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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-11-29 07:58:28 +00:00
emacs/lisp/md4.el
Paul Eggert bc511a64f6 Prefer HTTPS to FTP and HTTP in documentation
Most of this change is to boilerplate commentary such as license URLs.
This change was prompted by ftp://ftp.gnu.org's going-away party,
planned for November.  Change these FTP URLs to https://ftp.gnu.org
instead.  Make similar changes for URLs to other organizations moving
away from FTP.  Also, change HTTP to HTTPS for URLs to gnu.org and
fsf.org when this works, as this will further help defend against
man-in-the-middle attacks (for this part I omitted the MS-DOS and
MS-Windows sources and the test tarballs to keep the workload down).
HTTPS is not fully working to lists.gnu.org so I left those URLs alone
for now.
2017-09-13 15:54:37 -07:00

229 lines
8.3 KiB
EmacsLisp

;;; md4.el --- MD4 Message Digest Algorithm. -*- lexical-binding: t -*-
;; Copyright (C) 2001, 2004, 2007-2017 Free Software Foundation, Inc.
;; Author: Taro Kawagishi <tarok@transpulse.org>
;; Keywords: MD4
;; Version: 1.00
;; Created: February 2001
;; 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 <https://www.gnu.org/licenses/>.
;;; Code:
;;;
;;; MD4 hash calculation
(defvar md4-buffer (make-vector 4 '(0 . 0))
"Work buffer of four 32-bit integers.")
(defun md4 (in n)
"Return the MD4 hash for a string IN of length N bytes.
The returned hash is 16 bytes long. N is required to handle
strings containing the character 0."
(let (m
(b (cons 0 (* n 8)))
(i 0)
(buf (make-string 128 0)) c4)
;; initial values
(aset md4-buffer 0 '(26437 . 8961)) ;0x67452301
(aset md4-buffer 1 '(61389 . 43913)) ;0xefcdab89
(aset md4-buffer 2 '(39098 . 56574)) ;0x98badcfe
(aset md4-buffer 3 '(4146 . 21622)) ;0x10325476
;; process the string in 64 bits chunks
(while (> n 64)
(setq m (md4-copy64 (substring in 0 64)))
(md4-64 m)
(setq in (substring in 64))
(setq n (- n 64)))
;; process the rest of the string (length is now n <= 64)
(setq i 0)
(while (< i n)
(aset buf i (aref in i))
(setq i (1+ i)))
(aset buf n 128) ;0x80
(if (<= n 55)
(progn
(setq c4 (md4-pack-int32 b))
(aset buf 56 (aref c4 0))
(aset buf 57 (aref c4 1))
(aset buf 58 (aref c4 2))
(aset buf 59 (aref c4 3))
(setq m (md4-copy64 buf))
(md4-64 m))
;; else
(setq c4 (md4-pack-int32 b))
(aset buf 120 (aref c4 0))
(aset buf 121 (aref c4 1))
(aset buf 122 (aref c4 2))
(aset buf 123 (aref c4 3))
(setq m (md4-copy64 buf))
(md4-64 m)
(setq m (md4-copy64 (substring buf 64)))
(md4-64 m)))
(concat (md4-pack-int32 (aref md4-buffer 0))
(md4-pack-int32 (aref md4-buffer 1))
(md4-pack-int32 (aref md4-buffer 2))
(md4-pack-int32 (aref md4-buffer 3))))
(defsubst md4-F (x y z) (logior (logand x y) (logand (lognot x) z)))
(defsubst md4-G (x y z) (logior (logand x y) (logand x z) (logand y z)))
(defsubst md4-H (x y z) (logxor x y z))
(defmacro md4-make-step (name func)
`(defun ,name (a b c d xk s ac)
(let*
((h1 (+ (car a) (,func (car b) (car c) (car d)) (car xk) (car ac)))
(l1 (+ (cdr a) (,func (cdr b) (cdr c) (cdr d)) (cdr xk) (cdr ac)))
(h2 (logand 65535 (+ h1 (lsh l1 -16))))
(l2 (logand 65535 l1))
;; cyclic shift of 32 bits integer
(h3 (logand 65535 (if (> s 15)
(+ (lsh h2 (- s 32)) (lsh l2 (- s 16)))
(+ (lsh h2 s) (lsh l2 (- s 16))))))
(l3 (logand 65535 (if (> s 15)
(+ (lsh l2 (- s 32)) (lsh h2 (- s 16)))
(+ (lsh l2 s) (lsh h2 (- s 16)))))))
(cons h3 l3))))
(md4-make-step md4-round1 md4-F)
(md4-make-step md4-round2 md4-G)
(md4-make-step md4-round3 md4-H)
(defsubst md4-add (x y)
"Return 32-bit sum of 32-bit integers X and Y."
(let ((h (+ (car x) (car y)))
(l (+ (cdr x) (cdr y))))
(cons (logand 65535 (+ h (lsh l -16))) (logand 65535 l))))
(defsubst md4-and (x y)
(cons (logand (car x) (car y)) (logand (cdr x) (cdr y))))
(defun md4-64 (m)
"Calculate MD4 hash of M.
M is a 64-bytes chunk, represented as 16 pairs of 32-bit integers.
The resulting MD4 value is placed in `md4-buffer'."
