[sldev] Cache politics: performance vs obfuscation

[Argent Stonecutter]

On 2008-06-12, at 04:18, Jason Giglio wrote:
> Pre-pending the NUL character, ASCII 0, onto the beginning of file  
> will
> prevent it from being recognized as valid by pretty much everything.

Um, Jason, I already proposed simply prepending the metadata to the  
file for that purpose. Yes, the additional XOR step is not much  
additional security. We all know that. Storing the data in internal  
format instead of a standard file format is a more important part...  
both for obscurity and for efficiency. The xor step is free, though,  
since it is just as fast as a simple block copy on any modern  
processor, and you need to do that copy anyway unless you're  
obsessively careful with alignment.

> I tested it, it works.  Nothing could open a jpg that I prepended  
> ASCII
> 0 onto the beginning of.

I think "dd bs=1 skip=1" is probably insufficiently obscure.