| commit | author | age | ||
| 76bbd0 | 1 | ;;; org-crypt.el --- Public Key Encryption for Org Entries -*- lexical-binding: t; -*- |
| C | 2 | ;; Copyright (C) 2007-2018 Free Software Foundation, Inc. |
| 3 | ||
| 4 | ;; Emacs Lisp Archive Entry | |
| 5 | ;; Filename: org-crypt.el | |
| 6 | ;; Keywords: org-mode | |
| 7 | ;; Author: John Wiegley <johnw@gnu.org> | |
| 8 | ;; Maintainer: Peter Jones <pjones@pmade.com> | |
| 9 | ;; Description: Adds public key encryption to Org buffers | |
| 10 | ;; URL: http://www.newartisans.com/software/emacs.html | |
| 11 | ;; Compatibility: Emacs22 | |
| 12 | ||
| 13 | ;; This file is part of GNU Emacs. | |
| 14 | ;; | |
| 15 | ;; GNU Emacs is free software: you can redistribute it and/or modify | |
| 16 | ;; it under the terms of the GNU General Public License as published by | |
| 17 | ;; the Free Software Foundation, either version 3 of the License, or | |
| 18 | ;; (at your option) any later version. | |
| 19 | ||
| 20 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
| 21 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 22 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 23 | ;; GNU General Public License for more details. | |
| 24 | ||
| 25 | ;; You should have received a copy of the GNU General Public License | |
| 26 | ;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. | |
| 27 | ||
| 28 | ;;; Commentary: | |
| 29 | ||
| 30 | ;; Right now this is just a set of functions to play with. It depends | |
| 31 | ;; on the epg library. Here's how you would use it: | |
| 32 | ;; | |
| 33 | ;; 1. To mark an entry for encryption, tag the heading with "crypt". | |
| 34 | ;; You can change the tag to any complex tag matching string by | |
| 35 | ;; setting the `org-crypt-tag-matcher' variable. | |
| 36 | ;; | |
| 37 | ;; 2. Set the encryption key to use in the `org-crypt-key' variable, | |
| 38 | ;; or use `M-x org-set-property' to set the property CRYPTKEY to | |
| 39 | ;; any address in your public keyring. The text of the entry (but | |
| 40 | ;; not its properties or headline) will be encrypted for this user. | |
| 41 | ;; For them to read it, the corresponding secret key must be | |
| 42 | ;; located in the secret key ring of the account where you try to | |
| 43 | ;; decrypt it. This makes it possible to leave secure notes that | |
| 44 | ;; only the intended recipient can read in a shared-org-mode-files | |
| 45 | ;; scenario. | |
| 46 | ;; If the key is not set, org-crypt will default to symmetric encryption. | |
| 47 | ;; | |
| 48 | ;; 3. To later decrypt an entry, use `org-decrypt-entries' or | |
| 49 | ;; `org-decrypt-entry'. It might be useful to bind this to a key, | |
| 50 | ;; like C-c C-/. I hope that in the future, C-c C-r can be might | |
| 51 | ;; overloaded to also decrypt an entry if it's encrypted, since | |
| 52 | ;; that fits nicely with the meaning of "reveal". | |
| 53 | ;; | |
| 54 | ;; 4. To automatically encrypt all necessary entries when saving a | |
| 55 | ;; file, call `org-crypt-use-before-save-magic' after loading | |
| 56 | ;; org-crypt.el. | |
| 57 | ||
| 58 | ;;; Thanks: | |
| 59 | ||
| 60 | ;; - Carsten Dominik | |
| 61 | ;; - Vitaly Ostanin | |
| 62 | ||
| 63 | (require 'org) | |
| 64 | ||
| 65 | ;;; Code: | |
| 66 | ||
| 67 | (declare-function epg-decrypt-string "epg" (context cipher)) | |
| 68 | (declare-function epg-list-keys "epg" (context &optional name mode)) | |
| 69 | (declare-function epg-make-context "epg" | |
| 70 | (&optional protocol armor textmode include-certs | |
| 71 | cipher-algorithm digest-algorithm | |
| 72 | compress-algorithm)) | |
| 73 | (declare-function epg-encrypt-string "epg" | |
| 74 | (context plain recipients &optional sign always-trust)) | |
| 75 | (defvar epg-context) | |
| 76 | ||
| 77 | ||
| 78 | (defgroup org-crypt nil | |
| 79 | "Org Crypt." | |
| 80 | :tag "Org Crypt" | |
| 81 | :group 'org) | |
| 82 | ||
| 83 | (defcustom org-crypt-tag-matcher "crypt" | |
| 84 | "The tag matcher used to find headings whose contents should be encrypted. | |
| 85 | ||
| 86 | See the \"Match syntax\" section of the org manual for more details." | |
