Commit 62e8183e authored by Dave Love's avatar Dave Love
Browse files

2000-11-09 Simon Josefsson <simon@josefsson.org>

	* rfc2104.el: Add SHA-1 example.
	(rfc2104-hexstring-to-bitstring): New function.
	(rfc2104-hash): Use it.
parent 59896c4c
;;; rfc2104.el --- RFC2104 Hashed Message Authentication Codes
;; Copyright (C) 1998,1999 Free Software Foundation, Inc.
;; Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
;; Author: Simon Josefsson <jas@pdc.kth.se>
;; Keywords: mail
......@@ -31,10 +31,16 @@
;;; (rfc2104-hash 'md5 64 16 "Jefe" "what do ya want for nothing?")
;;; "750c783e6ab0b503eaa86e310a5db738"
;;;
;;; (require 'sha-1)
;;; (rfc2104-hash 'sha1-encode 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.
;;; Release history:
;;;
......@@ -43,6 +49,8 @@
;;; 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
(eval-when-compile (require 'cl))
......@@ -76,6 +84,13 @@
(rfc2104-hex-to-int (reverse (append str nil))))
0))
(defun rfc2104-hexstring-to-bitstring (str)
(let (out)
(while (< 0 (length str))
(push (rfc2104-hex-to-int (substring str -2)) out)
(setq str (substring str 0 -2)))
(concat out)))
(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)
......@@ -90,14 +105,10 @@
;; XOR key with ipad/opad into k_ipad/k_opad
(setq k_ipad (mapcar (lambda (c) (logxor c rfc2104-ipad)) k_ipad))
(setq k_opad (mapcar (lambda (c) (logxor c rfc2104-opad)) k_opad))
;; perform inner hash
(let ((first-round (funcall hash (concat k_ipad text)))
de-hexed)
(while (< 0 (length first-round))
(push (rfc2104-hex-to-int (substring first-round -2)) de-hexed)
(setq first-round (substring first-round 0 -2)))
;; perform outer hash
(funcall hash (concat k_opad de-hexed)))))
;; perform outer hash
(funcall hash (concat k_opad (rfc2104-hexstring-to-bitstring
;; perform inner hash
(funcall hash (concat k_ipad text)))))))
(provide 'rfc2104)
......
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