Changing the hashes? Not so easy.

1) Every commit includes references to the corresponding state of its file tree, as well as its parent commit(s). Change any of the files or the parent hashes, and suddenly the child commit becomes an orphan, or fails to find its file tree. Unless you hack the child commit as well. And then you have to hack its children, and so on, right down through the entire repository. You can’t just tell one lie, you have to tell a whole lot of lies.

2) Git is a distributed version-control system. That means that everybody has their own copy of the entire repository. You may be able to change one copy, but how do you hack into everybody’s machines to change them all? But if one is changed and another is not, then you’re going to set off alarm bells as soon as somebody tries to pull or push patches between them, and finds it failing because things that are supposed to match up, don’t.

@Lawrence D'Oliveiro so all you have to do is get access to the system and change the hash according to your changes to the code, that's not so impossible is it?

This is why Git attaches an SHA-1 hash to every single object in the repository. Change one bit of any object, and the SHA-1 hash will no longer be the same. But every object is referred to by its hash. So if the hash doesn’t match, you’re going to get pretty obvious errors trying to follow those references, and you’ll notice that something is wrong.

Which is not to say you can’t fake history with Git (it even provides the tools to make it easy), but you cannot hide the fact that you have done so.

Source code (IP) "...the crown jewels". Ummm, news flash - this code, like most, probably was outsourced a couple times over. The crown jewels of America were already and continue to be silently (and knowingly) pissed away everyday.

I've no sympathy for anyone who uses IE, certainly not any corporate IT that does. Merely click on a link to an infected website, and there goes all your other protections.

CNN reports that an Atlanta-based company is saying the Chinese Google hack was done by amateurs on a low budget:

http://edition.cnn.com/2010/BUSINESS/03/03/china.google.study/

Your data is save in the cloud.