# Tag Info

There is no need to go beyond 256 bits if the cypher is strong (can only be attacked by brute force). This is because there are fundamental physical limits on the energy required to perform a computation. The Landauer limit is one: to switch one bit takes $kT\ln2$, where $k$ is the Boltzmann constant ($1.68\times10^{-23}$), $T$ is the temperature in ...