28-07-2026, 11:11 PM
(This post was last modified: 28-07-2026, 11:11 PM by Jorge_Stolfi.)
(28-07-2026, 10:47 PM)oshfdk wrote: You are not allowed to view links. Register or Login to view.I don't think so, any sequence of length N may contain at least lb(N) bits of information. Cue unary numeral system. Alternating 0 and 1 is lb(N) + 1, since the sequence may start with either 0 or 1.
Correct. If the length is not known in advance, it would be part of the information contents.
I wonder if people have ever used for real lengths of things etc to encrypt hidden messages within innocent or misleading ones? Like, the number of letters in each line, modulo 26, is one letter of the message? Or the length N of the paper in 1/16ths of an inch is an index into a codebook? Does Trithemius and his gang mention this possibility?
All the best, --stolfi