Commit b737c3d9 authored by Thien-Thi Nguyen's avatar Thien-Thi Nguyen
Browse files

Rewrite rfc2104-hash for speed.

* rfc2104.el (rfc2104-zero): Delete defconst.
(rfc2104-hex-alist): Likewise.
(rfc2104-hex-to-int): Delete func.
(rfc2104-hexstring-to-bitstring): Likewise.
(rfc2104-nybbles): New defconst.
(rfc2104-hash): Rewrite for speed.
parent 76afdf7e
2008-07-21 Thien-Thi Nguyen <ttn@gnuvola.org>
* rfc2104.el (rfc2104-zero): Delete defconst.
(rfc2104-hex-alist): Likewise.
(rfc2104-hex-to-int): Delete func.
(rfc2104-hexstring-to-bitstring): Likewise.
(rfc2104-nybbles): New defconst.
(rfc2104-hash): Rewrite for speed.
2008-07-16 Glenn Morris <rgm@gnu.org>
* gnus-util.el (ns-focus-frame): Declare for compiler.
......
......@@ -23,7 +23,7 @@
;;; Commentary:
;; This is a quick'n'dirty, low performance, implementation of RFC2104.
;; This is a high performance implementation of RFC2104.
;;
;; Example:
;;
......@@ -31,8 +31,8 @@
;; (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?")
;; (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
......@@ -52,6 +52,7 @@
;; 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:
......@@ -63,55 +64,52 @@
;; Magic character for outer HMAC round. 0x5C == 92 == '\'
(defconst rfc2104-opad ?\x5C)
;; Not so magic character for padding the key. 0x00
(defconst rfc2104-zero ?\x00)
;; Alist for converting hex to decimal.
(defconst rfc2104-hex-alist
'((?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)))
(defun rfc2104-hex-to-int (str)
(if str
(if (listp str)
(+ (* 16 (rfc2104-hex-to-int (cdr str)))
(cdr (assoc (car str) rfc2104-hex-alist)))
(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)))
(apply (if (fboundp 'unibyte-string) 'unibyte-string 'string) out)))
(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))
(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))
(k_ipad (append key nil))
(k_opad (append key nil)))
;; zero pad k_ipad/k_opad
(while (< (length k_ipad) block-length)
(setq k_ipad (append k_ipad (list rfc2104-zero))))
(while (< (length k_opad) block-length)
(setq k_opad (append k_opad (list rfc2104-zero))))
;; 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 outer hash
(funcall hash (concat k_opad (rfc2104-hexstring-to-bitstring
;; perform inner hash
(funcall hash (concat k_ipad text)))))))
(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 (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.
(string-make-unibyte (funcall hash opad))))
(provide 'rfc2104)
......
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