128 bits a reasonable bound for "nontrivial information" (information you'd never arrive at by guessing). 1664 bits is enough to write a short poem. However I

128 bits a reasonable bound for "nontrivial information" (information you'd never arrive at by guessing). 1664 bits is enough to write a short poem. However I don't think a 1664 bits is an accurate count. You must subtract the information provided by knowing it represents the alphabet, which constrains the number of possibilities to only a few choices per letter - say 2 or 3 bits at most. So a 64-character alphabet is right on the edge of "reasonably nontrivial", due entirely down to the combinatorial complexity of choosing which glyph to use in each case. A single glyph should not be copyrightable.