For last last two days I've been staring blankly at my hex editor trying to make sense of the meaningless jumble of ASCII text I suspect might be the contents of the text file stored in the sample archive. In reality, it might be anything: the text I suspect, some sort of file integrity information, anything. But, right now, I'm operating under the assumption that it's the contents of the file.
I need to figure out the structure of the file and the type of encryption (if any) is used for the data it contains.. Obviously, I know the first 4 bytes of the file identifies it as a RAR archive. Right now, that's all I know as far as structure goes.
As for encryption, it's a tough job. Since I know the exact text contained in the archived file, I'm taking the time to symmetrically encrypt a file using different algorithms and then visually compare the text. Of course, there's always the chance that the text is asymmetrically encrypted to someone's key (probably either the RARLABS key or maybe even one of the developers keys). Add to that the fact that it might not even BE strong encryption. It might be some home grown soft encryption thing that's easily broken. Right now, I have no clue.
So the work continues. For the foreseeable future, unless I have a grand epiphany on encryption schemes, I'm going to be working on finding the structure of the file and the encryption scheme. That's where you'll find me, toiling the time away.