diff --git a/doc/design-paper/blocking.html b/doc/design-paper/blocking.html
index 556be3295165986e5a5be0a765c65f32330d3585..6028f5dc1c24e5b12a8e9319cee6ced0be8ef778 100644
--- a/doc/design-paper/blocking.html
+++ b/doc/design-paper/blocking.html
@@ -1393,7 +1393,7 @@ in the face of an adversary with limited resources.
 <div class="p"><!----></div>
 Many people speculate that installing and using a Tor client in areas with
 particularly extreme firewalls is a high risk &mdash; and the risk increases
-as the firewall gets more restrictive. This notion certain has merit, but
+as the firewall gets more restrictive. This notion certainly has merit, but
 there's
 a counter pressure as well: as the firewall gets more restrictive, more
 ordinary people behind it end up using Tor for more mainstream activities,
diff --git a/doc/design-paper/blocking.tex b/doc/design-paper/blocking.tex
index c05df692c36d4ce88be7b8079ed3f134202fa9d9..3b7d05ca57fdf31ba10c6f5b45ab6a49d3ea76ac 100644
--- a/doc/design-paper/blocking.tex
+++ b/doc/design-paper/blocking.tex
@@ -1318,7 +1318,7 @@ in the face of an adversary with limited resources.
 
 Many people speculate that installing and using a Tor client in areas with
 particularly extreme firewalls is a high risk---and the risk increases
-as the firewall gets more restrictive. This notion certain has merit, but
+as the firewall gets more restrictive. This notion certainly has merit, but
 there's
 a counter pressure as well: as the firewall gets more restrictive, more
 ordinary people behind it end up using Tor for more mainstream activities,