Well, yeah he forgot to mention Mail app (also runs on Mac) where you just click on Gray/Blue star "Sign" - and it's signed. But that's only the message right?

Well, yeah he forgot to mention Mail app (also runs on Mac) where you just click on Gray/Blue star "Sign" - and it's signed. But that's only the message right? Well - you should sign PDF before as well. Then - it's done. Don't get us wrong - I don't even check your project - which definitely deserve to exists - just saying - maybe it's not for everyone...