I have seen endless need for this answer because folks trying to use Strongswan from within Webmin, has an issue. I have been using Webmin since v 0.75, and the VPN module is the first module that has never worked. Here's Andreas' reply ten years ago: https://users.strongswan.narkive.com/IMUCTU8H/generating-rsa-digital-signature-for-ipsec-secrets I quote Andreas (the developer), "Hello Mohit, strongSwan does not actively support this clumsy FreeS/WAN / Openswan raw RSA key format anymore. You can...