Verify the current region between START and END.
Don't use this command in Lisp programs!
Since this function operates on regions, it does some tricks such
as coding-system detection and unibyte/multibyte conversion. If
you are sure how the data in the region should be treated, you
should consider using the string based counterpart
`epg-verify-string', or the file based counterpart
`epg-verify-file' instead.
For example:
(let ((context (epg-make-context 'OpenPGP)))
(decode-coding-string
(epg-verify-string context (buffer-substring start end))
'utf-8))
(fn START END)