A serious bug was been found in the "encrypt wallet" function of bitcoin versions 0.4 and 0.5: private keys may be left unencrypted in the wallet.dat file after encryption.
If your encrypted 0.4 wallet file is stolen, an attacker may be able to recover some or all of your private keys and steal some or all of your bitcoins.
The development team has been working on fixes for bitcoin versions 0.4 and 0.5, but it will take at least a few days to test them thoroughly. Until they are available, you should assume that your 'encrypted' wallets are as vulnerable as an unencrypted wallet, and follow all the best practices for keeping them safe (see
here for a list).
It is embarrassing and astonishing that this critical a bug was not caught before the 0.4 release; constructive suggestions on how to improve the testing and release processes that do not assume access to hundreds of thousands of dollars of funds to hire security consultants or QA teams are welcome. Getting sufficient testing of code BEFORE it is released has been a chronic problem for this project.
Hi Gavin.
I just saw this post of yours! I happen to have found an old wallet of mine which I lost the password to to which I think was created with version 0.4 or 0.5
So I have a question: How could I search for these unencrypted private keys in my hex editor? Would they have the 0420 byte prefix? OR are they in some other format? How do they appear? Many thanks in advance.
