https://wiki.luatex.org/index.php?action=history&feed=atom&title=Encrypt_your_document_using_ROT13Encrypt your document using ROT13 - Revision history2026-05-21T18:19:17ZRevision history for this page on the wikiMediaWiki 1.31.1https://wiki.luatex.org/index.php?title=Encrypt_your_document_using_ROT13&diff=29&oldid=prevPatrick: Copied from the old bluwiki.com luatex wiki2010-12-07T21:19:47Z<p>Copied from the old bluwiki.com luatex wiki</p>
<p><b>New page</b></p><div>The following PlainTeX code example uses the ligaturing callback to "encrypt" the document using ROT13-"encryption".<br />
<br />
<br />
%&luatex<br />
<br />
% Notes:<br />
% <br />
% - Hyphenation is applied before rotating.<br />
% - Ligaturing is performed after rotating.<br />
<br />
\pdfoutput=1<br />
\begingroup<br />
\catcode`\%=12<br />
\directlua0{<br />
callback.register('ligaturing', function(head)<br />
for v in node.traverse_id(33, head) do<br />
if v.subtype == 1 then<br />
local c = v.char<br />
if c >= 65 and c <= 90 then<br />
v.char = (c - 65 + 13) % 26 + 65<br />
elseif c >= 97 and c <= 122 then<br />
v.char = (c - 97 + 13) % 26 + 97<br />
end<br />
end<br />
end<br />
node.ligaturing(head)<br />
end)<br />
}<br />
\endgroup<br />
<br />
% Hello World; fi -- fl -- ffl -- ffi -- enough with the ligatures!<br />
% Better do some kerning instead: AV<br />
<br />
Uryyb Jbeyq; sv -- sy -- ssy -- ssv -- rabhtu jvgu gur yvtngherf!<br />
Orggre qb fbzr xreavat vafgrnq: NI<br />
<br />
<br />
\bye</div>Patrick