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It's not checkmate. It's a completely unreasonable threat model. How would the processor know where the entropy pool used by the operating system is? How would
by ars_technician 13y ago
It's not checkmate. It's a completely unreasonable threat model. How would the processor know where the entropy pool used by the operating system is?
How would the processor even know it's performing crypto operations that it should swap numbers for?
- tedunangst 13y agoPresumably using the same skynet tech it uses to look ahead and see where the rdrand is going to be xored into. I'm less familiar with precisely how linux does it, but it's not as simple as "newsecret = oldsecret ^ rdrand". The bits are scattered all to hell. Building a "where will this rdrand go?" backdoor is harder than building a backdoor that just trawls through load addresses for various common kernels looking for the symbol table so it can poison the entropy directly.
- ars_technician 13y agoDo you realize how much of a performance hit modern desktops would take if a processor that had to freeze the operating system while it wandered through memory first identifying the operating system and then finding the entropy pool and modifying it? >Presumably using the same skynet tech it uses to look ahead and see where the rdrand is going to be xored into. There is no such tech. That's why this is not 'checkmate'. A poisoned random number that generates numbers in a predictable manner is orders of magnitude easier to implement and less possible to detect than a magical processor that changes memory it thinks might be entropy for some operating systems it has been pre-programmed to look for under the assumption that kernel will never change ever. Get real.
- tedunangst 13y agoI think you have misinterpreted my comments as arguments for the backdoor that I am attempting to dismiss.