remove call to bibtex-reformat which often hangs
[org-mode/org-mode-NeilSmithlineMods.git] / lisp / org-crypt.el
blobc613ba20e484b6cb5a9655d8e73899e7684ae467
1 ;;; org-crypt.el --- Public key encryption for org-mode entries
3 ;; Copyright (C) 2007, 2009-2012 Free Software Foundation, Inc.
5 ;; Emacs Lisp Archive Entry
6 ;; Filename: org-crypt.el
7 ;; Keywords: org-mode
8 ;; Author: John Wiegley <johnw@gnu.org>
9 ;; Maintainer: Peter Jones <pjones@pmade.com>
10 ;; Description: Adds public key encryption to org-mode buffers
11 ;; URL: http://www.newartisans.com/software/emacs.html
12 ;; Compatibility: Emacs22
14 ;; This file is part of GNU Emacs.
16 ;; GNU Emacs is free software: you can redistribute it and/or modify
17 ;; it under the terms of the GNU General Public License as published by
18 ;; the Free Software Foundation, either version 3 of the License, or
19 ;; (at your option) any later version.
21 ;; GNU Emacs is distributed in the hope that it will be useful,
22 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
23 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 ;; GNU General Public License for more details.
26 ;; You should have received a copy of the GNU General Public License
27 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
29 ;;; Commentary:
31 ;; Right now this is just a set of functions to play with. It depends
32 ;; on the epg library. Here's how you would use it:
34 ;; 1. To mark an entry for encryption, tag the heading with "crypt".
35 ;; You can change the tag to any complex tag matching string by
36 ;; setting the `org-crypt-tag-matcher' variable.
38 ;; 2. Set the encryption key to use in the `org-crypt-key' variable,
39 ;; or use `M-x org-set-property' to set the property CRYPTKEY to
40 ;; any address in your public keyring. The text of the entry (but
41 ;; not its properties or headline) will be encrypted for this user.
42 ;; For them to read it, the corresponding secret key must be
43 ;; located in the secret key ring of the account where you try to
44 ;; decrypt it. This makes it possible to leave secure notes that
45 ;; only the intended recipient can read in a shared-org-mode-files
46 ;; scenario.
47 ;; If the key is not set, org-crypt will default to symmetric encryption.
49 ;; 3. To later decrypt an entry, use `org-decrypt-entries' or
50 ;; `org-decrypt-entry'. It might be useful to bind this to a key,
51 ;; like C-c C-/. I hope that in the future, C-c C-r can be might
52 ;; overloaded to also decrypt an entry if it's encrypted, since
53 ;; that fits nicely with the meaning of "reveal".
55 ;; 4. To automatically encrypt all necessary entries when saving a
56 ;; file, call `org-crypt-use-before-save-magic' after loading
57 ;; org-crypt.el.
59 ;;; Thanks:
61 ;; - Carsten Dominik
62 ;; - Vitaly Ostanin
64 (require 'org)
66 ;;; Code:
68 (declare-function epg-decrypt-string "epg" (context cipher))
69 (declare-function epg-list-keys "epg" (context &optional name mode))
70 (declare-function epg-make-context "epg"
71 (&optional protocol armor textmode include-certs
72 cipher-algorithm digest-algorithm
73 compress-algorithm))
74 (declare-function epg-encrypt-string "epg"
75 (context plain recipients &optional sign always-trust))
77 (defgroup org-crypt nil
78 "Org Crypt"
79 :tag "Org Crypt"
80 :group 'org)
82 (defcustom org-crypt-tag-matcher "crypt"
83 "The tag matcher used to find headings whose contents should be encrypted.
85 See the \"Match syntax\" section of the org manual for more details."
86 :type 'string
87 :group 'org-crypt)
89 (defcustom org-crypt-key ""
90 "The default key to use when encrypting the contents of a heading.
92 This setting can also be overridden in the CRYPTKEY property."
93 :type 'string
94 :group 'org-crypt)
96 (defcustom org-crypt-disable-auto-save 'ask
97 "What org-decrypt should do if `auto-save-mode' is enabled.
99 t : Disable auto-save-mode for the current buffer
100 prior to decrypting an entry.
102 nil : Leave auto-save-mode enabled.
103 This may cause data to be written to disk unencrypted!
105 'ask : Ask user whether or not to disable auto-save-mode
106 for the current buffer.
108 'encrypt : Leave auto-save-mode enabled for the current buffer,
109 but automatically re-encrypt all decrypted entries
110 *before* auto-saving.
111 NOTE: This only works for entries which have a tag
112 that matches `org-crypt-tag-matcher'."
113 :group 'org-crypt
114 :type '(choice (const :tag "Always" t)
115 (const :tag "Never" nil)
116 (const :tag "Ask" ask)
117 (const :tag "Encrypt" encrypt)))
119 (defun org-crypt-check-auto-save ()
120 "Check whether auto-save-mode is enabled for the current buffer.
122 `auto-save-mode' may cause leakage when decrypting entries, so
123 check whether it's enabled, and decide what to do about it.
125 See `org-crypt-disable-auto-save'."
126 (when buffer-auto-save-file-name
127 (cond
128 ((or
129 (eq org-crypt-disable-auto-save t)
130 (and
131 (eq org-crypt-disable-auto-save 'ask)
132 (y-or-n-p "org-decrypt: auto-save-mode may cause leakage. Disable it for current buffer? ")))
133 (message (concat "org-decrypt: Disabling auto-save-mode for " (or (buffer-file-name) (current-buffer))))
134 ; The argument to auto-save-mode has to be "-1", since
135 ; giving a "nil" argument toggles instead of disabling.