| 87 | :type 'string | |
| 88 | :group 'org-crypt) | |
| 89 | ||
| 90 | (defcustom org-crypt-key "" | |
| 91 | "The default key to use when encrypting the contents of a heading. | |
| 92 | ||
| 93 | This setting can also be overridden in the CRYPTKEY property." | |
| 94 | :type 'string | |
| 95 | :group 'org-crypt) | |
| 96 | ||
| 97 | (defcustom org-crypt-disable-auto-save 'ask | |
| 98 | "What org-decrypt should do if `auto-save-mode' is enabled. | |
| 99 | ||
| 100 | t : Disable auto-save-mode for the current buffer | |
| 101 | prior to decrypting an entry. | |
| 102 | ||
| 103 | nil : Leave auto-save-mode enabled. | |
| 104 | This may cause data to be written to disk unencrypted! | |
| 105 | ||
| 106 | `ask' : Ask user whether or not to disable auto-save-mode | |
| 107 | for the current buffer. | |
| 108 | ||
| 109 | `encrypt': Leave auto-save-mode enabled for the current buffer, | |
| 110 | but automatically re-encrypt all decrypted entries | |
| 111 | *before* auto-saving. | |
| 112 | NOTE: This only works for entries which have a tag | |
| 113 | that matches `org-crypt-tag-matcher'." | |
| 114 | :group 'org-crypt | |
| 115 | :version "24.1" | |
| 116 | :type '(choice (const :tag "Always" t) | |
| 117 | (const :tag "Never" nil) | |
| 118 | (const :tag "Ask" ask) | |
| 119 | (const :tag "Encrypt" encrypt))) | |
| 120 | ||
| 121 | (defun org-crypt-check-auto-save () | |
| 122 | "Check whether auto-save-mode is enabled for the current buffer. | |
| 123 | ||
| 124 | `auto-save-mode' may cause leakage when decrypting entries, so | |
| 125 | check whether it's enabled, and decide what to do about it. | |
| 126 | ||
| 127 | See `org-crypt-disable-auto-save'." | |
| 128 | (when buffer-auto-save-file-name | |
| 129 | (cond | |
| 130 | ((or | |
| 131 | (eq org-crypt-disable-auto-save t) | |
| 132 | (and | |
| 133 | (eq org-crypt-disable-auto-save 'ask) | |
| 134 | (y-or-n-p "org-decrypt: auto-save-mode may cause leakage. Disable it for current buffer? "))) | |
| 135 | (message "org-decrypt: Disabling auto-save-mode for %s" | |
| 136 | (or (buffer-file-name) (current-buffer))) | |
| 137 | ;; The argument to auto-save-mode has to be "-1", since | |
| 138 | ;; giving a "nil" argument toggles instead of disabling. | |
| 139 | (auto-save-mode -1)) | |
| 140 | ((eq org-crypt-disable-auto-save nil) | |
| 141 | (message "org-decrypt: Decrypting entry with auto-save-mode enabled. This may cause leakage.")) | |
| 142 | ((eq org-crypt-disable-auto-save 'encrypt) | |
| 143 | (message "org-decrypt: Enabling re-encryption on auto-save.") | |
| 144 | (add-hook 'auto-save-hook | |
| 145 | (lambda () | |
| 146 | (message "org-crypt: Re-encrypting all decrypted entries due to auto-save.") | |
| 147 | (org-encrypt-entries)) | |
| 148 | nil t)) | |
| 149 | (t nil)))) | |
| 150 | ||
| 151 | (defun org-crypt-key-for-heading () | |
| 152 | "Return the encryption key for the current heading." | |
| 153 | (save-excursion | |
| 154 | (org-back-to-heading t) | |
| 155 | (or (org-entry-get nil "CRYPTKEY" 'selective) | |
| 156 | org-crypt-key | |
| 157 | (and (boundp 'epa-file-encrypt-to) epa-file-encrypt-to) | |
| 158 | (message "No crypt key set, using symmetric encryption.")))) | |
| 159 | ||
| 160 | (defun org-encrypt-string (str crypt-key) | |
| 161 | "Return STR encrypted with CRYPT-KEY." | |
| 162 | ;; Text and key have to be identical, otherwise we re-crypt. | |
| 163 | (if (and (string= crypt-key (get-text-property 0 'org-crypt-key str)) | |
| 164 | (string= (sha1 str) (get-text-property 0 'org-crypt-checksum str))) | |
| 165 | (get-text-property 0 'org-crypt-text str) | |
| 166 | (setq-local epg-context (epg-make-context nil t t)) | |
| 167 | (epg-encrypt-string epg-context str (epg-list-keys epg-context crypt-key)))) | |
| 168 | ||
| 169 | (defun org-encrypt-entry () | |
| 170 | "Encrypt the content of the current headline." | |
| 171 | (interactive) | |
| 172 | (require 'epg) | |
| 173 | (org-with-wide-buffer | |
| 174 | (org-back-to-heading t) | |
| 175 | (setq-local epg-context (epg-make-context nil t t)) | |
| 176 | (let ((start-heading (point))) | |
