Aurora Complexus wrote on Oct 24
th, 2024 at 9:08pm:
Bobby. wrote on Oct 24
th, 2024 at 8:53pm:
Setanta wrote on Oct 24
th, 2024 at 8:42pm:
Software in the sense of what operating system you run or what programs you run on it are not the issue. It's the hardware code and what
Microcode provides. That's correct but we are talking about an unknown instruction set -
well - known only to the CPU designers and the NSA and their co-conspirators.
I suppose it's possible that the instruction set could be 128 bits wide. But if so, it would slow the processor down to have to read 128 bits for every instruction (and bear in mind that instructions are sometimes passed from one part of the processor to the other.) Even assuming the other hardware passed such an instruction, the obvious action would be to cull the top 64 bits.
But even assuming that 128 bit instructions somehow get to the processor (by a corrupted compiler) and are somehow processed to a cause a "hidden instruction" to be executed, this is still something that a hacker could detect.
They basically just have to do <crazy instruction> <input> and see if they get something other than "illegal instruction" back. Do it over and over (perhaps while they take a much needed nap.) They do that 2^32 times, or even 2^64 times, for every possible instruction.
Well maybe the "hidden instruction" requires a specific string or else it returns "illegal instruction." But remember that there is more than one hacker. A hacker may be curious enough to record the timing of every "illegal instruction" which comes back. Then they have one suspect instruction number, and can start peppering it with random strings to try to guess the "password" of that instruction. Imagine the fame they could gain, not just finding a hidden instruction but finding its password.
Quote:I suppose it's possible that the instruction set could be 128 bits wide
32 bit processing was limited to 4 G of access space. This was a restrictive limit.
64 bit processing allows what to us is unlimited addressing space.
Going to 128 bit is technically difficult - i.e. not all 64 bit processors work correctly. there have been a lot of failed processors developed. but the main reason is that to do this would be fixing a problem that does not currently exist. It would be a huge expense for something that is just not needed.
32-bit - 4,294,967,295
This is where the 4 G limit comes from.64-bit - 18,446,744,073,709,551,615
This is the number we currently use
128-bit - 340,282,366,920,938,463,463,374,607,431,768,211,455
We don't need this yet and it would cost many $ Billions possibly $ Trillions.Each step is exponential.