Okay guys, just registered to post this...
Metldr (meta loader) is one of the lowest level functions of the P$3. It is a per console, unique, hardware based code... Meaning the one for your console, is only for your console. Each one has its own. I will refer to this as your 'hard key'.
Now, if you remember, back before geohot got sued, he released a set of keys, most important of which (for all your pirates out there), was the appldr (application loader) key. These are public keys, meaning that every P$3 made uses the SAME keys... This is how your P$3 decides whether the .pup (a firmware file [3.55 for example]) is genuine, or fake. These keys are decided by software, and therefore don't physically exist. This means that they can be updated whenever $ony see's fit, and is the reason modern games won't run on old firmwares.
Now, if you also cast your mind back, you'll remember that when geohot was about to get sued, he posted a comment similar to, "So no one STILL knows how I got the metldr keys????
". He mentioned this, because if the metldr encryption key is known, then the soft keys can be decrypted. If the soft keys can be decrypted you can exploit the appldr, and have all your backup managers etc, on any firmware.
What makes this metldr key so special, is that, unlike the 'soft' keys, no update can be brought out to modify your metldr key. And, so long as you always know your metldr key (which you can do now), you will ALWAYS know your 'soft' keys, which are what 99% of you are here to try and find out.
Put simply:
metldr key = soft keys = cfw
This is why it's taken so long to get past 3.55. Geohot released the 'soft' keys, using his own metldr exploit (one would imagine was very similar, if not identical to this piece of C), but never released the method with which to obtain the metldr key itself. So the soft keys released could be updated, and, as we all know they were, and the system re-secured... Now however, we have full access to decrypt the soft keys, effectively continuing where geohot left off.
I hope that this makes sense to at least a couple of you, and sheds some light as to what this means for the scene, and also why people like math and geo were so reluctant to release these exploits.
Peace...