11. marts 2003 - 14:43
#5
hUsername og hPassword er MD5 hash af dit brugernavn og password ("koder" og "password"). Et hash er irreversibelt, hvilket vil sige at det ikke er muligt at afkode "koder" og "password" fra de to hash værdier. Til gengæld kan man lave tilsvarende hash fra de indtastede værdier og sammenligne dem. Dette er NÆSTEN lige så sikkert som serverside validering. Den benyttede javascript fil (md5.js) er her:
/* md5.js - MD5 Message-Digest
* Copyright (C) 1999,2002 Masanao Izumo <mo@goice.co.jp>
* Version: 2.0.0
* LastModified: May 13 2002
*
* This program is free software. You can redistribute it and/or modify
* it without any warranty. This library calculates the MD5 based on RFC1321.
* See RFC1321 for more information and algorism.
*/
/* Interface:
* md5_128bits = MD5_hash(data);
* md5_hexstr = MD5_hexhash(data);
*/
/* ChangeLog
* 2002/05/13: Version 2.0.0 released
* NOTICE: API is changed.
* 2002/04/15: Bug fix about MD5 length.
*/
// md5_T[i] = parseInt(Math.abs(Math.sin(i)) * 4294967296.0);
var MD5_T = new Array(0x00000000, 0xd76aa478, 0xe8c7b756, 0x242070db,
0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613,
0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1,
0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e,
0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51,
0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681,
0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87,
0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9,
0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122,
0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60,
0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085,
0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8,
0xc4ac5665, 0xf4292244, 0x432aff97, 0xab9423a7,
0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d,
0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314,
0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb,
0xeb86d391);
var MD5_round1 = new Array(new Array( 0, 7, 1), new Array( 1,12, 2),
new Array( 2,17, 3), new Array( 3,22, 4),
new Array( 4, 7, 5), new Array( 5,12, 6),
new Array( 6,17, 7), new Array( 7,22, 8),
new Array( 8, 7, 9), new Array( 9,12,10),
new Array(10,17,11), new Array(11,22,12),
new Array(12, 7,13), new Array(13,12,14),
new Array(14,17,15), new Array(15,22,16));
var MD5_round2 = new Array(new Array( 1, 5,17), new Array( 6, 9,18),
new Array(11,14,19), new Array( 0,20,20),
new Array( 5, 5,21), new Array(10, 9,22),
new Array(15,14,23), new Array( 4,20,24),
new Array( 9, 5,25), new Array(14, 9,26),
new Array( 3,14,27), new Array( 8,20,28),
new Array(13, 5,29), new Array( 2, 9,30),
new Array( 7,14,31), new Array(12,20,32));
var MD5_round3 = new Array(new Array( 5, 4,33), new Array( 8,11,34),
new Array(11,16,35), new Array(14,23,36),
new Array( 1, 4,37), new Array( 4,11,38),
new Array( 7,16,39), new Array(10,23,40),
new Array(13, 4,41), new Array( 0,11,42),
new Array( 3,16,43), new Array( 6,23,44),
new Array( 9, 4,45), new Array(12,11,46),
new Array(15,16,47), new Array( 2,23,48));
var MD5_round4 = new Array(new Array( 0, 6,49), new Array( 7,10,50),
new Array(14,15,51), new Array( 5,21,52),
new Array(12, 6,53), new Array( 3,10,54),
new Array(10,15,55), new Array( 1,21,56),
new Array( 8, 6,57), new Array(15,10,58),
new Array( 6,15,59), new Array(13,21,60),
new Array( 4, 6,61), new Array(11,10,62),
new Array( 2,15,63), new Array( 9,21,64));
function MD5_F(x, y, z) { return (x & y) | (~x & z); }
function MD5_G(x, y, z) { return (x & z) | (y & ~z); }
function MD5_H(x, y, z) { return x ^ y ^ z; }
function MD5_I(x, y, z) { return y ^ (x | ~z); }
var MD5_round = new Array(new Array(MD5_F, MD5_round1),
new Array(MD5_G, MD5_round2),
new Array(MD5_H, MD5_round3),
new Array(MD5_I, MD5_round4));
function MD5_pack(n32) {
return String.fromCharCode(n32 & 0xff) +
String.fromCharCode((n32 >>> 8) & 0xff) +
String.fromCharCode((n32 >>> 16) & 0xff) +
String.fromCharCode((n32 >>> 24) & 0xff);
}
function MD5_unpack(s4) {
return s4.charCodeAt(0) |
(s4.charCodeAt(1) << 8) |
(s4.charCodeAt(2) << 16) |
(s4.charCodeAt(3) << 24);
}
function MD5_number(n) {
while (n < 0)
n += 4294967296;
while (n > 4294967295)
n -= 4294967296;
return n;
}
function MD5_apply_round(x, s, f, abcd, r) {
var a, b, c, d;
var kk, ss, ii;
var t, u;
a = abcd[0];
b = abcd[1];
c = abcd[2];
d = abcd[3];
kk = r[0];
ss = r[1];
ii = r[2];
u = f(s[b], s[c], s[d]);
t = s[a] + u + x[kk] + MD5_T[ii];
t = MD5_number(t);
t = ((t<<ss) | (t>>>(32-ss)));
t += s[b];
s[a] = MD5_number(t);
}
function MD5_hash(data) {
var abcd, x, state, s;
var len, index, padLen, f, r;
var i, j, k;
var tmp;
state = new Array(0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476);
len = data.length;
index = len & 0x3f;
padLen = (index < 56) ? (56 - index) : (120 - index);
if(padLen > 0) {
data += "\x80";
for(i = 0; i < padLen - 1; i++)
data += "\x00";
}
data += MD5_pack(len * 8);
data += MD5_pack(0);
len += padLen + 8;
abcd = new Array(0, 1, 2, 3);
x = new Array(16);
s = new Array(4);
for(k = 0; k < len; k += 64) {
for(i = 0, j = k; i < 16; i++, j += 4) {
x[i] = data.charCodeAt(j) |
(data.charCodeAt(j + 1) << 8) |
(data.charCodeAt(j + 2) << 16) |
(data.charCodeAt(j + 3) << 24);
}
for(i = 0; i < 4; i++)
s[i] = state[i];
for(i = 0; i < 4; i++) {
f = MD5_round[i][0];
r = MD5_round[i][1];
for(j = 0; j < 16; j++) {
MD5_apply_round(x, s, f, abcd, r[j]);
tmp = abcd[0];
abcd[0] = abcd[3];
abcd[3] = abcd[2];
abcd[2] = abcd[1];
abcd[1] = tmp;
}
}
for(i = 0; i < 4; i++) {
state[i] += s[i];
state[i] = MD5_number(state[i]);
}
}
return MD5_pack(state[0]) +
MD5_pack(state[1]) +
MD5_pack(state[2]) +
MD5_pack(state[3]);
}
function MD5_hexhash(data) {
var i, out, c;
var bit128;
bit128 = MD5_hash(data);
out = "";
for(i = 0; i < 16; i++) {
c = bit128.charCodeAt(i);
out += "0123456789abcdef".charAt((c>>4) & 0xf);
out += "0123456789abcdef".charAt(c & 0xf);
}
return out;
}
