Auch mit Javascript kann man einen MD5 Hash erzeugen. Leider bietet Javascript nicht wie PHP gleich eine fertige Funktion dafür. Deswegen müssen wir sie uns selber schreiben.
Da das Internet voller Überraschungen ist gibt es schon diverse Leute, die das für uns erledigt haben. Wir müssen jetzt nur noch die Funktion in unsere Webseite kopieren und schon können wir sie benutzen.
function md5(str) {
var xl;
var rotateLeft = function(lValue, iShiftBits) {
return (lValue << iShiftBits) | (lValue >>> (32 - iShiftBits));
};
var addUnsigned = function(lX, lY) {
var lX4, lY4, lX8, lY8, lResult;
lX8 = (lX & 0x80000000);
lY8 = (lY & 0x80000000);
lX4 = (lX & 0x40000000);
lY4 = (lY & 0x40000000);
lResult = (lX & 0x3FFFFFFF) + (lY & 0x3FFFFFFF);
if (lX4 & lY4) {
return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
}
if (lX4 | lY4) {
if (lResult & 0x40000000) {
return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
} else {
return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
}
} else {
return (lResult ^ lX8 ^ lY8);
}
};
var _F = function(x, y, z) {
return (x & y) | ((~x) & z);
};
var _G = function(x, y, z) {
return (x & z) | (y & (~z));
};
var _H = function(x, y, z) {
return (x ^ y ^ z);
};
var _I = function(x, y, z) {
return (y ^ (x | (~z)));
};
var _FF = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(_F(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var _GG = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(_G(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var _HH = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(_H(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var _II = function(a, b, c, d, x, s, ac) {
a = addUnsigned(a, addUnsigned(addUnsigned(_I(b, c, d), x), ac));
return addUnsigned(rotateLeft(a, s), b);
};
var convertToWordArray = function(str) {
var lWordCount;
var lMessageLength = str.length;
var lNumberOfWords_temp1 = lMessageLength + 8;
var lNumberOfWords_temp2 = (lNumberOfWords_temp1 - (lNumberOfWords_temp1 % 64)) / 64;
var lNumberOfWords = (lNumberOfWords_temp2 + 1) * 16;
var lWordArray = new Array(lNumberOfWords - 1);
var lBytePosition = 0;
var lByteCount = 0;
while (lByteCount < lMessageLength) {
lWordCount = (lByteCount - (lByteCount % 4)) / 4;
lBytePosition = (lByteCount % 4) * 8;
lWordArray[lWordCount] = (lWordArray[lWordCount] | (str.charCodeAt(lByteCount) << lBytePosition));
lByteCount++;
}
lWordCount = (lByteCount - (lByteCount % 4)) / 4;
lBytePosition = (lByteCount % 4) * 8;
lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80 << lBytePosition);
lWordArray[lNumberOfWords - 2] = lMessageLength << 3; lWordArray[lNumberOfWords - 1] = lMessageLength >>> 29;
return lWordArray;
};
var wordToHex = function(lValue) {
var wordToHexValue = '',
wordToHexValue_temp = '',
lByte, lCount;
for (lCount = 0; lCount <= 3; lCount++) { lByte = (lValue >>> (lCount * 8)) & 255;
wordToHexValue_temp = '0' + lByte.toString(16);
wordToHexValue = wordToHexValue + wordToHexValue_temp.substr(wordToHexValue_temp.length - 2, 2);
}
return wordToHexValue;
};
var utf8_encode = function(string) {
string = (string+'').replace(/\r\n/g, "\n").replace(/\r/g, "\n");
var utftext = "";
var start, end;
var stringl = 0;
start = end = 0;
stringl = string.length;
for (var n = 0; n < stringl; n++) {
var c1 = string.charCodeAt(n);
var enc = null;
if (c1 < 128) { end++; } else if((c1 > 127) && (c1 < 2048)) { enc = String.fromCharCode((c1 >> 6) | 192) + String.fromCharCode((c1 & 63) | 128);
} else {
enc = String.fromCharCode((c1 >> 12) | 224) + String.fromCharCode(((c1 >> 6) & 63) | 128) + String.fromCharCode((c1 & 63) | 128);
}
if (enc != null) {
if (end > start) {
utftext += string.substring(start, end);
}
utftext += enc;
start = end = n+1;
}
}
if (end > start) {
utftext += string.substring(start, string.length);
}
return utftext;
}
var x = [],
k, AA, BB, CC, DD, a, b, c, d, S11 = 7,
S12 = 12,
S13 = 17,
S14 = 22,
S21 = 5,
S22 = 9,
S23 = 14,
S24 = 20,
S31 = 4,
S32 = 11,
S33 = 16,
S34 = 23,
