diff --git a/Doc/lib/libcrypto.tex b/Doc/lib/libcrypto.tex
index ab40819..a04c849 100644
--- a/Doc/lib/libcrypto.tex
+++ b/Doc/lib/libcrypto.tex
@@ -26,6 +26,7 @@
 \url{http://www.magnet.com/\~amk/python/pct.html} or send email to
 \email{amk@magnet.com} for more information.
 \index{PGP}
+\index{Pretty Good Privacy}
 \indexii{DES}{cipher}
 \indexii{IDEA}{cipher}
 \index{cryptography}