Orchid XP v7 <voi### [at] devnull> wrote:
> Warp wrote:

> >   For example the PlayStation Portable supports running programs from
> > the flash memory card directly (instead of the optical disc), but only
> > ones approved by Sony. It will refuse to run anything else.
> >   Of course in order to run them it needs to decrypt them, and to decrypt
> > them it needs a decryption key. Couldn't this key just be read from the
> > PSP's memory and use to encrypt third-party programs? The answer is: No.
> > The decryption key can be read, but it cannot be used to encrypt the
> > programs.

> Asymmetric encryption. I can see how that would work. (OTOH, couldn't 
> you just modify the firmware to not require this?)

  If the actual decryption happens in non-writable ROM memory, it would
be impossible. I don't know how it's actually done in the PSP, though.

-- 
                                                          - Warp

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