On Thursday 25 June 2009 07:22:10 Detlev Zundel wrote:
On Wednesday 24 June 2009 12:45:38 Detlev Zundel wrote:
It is secure because only authenticated code is allowed to be executed, thus another step to avoid piracy, hacking of conditional access systems etc.
Running only authenticated code does *not* ensure security, no matter how much this is wished for.
But no matter, I now understand that "security" seems to mean "data can only be handled in the way intended by the owners of the data" which is a different concept to me.
you ignored my simple straightforward example where both authenticity and security is provided. cpu only loads signed u-boot -- authenticity. u-boot only loads encrypted signed binaries -- security and authenticity. since the binaries stay inside of the CPU, for all practical (and then some) purposes, the decrypted binary will never be discovered from this system.
Obviously we differ in what "security" means. Where I used security as an attribute of a communications channel which seems to be a popular interpretation in computer science, you interpret "security" to mean "not discoverable from outside the device". The latter interpretation is used in the DRM systems trying to rub off the good annotations of "security" onto those systems - but still it is not synonymous to "security" for me.
you really should use the standard terms of the trade then, otherwise you will just keep confusing people. http://en.wikipedia.org/wiki/Information_security#Basic_principles -mike