S41 = 6,
S42 = 10,
S43 = 15,
S44 = 21;
str = utf8_encode(str);
x = convertToWordArray(str);
a = 0x67452301;
b = 0xEFCDAB89;
c = 0x98BADCFE;
d = 0x10325476;
xl = x.length;
for (k = 0; k < xl; k += 16) {
AA = a;
BB = b;
CC = c;
DD = d;
a = _FF(a, b, c, d, x[k + 0], S11, 0xD76AA478);
d = _FF(d, a, b, c, x[k + 1], S12, 0xE8C7B756);
c = _FF(c, d, a, b, x[k + 2], S13, 0x242070DB);
b = _FF(b, c, d, a, x[k + 3], S14, 0xC1BDCEEE);
a = _FF(a, b, c, d, x[k + 4], S11, 0xF57C0FAF);
d = _FF(d, a, b, c, x[k + 5], S12, 0x4787C62A);
c = _FF(c, d, a, b, x[k + 6], S13, 0xA8304613);
b = _FF(b, c, d, a, x[k + 7], S14, 0xFD469501);
a = _FF(a, b, c, d, x[k + 8], S11, 0x698098D8);
d = _FF(d, a, b, c, x[k + 9], S12, 0x8B44F7AF);
c = _FF(c, d, a, b, x[k + 10], S13, 0xFFFF5BB1);
b = _FF(b, c, d, a, x[k + 11], S14, 0x895CD7BE);
a = _FF(a, b, c, d, x[k + 12], S11, 0x6B901122);
d = _FF(d, a, b, c, x[k + 13], S12, 0xFD987193);
c = _FF(c, d, a, b, x[k + 14], S13, 0xA679438E);
b = _FF(b, c, d, a, x[k + 15], S14, 0x49B40821);
a = _GG(a, b, c, d, x[k + 1], S21, 0xF61E2562);
d = _GG(d, a, b, c, x[k + 6], S22, 0xC040B340);
c = _GG(c, d, a, b, x[k + 11], S23, 0x265E5A51);
b = _GG(b, c, d, a, x[k + 0], S24, 0xE9B6C7AA);
a = _GG(a, b, c, d, x[k + 5], S21, 0xD62F105D);
d = _GG(d, a, b, c, x[k + 10], S22, 0x2441453);
c = _GG(c, d, a, b, x[k + 15], S23, 0xD8A1E681);
b = _GG(b, c, d, a, x[k + 4], S24, 0xE7D3FBC8);
a = _GG(a, b, c, d, x[k + 9], S21, 0x21E1CDE6);
d = _GG(d, a, b, c, x[k + 14], S22, 0xC33707D6);
c = _GG(c, d, a, b, x[k + 3], S23, 0xF4D50D87);
b = _GG(b, c, d, a, x[k + 8], S24, 0x455A14ED);
a = _GG(a, b, c, d, x[k + 13], S21, 0xA9E3E905);
d = _GG(d, a, b, c, x[k + 2], S22, 0xFCEFA3F8);
c = _GG(c, d, a, b, x[k + 7], S23, 0x676F02D9);
b = _GG(b, c, d, a, x[k + 12], S24, 0x8D2A4C8A);
a = _HH(a, b, c, d, x[k + 5], S31, 0xFFFA3942);
d = _HH(d, a, b, c, x[k + 8], S32, 0x8771F681);
c = _HH(c, d, a, b, x[k + 11], S33, 0x6D9D6122);
b = _HH(b, c, d, a, x[k + 14], S34, 0xFDE5380C);
a = _HH(a, b, c, d, x[k + 1], S31, 0xA4BEEA44);
d = _HH(d, a, b, c, x[k + 4], S32, 0x4BDECFA9);
c = _HH(c, d, a, b, x[k + 7], S33, 0xF6BB4B60);
b = _HH(b, c, d, a, x[k + 10], S34, 0xBEBFBC70);
a = _HH(a, b, c, d, x[k + 13], S31, 0x289B7EC6);
d = _HH(d, a, b, c, x[k + 0], S32, 0xEAA127FA);
c = _HH(c, d, a, b, x[k + 3], S33, 0xD4EF3085);
b = _HH(b, c, d, a, x[k + 6], S34, 0x4881D05);
a = _HH(a, b, c, d, x[k + 9], S31, 0xD9D4D039);
d = _HH(d, a, b, c, x[k + 12], S32, 0xE6DB99E5);
c = _HH(c, d, a, b, x[k + 15], S33, 0x1FA27CF8);
b = _HH(b, c, d, a, x[k + 2], S34, 0xC4AC5665);
a = _II(a, b, c, d, x[k + 0], S41, 0xF4292244);
d = _II(d, a, b, c, x[k + 7], S42, 0x432AFF97);
c = _II(c, d, a, b, x[k + 14], S43, 0xAB9423A7);
b = _II(b, c, d, a, x[k + 5], S44, 0xFC93A039);
a = _II(a, b, c, d, x[k + 12], S41, 0x655B59C3);
d = _II(d, a, b, c, x[k + 3], S42, 0x8F0CCC92);
c = _II(c, d, a, b, x[k + 10], S43, 0xFFEFF47D);
b = _II(b, c, d, a, x[k + 1], S44, 0x85845DD1);
a = _II(a, b, c, d, x[k + 8], S41, 0x6FA87E4F);
d = _II(d, a, b, c, x[k + 15], S42, 0xFE2CE6E0);
c = _II(c, d, a, b, x[k + 6], S43, 0xA3014314);
b = _II(b, c, d, a, x[k + 13], S44, 0x4E0811A1);
a = _II(a, b, c, d, x[k + 4], S41, 0xF7537E82);
d = _II(d, a, b, c, x[k + 11], S42, 0xBD3AF235);
c = _II(c, d, a, b, x[k + 2], S43, 0x2AD7D2BB);
b = _II(b, c, d, a, x[k + 9], S44, 0xEB86D391);
a = addUnsigned(a, AA);
b = addUnsigned(b, BB);
c = addUnsigned(c, CC);
d = addUnsigned(d, DD);
}
var temp = wordToHex(a) + wordToHex(b) + wordToHex(c) + wordToHex(d);
return temp.toLowerCase();
}Was könnte man mit einem MD5 Hash alles anfangen?
Ein Beispiele wäre ein Gutschein Code. Diesen könnt ihr in eurer Script als fertig generierten MD5 Hash hinterlegen. Dann generiert ihr aus dem eingegeben Gutschein Code den MD5 Hash und vergleicht ihn mit eurem hinterlegtem. Stimmen sie überein ist es der richtige Code. Da man aus dem MD5 Hash nicht wieder zurück wandeln kann ist es auch sichergestellt das niemand in euren Code den Code raus bekommen kann.