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> So even if once Intel gets to be "less evil in the eyes of worried people" for a "sin" of providing RDRAND although the same people otherwise trust the compan
by ScottBurson 13y ago
> So even if once Intel gets to be "less evil in the eyes of worried people" for a "sin" of providing RDRAND although the same people otherwise trust the company to let its CPU's execute all their programs
This isn't fair. Most instructions compute deterministic functions of their operands. It's easy for people to tell if the CPU is computing the correct result. (Remember the Pentium FDIV bug?) RDRAND, by definition and design, is nondeterministic. Only by examining a long sequence of its results could one gain any confidence that it isn't backdoored ... and then one might still be overlooking something.
- agwa 13y ago> Only by examining a long sequence of its results could one gain any confidence that it isn't backdoored Actually, you can't. A properly backdoored RNG is indistinguishable from a non-backdoored RNG. Imagine a backdoored RNG that is simply a counter encrypted with AES. The output looks completely random, but it can be completely broken by the holder of the AES key.
- ScottBurson 13y agoI see. That is certainly a problem as far as our ability to ever come to trust RDRAND. But it supports the point I was making: trusting RDRAND is a very different thing from trusting the rest of the instruction set.