diff --git a/tls-extra.cabal b/tls-extra.cabal
index bcec42c..211a967 100644
--- a/tls-extra.cabal
+++ b/tls-extra.cabal
@@ -29,6 +29,7 @@ Library
                    , crypto-api >= 0.5
                    , cryptocipher >= 0.3.0 && < 0.4.0
                    , certificate >= 1.2.0 && < 1.3.0
+                   , pem >= 0.1.0 && < 0.2.0
                    , text >= 0.5 && < 1.0
                    , time
   Exposed-modules:   Network.TLS.Extra