diff --git a/apps/genpkey.c b/apps/genpkey.c
index 7f70a6b..f4c8f92 100644
--- a/apps/genpkey.c
+++ b/apps/genpkey.c
@@ -74,6 +74,7 @@
     OSSL_LIB_CTX *libctx = app_get0_libctx();
     STACK_OF(OPENSSL_STRING) *keyopt = NULL;
 
+    opt_set_unknown_name("cipher");
     prog = opt_init(argc, argv, genpkey_options);
     keyopt = sk_OPENSSL_STRING_new_null();
     if (keyopt == NULL)