encryption

https://yairgadelov.me/swupdate-build-sign-install-a-minimal-.swu-that-updates-only-an-app--config/

• sw-description with image hashes is signed. New file sw-description.sig is added to container.
• public key is on device (swupdate can verify sw-description.sig).
• private key is used only internally during build of .swu bundle

SWUpdate can use PKCS provider.