This comment extends further into the realm of speculation than the original post. The article doesn't even mention Apple's understanding of encryption, let alone specifics like algorithms and key sizes.
The post only speculates about the meaning of Apple's carefully worded feature description, the scope of the device encryption, and whether it's primary intent is to enable the remote wipe feature.
With regard to four digit pins - the strength and length of a password is hardly immaterial to security if it is being used to derive or encrypt the key. This is especially true if the wipe needs to be triggered remotely. Storage of the key on the network or MobileMe would present a host of other issues that I suspect Apple would want to stay away from.
Yes, it is more speculative, but I have lower standards for HN comments than HN submissions.
The article doesn't mention Apple's understanding of encryption, but it seemed to speculate that this encryption wouldn't be "real" encryption: "is it really securing the device while running".
As for the length of the pin, it isn't as important as you think. Assuming the attacker doesn't read the compact flash directly (there is very little you can do at that point), you can store a strong encryption key on disk and protect the device via an exponentially increasing lockout. If the key were also stored in iTunes, you can always wipe the key from disk and require the phone be re-sync'd.
Anyway, my point is that the original article is lame.
The post only speculates about the meaning of Apple's carefully worded feature description, the scope of the device encryption, and whether it's primary intent is to enable the remote wipe feature.
With regard to four digit pins - the strength and length of a password is hardly immaterial to security if it is being used to derive or encrypt the key. This is especially true if the wipe needs to be triggered remotely. Storage of the key on the network or MobileMe would present a host of other issues that I suspect Apple would want to stay away from.