No problem at all. My suggestion to verify the text clipping directly sent you down the wrong path because GPG/PGP needs to be fed a single stream of characters, and it will validate based on that single stream of characters. If you feed it something with extra gubbins in it -- especially something like a text clipping file, where the actual data are stored in the resource fork/extended attributes -- then it may not even be able to find the signature in the first place, let alone verify it. It's somewhat analogous to trying to validate a Bitcoin signature of a piece of text by looking at a piece of HTML which will display the text: yes, the original text is in there, but the signature is only valid for the text itself, not for the text + HTML gubbins.