diff --git a/smtp-mail.cabal b/smtp-mail.cabal
index 88a6fba..0fc3fec 100644
--- a/smtp-mail.cabal
+++ b/smtp-mail.cabal
@@ -42,7 +42,7 @@ library
                , network
                , network-bsd
                , text
-               , crypton ^>= 1.0
+               , crypton == 0.* || ^>= 1.0
                , memory
 
   ghc-options: -Wall -fwarn-tabs