Thread: Sony PRS-600 gets first firmware upgrade
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Old 09-09-2009, 06:38 PM   #22
igorsk
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Posts: 3,442
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Join Date: Sep 2006
Location: Belgium
Device: PRS-500/505/700, Kindle, Cybook Gen3, Words Gear
Quote:
Originally Posted by RyeBrye View Post
What makes you say they are encrypted? I see a checksum file with insanely large hashes, and I see the raw images. I haven't delved into it much further.

What encryption mechanism are they using?
The hash is not new, it was already used in the first firmware update for PRS-500. It's an RSA signature checked at device side against a hardcoded public key. However, the firmware images themselves (cramfs.Rootfs.img) were not encrypted; you could see "Compressed ROMFS" text in the binary.
We don't know what they use for PRS-600, I suspect some AES variant.
The firmware updater code is Sony's own, not GPL, so it's not included in the public sources.
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