diff --git a/Doc/lib/libcodecs.tex b/Doc/lib/libcodecs.tex
index 6baf188..8a2417e 100644
--- a/Doc/lib/libcodecs.tex
+++ b/Doc/lib/libcodecs.tex
@@ -1230,7 +1230,7 @@
 
 \lineiv{rot_13}
          {rot13}
-         {byte string}
+         {Unicode string}
          {Returns the Caesar-cypher encryption of the operand}
 
 \lineiv{string_escape}