As you can read in many many posts on these forums, decrypting without a password is not possible.
It was never possible, it is not possible, and it will never be possible.
There would be absolutely no point in encrypting stuff with a password if there is a tool to simply decrypt it without a password.
--
The password is needed since the password itself is the key to decrypt the logs.
The encryption/decryption system is not a simple "
if the password is not correct you aren't allowed to view it"-system (which can be bypassed easly), but a "
I need the correct password to know what calculations I need to do to decrypt"-system
--
Brute force attacks are possible for any any decryption/encryption system in the world...
in theory(!). That's not rocket science.
However,
in practice, a brute force attack takes an extreme lot of time, in the order of years, even decades(!), and that's even using an über-super-computer....
Even using rainbow-tables will take a lot of time, despite what some people might say. The reason is very simple: you need to calculate the rainbow tables first. Which takes the same amount of time as with brute force attackers.
A dictionary attack is nothing more than a brute force attack using only known words. In other words, if you have a password which is not an existing word, a dictionary attack will be completely useless. Even using 1 digit in your password renders almost all dictionary attacks useless.
The point is that in almost all cases you don't know what password is used; It can be an existing word, but chances are just the same that it isn't.
------------
Forgive me for saying this also, but using Messenger to communicate "very important financial information" is not smart to do. There are better, more secure ways, to do this sort of thing. Even then, if he needs this info, why don't he ask the info again from his contact he got it from, or request it in a more official way via his company.
Also, the point of a password is that you also can remember it. If you have trouble remembering passwords, either don't use them, or either write them down.
------------
In the next version of Messenger Plus! Live you will be able to set a password hint. In that way remembering a password would be somewhat easier (but less secure ofcourse). See
Patchou's reply to forgoten password from chatlog of v4.0.0.214.