(let ((a (aref md4-buffer 0))
(b (aref md4-buffer 1))
(c (aref md4-buffer 2))
(d (aref md4-buffer 3)))
(setq a (md4-round1 a b c d (aref m 0) 3 '(0 . 0))
d (md4-round1 d a b c (aref m 1) 7 '(0 . 0))
c (md4-round1 c d a b (aref m 2) 11 '(0 . 0))
b (md4-round1 b c d a (aref m 3) 19 '(0 . 0))
a (md4-round1 a b c d (aref m 4) 3 '(0 . 0))
d (md4-round1 d a b c (aref m 5) 7 '(0 . 0))
c (md4-round1 c d a b (aref m 6) 11 '(0 . 0))
b (md4-round1 b c d a (aref m 7) 19 '(0 . 0))
a (md4-round1 a b c d (aref m 8) 3 '(0 . 0))
d (md4-round1 d a b c (aref m 9) 7 '(0 . 0))
c (md4-round1 c d a b (aref m 10) 11 '(0 . 0))
b (md4-round1 b c d a (aref m 11) 19 '(0 . 0))
a (md4-round1 a b c d (aref m 12) 3 '(0 . 0))
d (md4-round1 d a b c (aref m 13) 7 '(0 . 0))
c (md4-round1 c d a b (aref m 14) 11 '(0 . 0))
b (md4-round1 b c d a (aref m 15) 19 '(0 . 0))
a (md4-round2 a b c d (aref m 0) 3 '(23170 . 31129)) ;0x5A827999
d (md4-round2 d a b c (aref m 4) 5 '(23170 . 31129))
c (md4-round2 c d a b (aref m 8) 9 '(23170 . 31129))
b (md4-round2 b c d a (aref m 12) 13 '(23170 . 31129))
a (md4-round2 a b c d (aref m 1) 3 '(23170 . 31129))
d (md4-round2 d a b c (aref m 5) 5 '(23170 . 31129))
c (md4-round2 c d a b (aref m 9) 9 '(23170 . 31129))
b (md4-round2 b c d a (aref m 13) 13 '(23170 . 31129))
a (md4-round2 a b c d (aref m 2) 3 '(23170 . 31129))
d (md4-round2 d a b c (aref m 6) 5 '(23170 . 31129))
c (md4-round2 c d a b (aref m 10) 9 '(23170 . 31129))
b (md4-round2 b c d a (aref m 14) 13 '(23170 . 31129))
a (md4-round2 a b c d (aref m 3) 3 '(23170 . 31129))
d (md4-round2 d a b c (aref m 7) 5 '(23170 . 31129))
c (md4-round2 c d a b (aref m 11) 9 '(23170 . 31129))
b (md4-round2 b c d a (aref m 15) 13 '(23170 . 31129))
a (md4-round3 a b c d (aref m 0) 3 '(28377 . 60321)) ;0x6ED9EBA1
d (md4-round3 d a b c (aref m 8) 9 '(28377 . 60321))
c (md4-round3 c d a b (aref m 4) 11 '(28377 . 60321))
b (md4-round3 b c d a (aref m 12) 15 '(28377 . 60321))
a (md4-round3 a b c d (aref m 2) 3 '(28377 . 60321))
d (md4-round3 d a b c (aref m 10) 9 '(28377 . 60321))
c (md4-round3 c d a b (aref m 6) 11 '(28377 . 60321))
b (md4-round3 b c d a (aref m 14) 15 '(28377 . 60321))
a (md4-round3 a b c d (aref m 1) 3 '(28377 . 60321))
d (md4-round3 d a b c (aref m 9) 9 '(28377 . 60321))
c (md4-round3 c d a b (aref m 5) 11 '(28377 . 60321))
b (md4-round3 b c d a (aref m 13) 15 '(28377 . 60321))
a (md4-round3 a b c d (aref m 3) 3 '(28377 . 60321))
d (md4-round3 d a b c (aref m 11) 9 '(28377 . 60321))
c (md4-round3 c d a b (aref m 7) 11 '(28377 . 60321))
b (md4-round3 b c d a (aref m 15) 15 '(28377 . 60321)))
(aset md4-buffer 0 (md4-add a (aref md4-buffer 0)))
(aset md4-buffer 1 (md4-add b (aref md4-buffer 1)))
(aset md4-buffer 2 (md4-add c (aref md4-buffer 2)))
(aset md4-buffer 3 (md4-add d (aref md4-buffer 3)))
))
(defun md4-copy64 (seq)
"Unpack a 64 bytes string into 16 pairs of 32 bits integers."
(let ((int32s (make-vector 16 0)) (i 0) j)
(while (< i 16)
(setq j (* i 4))
(aset int32s i (cons (+ (aref seq (+ j 2)) (lsh (aref seq (+ j 3)) 8))
(+ (aref seq j) (lsh (aref seq (1+ j)) 8))))
(setq i (1+ i)))
int32s))
;;;
;;; sub functions
(defun md4-pack-int16 (int16)
"Pack 16 bits integer in 2 bytes string as little endian."
(let ((str (make-string 2 0)))
(aset str 0 (logand int16 255))
(aset str 1 (lsh int16 -8))
str))
(defun md4-pack-int32 (int32)
"Pack 32 bits integer in a 4 bytes string as little endian.
A 32 bits integer is represented as a pair of two 16 bits
integers (cons high low)."
(let ((str (make-string 4 0))
(h (car int32)) (l (cdr int32)))
(aset str 0 (logand l 255))
(aset str 1 (lsh l -8))
(aset str 2 (logand h 255))
(aset str 3 (lsh h -8))
str))
(defun md4-unpack-int16 (str)
(if (eq 2 (length str))
(+ (lsh (aref str 1) 8) (aref str 0))
(error "%s is not 2 bytes long" str)))
(defun md4-unpack-int32 (str)
(if (eq 4 (length str))
(cons (+ (lsh (aref str 3) 8) (aref str 2))
(+ (lsh (aref str 1) 8) (aref str 0)))
(error "%s is not 4 bytes long" str)))
(provide 'md4)
;;; md4.el ends here