Function: epa-sign-region

Sign the current region between START and END by SIGNERS keys selected.

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 should be treated, you should consider
using the string based counterpart `epg-sign-string', or the file
based counterpart `epg-sign-file' instead.

For example:

(let ((context (epg-make-context 'OpenPGP)))
(encode-coding-string (buffer-substring start end) 'utf-8))) (fn START END SIGNERS MODE)