[Cryptography] New block cipher competition

[Phillip Hallam-Baker]

2^256 is a very big number. About 10^77

Or roughly the number of atoms in the known universe
After roughly 100 trillion years, the universe runs out of gas for
stars to form naturally. If we express this in planck time we get
10^62 planck instants in the lifetime of the universe.

So if someone was being ultra, ultra cautious, one might use a key
that is 512 bits long, that being the lifetime of every atom in the
universe in plank time.