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Comment by ammar2 | Hacker News Reader

Not sure if it opens up that much on them as far as their security processors go. Modern consoles already treat DRAM as completely untrusted (an attacker could just sit on the DRAM bus and sniff/issue requests there).

The Xbox One for example encrypts all the DRAM it uses after it gets out of the main CPU die. See this part of Tony Chen's presentation https://youtu.be/U7VwtOrwceo?t=956

Also see this bit on the Apple Secure Enclave in the "Memory Protection Engine" section which also explains how they encrypt stuff stored in DRAM: https://support.apple.com/guide/security/the-secure-enclave-...

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In the README it talks about accessing and modifying the code of the Platform Security Processor including accessing the keys, how is what is on an Xbox different?

The Xbox does not use AMD's Platform Security Processor, they have their own custom controller on die with Microsoft hardware and their own custom BootROM. This custom security processor actually has its own bit of RAM entirely in the die and doesn't even go out to the DRAM at all.

See the slide on Tony Chen's presentation about Xbox One security https://youtu.be/U7VwtOrwceo?t=843 and this video from the person who hacked the Xbox One https://youtu.be/FTFn4UZsA5U?t=299

But the million dollar question is, do they rotate the IV per block or do they opt for speed as AMD and Intel both did by deriving it from the address and thus are vulnerable to someone sniffing the bus? (Note that older Intel server hardware wasn't vulnerable in this way but tracking IVs slowed everything down so they did away with it.)

wouldn't request after DRAM controller be unencrypted ? Would need to have different key per memory type and even then you could do some damage as realistically it won't have number of keys equal to running processes

Modern server CPUs have different memory encryption keys per VM, it's how AWS Nitro Secure Enclaves can work.

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