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Diffstat (limited to 'lisp/net/rfc2104.el')
| -rw-r--r-- | lisp/net/rfc2104.el | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/lisp/net/rfc2104.el b/lisp/net/rfc2104.el new file mode 100644 index 00000000000..f80e2287879 --- /dev/null +++ b/lisp/net/rfc2104.el @@ -0,0 +1,124 @@ +;;; rfc2104.el --- RFC2104 Hashed Message Authentication Codes + +;; Copyright (C) 1998-2015 Free Software Foundation, Inc. + +;; Author: Simon Josefsson <jas@pdc.kth.se> +;; Keywords: mail + +;; 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 of the License, 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. If not, see <http://www.gnu.org/licenses/>. + +;;; Commentary: + +;; This is a high performance implementation of RFC2104. +;; +;; Example: +;; +;; (require 'md5) +;; (rfc2104-hash 'md5 64 16 "Jefe" "what do ya want for nothing?") +;; "750c783e6ab0b503eaa86e310a5db738" +;; +;; (require 'sha1) +;; (rfc2104-hash 'sha1 64 20 "Jefe" "what do ya want for nothing?") +;; "effcdf6ae5eb2fa2d27416d5f184df9c259a7c79" +;; +;; 64 is block length of hash function (64 for MD5 and SHA), 16 is +;; resulting hash length (16 for MD5, 20 for SHA). +;; +;; Tested with Emacs 20.2 and XEmacs 20.3. +;; +;; Test case reference: RFC 2202. + +;;; History: + +;; 1998-08-16 initial release posted to gnu.emacs.sources +;; 1998-08-17 use append instead of char-list-to-string +;; 1998-08-26 don't require hexl +;; 1998-09-25 renamed from hmac.el to rfc2104.el, also renamed functions +;; 1999-10-23 included in pgnus +;; 2000-08-15 `rfc2104-hexstring-to-bitstring' +;; 2000-05-12 added sha-1 example, added test case reference +;; 2003-11-13 change rfc2104-hexstring-to-bitstring to ...-byte-list +;; 2008-04-25 rewrite rfc2104-hash for speed + +;;; Code: + +(eval-when-compile (require 'cl)) + +;; Magic character for inner HMAC round. 0x36 == 54 == '6' +(defconst rfc2104-ipad ?\x36) + +;; Magic character for outer HMAC round. 0x5C == 92 == '\' +(defconst rfc2104-opad ?\x5C) + +(defconst rfc2104-nybbles + (let ((v (make-vector + ;; Find upper bound to save some space. + (1+ (max ?0 ?9 ?a ?f ?A ?F)) + ;; Use non-numeric default to catch bogus hex strings. + nil)) + (ls '((?0 . 0) (?a . 10) (?A . 10) + (?1 . 1) (?b . 11) (?B . 11) + (?2 . 2) (?c . 12) (?C . 12) + (?3 . 3) (?d . 13) (?D . 13) + (?4 . 4) (?e . 14) (?E . 14) + (?5 . 5) (?f . 15) (?F . 15) + (?6 . 6) + (?7 . 7) + (?8 . 8) + (?9 . 9)))) + (while ls + (aset v (caar ls) (cdar ls)) + (setq ls (cdr ls))) + v)) + +(eval-when-compile + (defmacro rfc2104-string-make-unibyte (string) + "Return the unibyte equivalent of STRING. +In XEmacs return just STRING." + (if (featurep 'xemacs) + string + `(string-make-unibyte ,string)))) + +(defun rfc2104-hash (hash block-length hash-length key text) + (let* (;; if key is longer than B, reset it to HASH(key) + (key (if (> (length key) block-length) + (funcall hash key) key)) + (len (length key)) + (ipad (make-string block-length rfc2104-ipad)) + (opad (make-string (+ block-length hash-length) rfc2104-opad)) + c partial) + ;; Prefix *pad with key, appropriately XORed. + (do ((i 0 (1+ i))) + ((= len i)) + (setq c (aref key i)) + (aset ipad i (logxor rfc2104-ipad c)) + (aset opad i (logxor rfc2104-opad c))) + ;; Perform inner hash. + (setq partial (rfc2104-string-make-unibyte + (funcall hash (concat ipad text)))) + ;; Pack latter part of opad. + (do ((r 0 (+ 2 r)) + (w block-length (1+ w))) + ((= (* 2 hash-length) r)) + (aset opad w + (+ (* 16 (aref rfc2104-nybbles (aref partial r))) + ( aref rfc2104-nybbles (aref partial (1+ r)))))) + ;; Perform outer hash. + (rfc2104-string-make-unibyte (funcall hash opad)))) + +(provide 'rfc2104) + +;;; rfc2104.el ends here |