diff -r -u a/src/psk.c b/src/psk.c
--- a/src/psk.c 2005-10-14 04:26:17.000000000 +0200
+++ b/src/psk.c 2009-04-27 18:10:34.000000000 +0200
@@ -24,6 +24,7 @@

 #include <openssl/hmac.h>
 #include <openssl/err.h>
+#include <openssl/sha.h>
 #include <assert.h>
 #include <string.h>