> almost impossible for even a super computer "Almost" impossible is a stretch. It's regarded as impractical regardless of computational power or other available resources with current computational technology. We might as well not even try. > Decrypting a single 256-bit encrypted message would take hundreds of years, Yadav said. That's an interesting way to phrase it.
If you were in possession of an ideal computer, that floats in space and uses only the minimum energy required by physics to distinguish two states, and you were able to convert all the mass in our solar system directly into energy (which you probably wouldn't want to do, for obvious reasons) and feed that energy into the ideal computer, then you would be able to count (no decryption attempts here, just counting) all the way up to 2^231.
Trying to brute-force 256-bit keys is a very unrewarding activity indeed. If Yadav thinks he would be able to do it in "hundreds of years" rather than "long after all the stars have died" he must have a computer hidden somewhere that would run Crysis very smoothly even with all the settings on maximum.