| 177 | (org-end-of-meta-data) | |
| 178 | (unless (looking-at-p "-----BEGIN PGP MESSAGE-----") | |
| 179 | (let ((folded (org-invisible-p)) | |
| 180 | (crypt-key (org-crypt-key-for-heading)) | |
| 181 | (beg (point))) | |
| 182 | (goto-char start-heading) | |
| 183 | (org-end-of-subtree t t) | |
| 184 | (org-back-over-empty-lines) | |
| 185 | (let ((contents (delete-and-extract-region beg (point)))) | |
| 186 | (condition-case err | |
| 187 | (insert (org-encrypt-string contents crypt-key)) | |
| 188 | ;; If encryption failed, make sure to insert back entry | |
| 189 | ;; contents in the buffer. | |
| 190 | (error (insert contents) (error (nth 1 err))))) | |
| 191 | (when folded | |
| 192 | (goto-char start-heading) | |
| 193 | (outline-hide-subtree)) | |
| 194 | nil))))) | |
| 195 | ||
| 196 | (defun org-decrypt-entry () | |
| 197 | "Decrypt the content of the current headline." | |
| 198 | (interactive) | |
| 199 | (require 'epg) | |
| 200 | (unless (org-before-first-heading-p) | |
| 201 | (org-with-wide-buffer | |
| 202 | (org-back-to-heading t) | |
| 203 | (let ((heading-point (point)) | |
| 204 | (heading-was-invisible-p | |
| 205 | (save-excursion | |
| 206 | (outline-end-of-heading) | |
| 207 | (org-invisible-p)))) | |
| 208 | (org-end-of-meta-data) | |
| 209 | (when (looking-at "-----BEGIN PGP MESSAGE-----") | |
| 210 | (org-crypt-check-auto-save) | |
| 211 | (setq-local epg-context (epg-make-context nil t t)) | |
| 212 | (let* ((end (save-excursion | |
| 213 | (search-forward "-----END PGP MESSAGE-----") | |
| 214 | (forward-line) | |
| 215 | (point))) | |
| 216 | (encrypted-text (buffer-substring-no-properties (point) end)) | |
| 217 | (decrypted-text | |
| 218 | (decode-coding-string | |
| 219 | (epg-decrypt-string | |
| 220 | epg-context | |
| 221 | encrypted-text) | |
| 222 | 'utf-8))) | |
| 223 | ;; Delete region starting just before point, because the | |
| 224 | ;; outline property starts at the \n of the heading. | |
| 225 | (delete-region (1- (point)) end) | |
| 226 | ;; Store a checksum of the decrypted and the encrypted | |
| 227 | ;; text value. This allows reusing the same encrypted text | |
| 228 | ;; if the text does not change, and therefore avoid a | |
| 229 | ;; re-encryption process. | |
| 230 | (insert "\n" (propertize decrypted-text | |
| 231 | 'org-crypt-checksum (sha1 decrypted-text) | |
| 232 | 'org-crypt-key (org-crypt-key-for-heading) | |
| 233 | 'org-crypt-text encrypted-text)) | |
| 234 | (when heading-was-invisible-p | |
| 235 | (goto-char heading-point) | |
| 236 | (org-flag-subtree t)) | |
| 237 | nil)))))) | |
| 238 | ||
| 239 | (defun org-encrypt-entries () | |
| 240 | "Encrypt all top-level entries in the current buffer." | |
| 241 | (interactive) | |
| 242 | (let ((org--matcher-tags-todo-only nil)) | |
| 243 | (org-scan-tags | |
| 244 | 'org-encrypt-entry | |
| 245 | (cdr (org-make-tags-matcher org-crypt-tag-matcher)) | |
| 246 | org--matcher-tags-todo-only))) | |
| 247 | ||
| 248 | (defun org-decrypt-entries () | |
| 249 | "Decrypt all entries in the current buffer." | |
| 250 | (interactive) | |
| 251 | (let ((org--matcher-tags-todo-only nil)) | |
| 252 | (org-scan-tags | |
| 253 | 'org-decrypt-entry | |
| 254 | (cdr (org-make-tags-matcher org-crypt-tag-matcher)) | |
| 255 | org--matcher-tags-todo-only))) | |
| 256 | ||
| 257 | (defun org-at-encrypted-entry-p () | |
| 258 | "Is the current entry encrypted?" | |
| 259 | (unless (org-before-first-heading-p) | |
| 260 | (save-excursion | |
| 261 | (org-back-to-heading t) | |
| 262 | (search-forward "-----BEGIN PGP MESSAGE-----" | |
| 263 | (save-excursion (outline-next-heading)) t)))) | |
| 264 | ||
| 265 | (defun org-crypt-use-before-save-magic () | |
| 266 | "Add a hook to automatically encrypt entries before a file is saved to disk." | |
| 267 | (add-hook | |
| 268 | 'org-mode-hook | |
| 269 | (lambda () (add-hook 'before-save-hook 'org-encrypt-entries nil t)))) | |
| 270 | ||
| 271 | (add-hook 'org-reveal-start-hook 'org-decrypt-entry) | |
| 272 | ||
| 273 | (provide 'org-crypt) | |
| 274 | ||
| 275 | ;;; org-crypt.el ends here | |
