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;;; encrypt.el --- file encryption routines
;; Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
;; Author: Teodor Zlatanov <tzz@lifelogs.com>
;; Created: 2003/01/24
;; Keywords: files
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 3, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Commentary:
;;; This module addresses data encryption. Page breaks are used for
;;; grouping declarations and documentation relating to each
;;; particular aspect.
;;; Use in Gnus like this:
;;; (setq
;;; nnimap-authinfo-file "~/.authinfo.enc"
;;; nntp-authinfo-file "~/.authinfo.enc"
;;; smtpmail-auth-credentials "~/.authinfo.enc"
;;; ;; using the AES256 cipher, feel free to use your own favorite
;;; encrypt-file-alist (quote (("~/.authinfo.enc" (gpg "AES256"))))
;;; password-cache-expiry 600)
;;; Then write ~/.authinfo.enc:
;;; 1) open the old authinfo
;;; C-x C-f ~/.authinfo
;;; 2) write the new authinfo.enc
;;; M-x encrypt-file-contents ~/.authinfo.enc
;;; 3) verify the new authinfo is correct (this will show the contents in the minibuffer)
;;; M-: (encrypt-get-file-contents "~/.authinfo.enc")
;;; Code:
;; autoload password
(eval-and-compile
(autoload 'password-read "password"))
(defgroup encrypt '((password-cache custom-variable)
(password-cache-expiry custom-variable))
"File encryption configuration."
:group 'applications)
(defcustom encrypt-file-alist nil
"List of file names or regexes matched with encryptions.
Format example:
'((\"beta\"
(gpg \"AES\"))
(\"/home/tzz/alpha\"
(encrypt-xor \"Semi-Secret\")))"
:type '(repeat
(list :tag "Encryption entry"
(radio :tag "What to encrypt"
(file :tag "Filename")
(regexp :tag "Regular expression match"))
(radio :tag "How to encrypt it"
(list
:tag "GPG Encryption"
(const :tag "GPG Program" gpg)
(radio :tag "Choose a cipher"
(const :tag "3DES Encryption" "3DES")
(const :tag "CAST5 Encryption" "CAST5")
(const :tag "Blowfish Encryption" "BLOWFISH")
(const :tag "AES Encryption" "AES")
(const :tag "AES192 Encryption" "AES192")
(const :tag "AES256 Encryption" "AES256")
(const :tag "Twofish Encryption" "TWOFISH")
(string :tag "Cipher Name")))
(list
:tag "Built-in simple XOR"
(const :tag "XOR Encryption" encrypt-xor)
(string :tag "XOR Cipher Value (seed value)")))))
:group 'encrypt)
;; TODO: now, load gencrypt.el and if successful, modify the
;; custom-type of encrypt-file-alist to add the gencrypt.el options
;; (plist-get (symbol-plist 'encrypt-file-alist) 'custom-type)
;; then use plist-put
(defcustom encrypt-gpg-path (executable-find "gpg")
"Path to the GPG program."
:type '(radio
(file :tag "Location of the GPG executable")
(const :tag "GPG is not installed" nil))
:group 'encrypt)
(defvar encrypt-temp-prefix "encrypt"
"Prefix for temporary filenames")
;;;###autoload
(defun encrypt-find-model (filename)
"Given a filename, find a encrypt-file-alist entry"
(dolist (entry encrypt-file-alist)
(let ((match (nth 0 entry))
(model (nth 1 entry)))
(when (or (eq match filename)
(string-match match filename))
(return model)))))
;;;###autoload
(defun encrypt-insert-file-contents (file &optional model)
"Decrypt FILE into the current buffer."
(interactive "fFile to insert: ")
(let* ((model (or model (encrypt-find-model file)))
(method (nth 0 model))
(cipher (nth 1 model))
(password-key (format "encrypt-password-%s-%s %s"
(symbol-name method) cipher file))
(passphrase
(password-read-and-add
(format "%s password for cipher %s (file %s)? "
file (symbol-name method) cipher)
password-key))
(buffer-file-coding-system 'binary)
(coding-system-for-read 'binary)
outdata)
;; note we only insert-file-contents if the method is known to be valid
(cond
((eq method 'gpg)
(insert-file-contents file)
(setq outdata (encrypt-gpg-decode-buffer passphrase cipher)))
((eq method 'encrypt-xor)
(insert-file-contents file)
(setq outdata (encrypt-xor-decode-buffer passphrase cipher))))
(if outdata
(progn
(message "%s was decrypted with %s (cipher %s)"
file (symbol-name method) cipher)
(delete-region (point-min) (point-max))
(goto-char (point-min))
(insert outdata))
;; the decryption failed, alas
(password-cache-remove password-key)
(gnus-error 5 "%s was NOT decrypted with %s (cipher %s)"
file (symbol-name method) cipher))))
(defun encrypt-get-file-contents (file &optional model)
"Decrypt FILE and return the contents."
