From: eichin@cygnus.com (Mark Eichin)
Date: Fri, 9 Jul 93 11:05:19 PDT
To: shipley@merde.dis.org
Subject: emacs stuff
In-Reply-To: <9307082128.AA02549@merde.dis.org>
Message-ID: <9307091804.AA03813@cygnus.com>
MIME-Version: 1.0
Content-Type: text/plain


>> ;;; * They do "ps auxww" (SunOS) on your machine while you're
>> ;;;     decrypting/signing.
	It should be possible, with pgp 2.2, to eliminate this
vulnerability.

>> ;;; * They type C-h v *pgp-passphrase* in your emacs after you've
	That's easy to clear optionally. What's hard to clear is "m-x
view-lossage" which has the raw characters. (I think emacs should have
support for safe reading and clearing, but I don't know if rms would
go for it. You'd need an excuse *other* than passwords.)

>> ;;; * They watch over your shoulder as you type it. (It's not invisible.)
	Didn't read-password or read-no-echo ever make it into an
emacs release?  Here are some ancient bits that I use. 
				_Mark_ <eichin@athena.mit.edu>
				MIT Student Information Processing Board
				Cygnus Support <eichin@cygnus.com>


;; ucbvax!brahms!weemba	Matthew P Wiener/UCB Math Dept/Berkeley CA 94720
;;; GNU Emacs library to read in passwords from the minibuffer
;;; Standard GNU copying privileges apply

(setq minibuffer-local-no-echo-map (make-keymap))

(mapcar '(lambda (x) (aset minibuffer-local-no-echo-map (car x) (cdr x)))
	(cdr minibuffer-local-map))

(let ((i ?\040))
  (while (< i ?\177)
    (aset minibuffer-local-no-echo-map i 'read-char-no-echo)
    (setq i (1+ i))))

(aset minibuffer-local-no-echo-map ?\177 'delete-char-no-echo)

;; This function squirrels each typed-in character away.
(defun read-char-no-echo () (interactive)
  (setq no-echo-list (append no-echo-list (list (this-command-keys)))))

;; This function erases the last character from the input list.
(defun delete-char-no-echo () (interactive)
  (setq no-echo-list (nreverse (cdr (nreverse no-echo-list)))))

;; This is the function the user actually uses.
(defun read-string-no-echo (prompt)
  "Get a password from the minibuffer, prompting with PROMPT."
  (let (no-echo-list)
    (read-from-minibuffer prompt nil minibuffer-local-no-echo-map)
    (mapconcat 'identity no-echo-list nil)))


;;;;;;;;;;;;;;;;;;;;;This crudity is just for demo!;;;;;;;;;;;;;;;;;;;;
(defun read-password ()
  "Prompts for a password, and doesn't echo it, stores it in 'secret'"
  (interactive)
  (setq secret (read-string-no-echo "Password: ")))


(defun shell-password ()
  "Prompts for password, no echo, and sends it to the shell"
  (interactive)
  (process-send-string (get-buffer-process (current-buffer)) 
		       (concat
			(read-string-no-echo "Password: ")
			"\n")))