There literally isn't enough energy in the solar system to run a counter from 0 to 2^256. Computers may still get faster for some time, but in the absence of ne

There literally isn't enough energy in the solar system to run a counter from 0 to 2^256. Computers may still get faster for some time, but in the absence of new cryptographic weaknesses, 256 bit symmetric encryption can be considered to be safe from brute-force attacks forever. There is some trick using quantum computers that could help, but doubling the key size counters that, putting your encryption beyond the reach of brute-force once again.