diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index 5a874b3..67ac0b4 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -149,6 +149,7 @@
 
 exit:
     pk_free( &pk );
+    entropy_free( &entropy );
 
 #if defined(POLARSSL_ERROR_C)
     polarssl_strerror( ret, (char *) buf, sizeof(buf) );