Hiding information in the font tables. Run make to see an example, or view this document. Try to copy and paste the text to see the steganography in action.
Requires much of the core tex and pdflatex, pf2afm, afm2tfm, tftopl, t1disasm, t1asm to modify fonts.
First presented at DC Hack && Tell Round 28: The Cloverfield Ultimatum.