
- choose any address that contained in both the ciphered wallet and unencrypted backup
- extract private key for address from unencrypted backup
- extract ciphered private key from ciphered wallet
- compare two extracted strings and get password for the wallet

I have superficial knowledge of cryptography, but this should work

my idea is feasible?
Anyone know about software that can do what I described?
Can anyone create such software for reward?

You can't do this anyway. Bitcoin Core uses AES. Read here: https://en.wikipedia.org/wiki/Known-plaintext_attack

Thank you! This is the answer for question