(interactive "fFile to decrypt: ")
(with-temp-buffer
(encrypt-insert-file-contents file model)
(buffer-string)))
(defun encrypt-put-file-contents (file data &optional model)
"Encrypt the DATA to FILE, then continue normally."
(with-temp-buffer
(insert data)
(encrypt-write-file-contents file model)))
(defun encrypt-write-file-contents (file &optional model)
"Encrypt the current buffer to FILE, then continue normally."
(interactive "sFile to write: ")
(setq model (or model (encrypt-find-model file)))
(if model
(let* ((method (nth 0 model))
(cipher (nth 1 model))
(password-key (format "encrypt-password-%s-%s %s"
(symbol-name method) cipher file))
(passphrase
(password-read
(format "%s password for cipher %s? "
(symbol-name method) cipher)
password-key))
outdata)
(cond
((eq method 'gpg)
(setq outdata (encrypt-gpg-encode-buffer passphrase cipher)))
((eq method 'encrypt-xor)
(setq outdata (encrypt-xor-encode-buffer passphrase cipher))))
(if outdata
(progn
(message "%s was encrypted with %s (cipher %s)"
file (symbol-name method) cipher)
(delete-region (point-min) (point-max))
(goto-char (point-min))
(insert outdata)
;; do not confirm overwrites
(write-file file nil))
;; the decryption failed, alas
(password-cache-remove password-key)
(gnus-error 5 "%s was NOT encrypted with %s (cipher %s)"
file (symbol-name method) cipher)))
(gnus-error 1 "%s has no associated encryption model! See encrypt-file-alist." file)))
(defun encrypt-xor-encode-buffer (passphrase cipher)
(encrypt-xor-process-buffer passphrase cipher t))
(defun encrypt-xor-decode-buffer (passphrase cipher)
(encrypt-xor-process-buffer passphrase cipher nil))
(defun encrypt-xor-process-buffer (passphrase
cipher
&optional encode)
"Given PASSPHRASE, xor-encode or decode the contents of the current buffer."
(let* ((bs (buffer-substring-no-properties (point-min) (point-max)))
;; passphrase-sum is a simple additive checksum of the
;; passphrase and the cipher
(passphrase-sum
(when (stringp passphrase)
(apply '+ (append cipher passphrase nil))))
new-list)
(with-temp-buffer
(if encode
(progn
(dolist (x (append bs nil))
(setq new-list (cons (logxor x passphrase-sum) new-list)))
(dolist (x new-list)
(insert (format "%d " x))))
(progn
(setq new-list (reverse (split-string bs)))
(dolist (x new-list)
(setq x (string-to-number x))
(insert (format "%c" (logxor x passphrase-sum))))))
(buffer-substring-no-properties (point-min) (point-max)))))
(defun encrypt-gpg-encode-buffer (passphrase cipher)
(encrypt-gpg-process-buffer passphrase cipher t))
(defun encrypt-gpg-decode-buffer (passphrase cipher)
(encrypt-gpg-process-buffer passphrase cipher nil))
(defun encrypt-gpg-process-buffer (passphrase
cipher
&optional encode)
"With PASSPHRASE, use GPG to encode or decode the current buffer."
(let* ((program encrypt-gpg-path)
(input (buffer-substring-no-properties (point-min) (point-max)))
(temp-maker (if (fboundp 'make-temp-file)
'make-temp-file
'make-temp-name))
(temp-file (funcall temp-maker encrypt-temp-prefix))
(default-enable-multibyte-characters nil)
(args `("--cipher-algo" ,cipher
"--status-fd" "2"
"--logger-fd" "2"
"--passphrase-fd" "0"
"--no-tty"))
exit-status exit-data)
(when encode
(setq args
(append args
'("--symmetric"
"--armor"))))
(if program
(with-temp-buffer
(when passphrase
(insert passphrase "\n"))
(insert input)
(setq exit-status
(apply #'call-process-region (point-min) (point-max) program
t `(t ,temp-file) nil args))
(if (equal exit-status 0)
(setq exit-data
(buffer-substring-no-properties (point-min) (point-max)))
(with-temp-buffer
(when (file-exists-p temp-file)
(insert-file-contents temp-file))
(gnus-error 5 (format "%s exited abnormally: '%s' [%s]"
program exit-status (buffer-string)))))
(delete-file temp-file))
(gnus-error 5 "GPG is not installed."))
exit-data))
(provide 'encrypt)
;;; encrypt.el ends here
;; arch-tag: d907e4f1-71b5-42b1-a180-fc7b84ff0648
|
