Category Archives: Reverse Engineering

Brainstorming and case studies relating to craft of software reverse engineering.

Legal Threat #00001

Party! Do you have any idea how long I have been involved in multimedia hacking and reverse engineering? About 5 years now. All that while, folks have warned me sternly, and constantly, that this type of work would get me sued to death. I am pleased to announce that today I received my first legal threat. I feel that my work has finally been validated!

Well, it was not necessarily a legal threat, like those notorious “nastygram” cease & desist letters. It was more like a veiled reference to a possible future legal threat. Someone identifying himself as the assistant general counsel for On2 said that the company took exception to the fact that I was posting decompilations of their Java decoder.

And just when I was starting to feel that no one cared about my work…

Naturally, this raises some pressing questions. First and foremost, why was I contacted by the assistant general counsel? Why doesn’t my case warrant the attention of the lead/primary/head general counsel? Maybe if I went after their latest generation codec, VP7, my actions would merit an escalation.

For the time being, I have decided to not post the Java decompilations on my Practical Reverse Engineering site. This entire site is partially an experiment to test where the limits are. Looks like we found one such limit.

I never had a compelling reason to research legal options surrounding these RE activities. Maybe it is time to start. But I am just so lazy… As always, this subject may be revisited. Feel free to email me regarding this situation.

VP5 Progress In The Distributed Arena

I am pleased to report that people have been jumping on the decompiled Java-based VP5 decoder. Notably, it was clear to one individual that the method called clinch() that read bits from the stream using some bizarre algorithm is, in fact, an arithmetic decoding algorithm.

Regarding credits: I realize that many people engaged in reverse engineering activities are a little paranoid about having their achievements recognized. As such, my default policy is to not mention a contributor’s name unless they specifically ask for credit.

This is the current version of the decompiled VP5 Java cryptogram. Updates may occur at any time so check on the version number and timestamp inserted by SVN.