Openvas Erroneous or missing signature for checksums file (null)

My exp.nasl

insstr("aaaaaaaaaaa", "bb", 3, 0xfffffffd);

run code

$sudo openvas-nasl ali.nasl

I get this error when I run exp.nasl with openvas

base gpgme-Message: Setting GnuPG dir to '/etc/openvas/gnupg'
base gpgme-Message: Using OpenPGP engine version '2.1.11'
Erroneous or missing signature for checksums file (null)

You need to specify the -X flag to openvas-nasl if you don't have a valid signature for your file:

openvas-nasl -X ali.nasl

See openvas-nasl --help and/or man openvas-nasl for a description of this and other existing flags.