add link to poly1305-design (really good)

diff --git a/src/openpower/decoder/isa/poly1305-donna.py b/src/openpower/decoder/isa/poly1305-donna.py
index 390c71b516164f070c5a99267a43b5f241a50066..bff1aa28243d614e0772ddf9f6266b01fb77c164 100644 (file)
--- a/src/openpower/decoder/isa/poly1305-donna.py
+++ b/src/openpower/decoder/isa/poly1305-donna.py
@@ -4,7 +4,10 @@
 # * https://nlnet.nl/project/LibreSOC-GigabitRouter/
 # * https://bugs.libre-soc.org/show_bug.cgi?id=1157
 # * Based on https://github.com/floodyberry/poly1305-donna (Public Domain)
-"""Implementation of Poly1305 authenticator for RFC 7539"""
+"""Implementation of Poly1305 authenticator for RFC 7539
+Design principles are well-documented at:
+https://loup-vaillant.fr/tutorials/poly1305-design
+"""
 
 def divceil(a, b): return -(a // -b)