136 (auto-save-mode -1))
137 ((eq org-crypt-disable-auto-save nil)
138 (message "org-decrypt: Decrypting entry with auto-save-mode enabled. This may cause leakage."))
139 ((eq org-crypt-disable-auto-save 'encrypt)
140 (message "org-decrypt: Enabling re-encryption on auto-save.")
141 (add-hook 'auto-save-hook
142 (lambda ()
143 (message "org-crypt: Re-encrypting all decrypted entries due to auto-save.")
144 (org-encrypt-entries))
145 nil t))
146 (t nil))))
148 (defun org-crypt-key-for-heading ()
149 "Return the encryption key for the current heading."
150 (save-excursion
151 (org-back-to-heading t)
152 (or (org-entry-get nil "CRYPTKEY" 'selective)
153 org-crypt-key
154 (and (boundp 'epa-file-encrypt-to) epa-file-encrypt-to)
155 (message "No crypt key set, using symmetric encryption."))))
157 (defun org-encrypt-string (str crypt-key)
158 "Return STR encrypted with CRYPT-KEY."
159 ;; Text and key have to be identical, otherwise we re-crypt.
160 (if (and (string= crypt-key (get-text-property 0 'org-crypt-key str))
161 (string= (sha1 str) (get-text-property 0 'org-crypt-checksum str)))
162 (get-text-property 0 'org-crypt-text str)
163 (let ((epg-context (epg-make-context nil t t)))
164 (epg-encrypt-string epg-context str (epg-list-keys epg-context crypt-key)))))
166 (defun org-encrypt-entry ()
167 "Encrypt the content of the current headline."
168 (interactive)
169 (require 'epg)
170 (save-excursion
171 (org-back-to-heading t)
172 (let ((start-heading (point)))
173 (forward-line)
174 (when (not (looking-at "-----BEGIN PGP MESSAGE-----"))
175 (let ((folded (outline-invisible-p))
176 (epg-context (epg-make-context nil t t))
177 (crypt-key (org-crypt-key-for-heading))
178 (beg (point))
179 end encrypted-text)
180 (goto-char start-heading)
181 (org-end-of-subtree t t)
182 (org-back-over-empty-lines)
183 (setq end (point)
184 encrypted-text
185 (org-encrypt-string (buffer-substring beg end) crypt-key))
186 (delete-region beg end)
187 (insert encrypted-text)
188 (when folded
189 (goto-char start-heading)
190 (hide-subtree))
191 nil)))))
193 (defun org-decrypt-entry ()
194 "Decrypt the content of the current headline."
195 (interactive)
196 (require 'epg)
197 (unless (org-before-first-heading-p)
198 (save-excursion
199 (org-back-to-heading t)
200 (let ((heading-point (point))
201 (heading-was-invisible-p
202 (save-excursion
203 (outline-end-of-heading)
204 (outline-invisible-p))))
205 (forward-line)
206 (when (looking-at "-----BEGIN PGP MESSAGE-----")
207 (org-crypt-check-auto-save)
208 (let* ((end (save-excursion
209 (search-forward "-----END PGP MESSAGE-----")
210 (forward-line)
211 (point)))
212 (epg-context (epg-make-context nil t t))
213 (encrypted-text (buffer-substring-no-properties (point) end))
214 (decrypted-text
215 (decode-coding-string
216 (epg-decrypt-string
217 epg-context
218 encrypted-text)
219 'utf-8)))
220 ;; Delete region starting just before point, because the
221 ;; outline property starts at the \n of the heading.
222 (delete-region (1- (point)) end)
223 ;; Store a checksum of the decrypted and the encrypted
224 ;; text value. This allow to reuse the same encrypted text
225 ;; if the text does not change, and therefore avoid a
226 ;; re-encryption process.
227 (insert "\n" (propertize decrypted-text
228 'org-crypt-checksum (sha1 decrypted-text)
229 'org-crypt-key (org-crypt-key-for-heading)
230 'org-crypt-text encrypted-text))
231 (when heading-was-invisible-p
232 (goto-char heading-point)
233 (org-flag-subtree t))
234 nil))))))
236 (defun org-encrypt-entries ()
237 "Encrypt all top-level entries in the current buffer."
238 (interactive)
239 (let (todo-only)
240 (org-scan-tags
241 'org-encrypt-entry
242 (cdr (org-make-tags-matcher org-crypt-tag-matcher))
243 todo-only)))
245 (defun org-decrypt-entries ()
246 "Decrypt all entries in the current buffer."
247 (interactive)
248 (let (todo-only)
249 (org-scan-tags
250 'org-decrypt-entry
251 (cdr (org-make-tags-matcher org-crypt-tag-matcher))
252 todo-only)))
254 (defun org-crypt-use-before-save-magic ()
255 "Add a hook to automatically encrypt entries before a file is saved to disk."
256 (add-hook
257 'org-mode-hook
258 (lambda () (add-hook 'before-save-hook 'org-encrypt-entries nil t))))
260 (add-hook 'org-reveal-start-hook 'org-decrypt-entry)
262 (provide 'org-crypt)
264 ;;; org-crypt.el ends here