Bremermann's limit

Etymology
Named after (1926–1996), German-American mathematician and biophysicist.

Proper noun

 * 1) The maximum computational speed of a self-contained system in the material universe, derived from Einstein's mass-energy equivalency and the Heisenberg uncertainty principle: it is approximately 1.36 × 1050 bits per second per kilogram. This value is important in designing cryptographic algorithms that can never be cracked by brute force.