# Re: [PHP] How can I decrypt a password I previously coded with m d5()?

```
Hey !!!
you're lucky, I just foud it :

------------------------------->
/*
* A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
* Digest Algorithm, as defined in RFC 1321.
* Copyright (C) Paul Johnston 1999 - 2000.
* Updated by Greg Holt 2000 - 2001.
* See http://pajhome.org.uk/site/legal.html for details.
*/

/*
* Convert a 32-bit number to a hex string with ls-byte first
*/
var hex_chr = "0123456789abcdef";
function rhex(num)
{
str = "";
for(j = 0; j <= 3; j++)
str += hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) +
hex_chr.charAt((num >> (j * 8)) & 0x0F);
return str;
}

/*
* Convert a string to a sequence of 16-word blocks, stored as an array.
* Append padding bits and the length, as described in the MD5 standard.
*/
function str2blks_MD5(str)
{
nblk = ((str.length + 8) >> 6) + 1;
blks = new Array(nblk * 16);
for(i = 0; i < nblk * 16; i++) blks[i] = 0;
for(i = 0; i < str.length; i++)
blks[i >> 2] |= str.charCodeAt(i) << ((i % 4) * 8);
blks[i >> 2] |= 0x80 << ((i % 4) * 8);
blks[nblk * 16 - 2] = str.length * 8;
return blks;
}

/*
* Add integers, wrapping at 2^32. This uses 16-bit operations internally
* to work around bugs in some JS interpreters.
*/
{
var lsw = (x & 0xFFFF) + (y & 0xFFFF);
var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
return (msw << 16) | (lsw & 0xFFFF);
}

/*
* Bitwise rotate a 32-bit number to the left
*/
function rol(num, cnt)
{
return (num << cnt) | (num >>> (32 - cnt));
}

/*
* These functions implement the basic operation for each round of the
* algorithm.
*/
function cmn(q, a, b, x, s, t)
{
}
function ff(a, b, c, d, x, s, t)
{
return cmn((b & c) | ((~b) & d), a, b, x, s, t);
}
function gg(a, b, c, d, x, s, t)
{
return cmn((b & d) | (c & (~d)), a, b, x, s, t);
}
function hh(a, b, c, d, x, s, t)
{
return cmn(b ^ c ^ d, a, b, x, s, t);
}
function ii(a, b, c, d, x, s, t)
{
return cmn(c ^ (b | (~d)), a, b, x, s, t);
}

/*
* Take a string and return the hex representation of its MD5.
*/
function calcMD5(str)
{
x = str2blks_MD5(str);
a =  1732584193;
b = -271733879;
c = -1732584194;
d =  271733878;

for(i = 0; i < x.length; i += 16)
{
olda = a;
oldb = b;
oldc = c;
oldd = d;

a = ff(a, b, c, d, x[i+ 0], 7 , -680876936);
d = ff(d, a, b, c, x[i+ 1], 12, -389564586);
c = ff(c, d, a, b, x[i+ 2], 17,  606105819);
b = ff(b, c, d, a, x[i+ 3], 22, -1044525330);
a = ff(a, b, c, d, x[i+ 4], 7 , -176418897);
d = ff(d, a, b, c, x[i+ 5], 12,  1200080426);
c = ff(c, d, a, b, x[i+ 6], 17, -1473231341);
b = ff(b, c, d, a, x[i+ 7], 22, -45705983);
a = ff(a, b, c, d, x[i+ 8], 7 ,  1770035416);
d = ff(d, a, b, c, x[i+ 9], 12, -1958414417);
c = ff(c, d, a, b, x[i+10], 17, -42063);
b = ff(b, c, d, a, x[i+11], 22, -1990404162);
a = ff(a, b, c, d, x[i+12], 7 ,  1804603682);
d = ff(d, a, b, c, x[i+13], 12, -40341101);
c = ff(c, d, a, b, x[i+14], 17, -1502002290);
b = ff(b, c, d, a, x[i+15], 22,  1236535329);

a = gg(a, b, c, d, x[i+ 1], 5 , -165796510);
d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632);
c = gg(c, d, a, b, x[i+11], 14,  643717713);
b = gg(b, c, d, a, x[i+ 0], 20, -373897302);
a = gg(a, b, c, d, x[i+ 5], 5 , -701558691);
d = gg(d, a, b, c, x[i+10], 9 ,  38016083);
c = gg(c, d, a, b, x[i+15], 14, -660478335);
b = gg(b, c, d, a, x[i+ 4], 20, -405537848);
a = gg(a, b, c, d, x[i+ 9], 5 ,  568446438);
d = gg(d, a, b, c, x[i+14], 9 , -1019803690);
c = gg(c, d, a, b, x[i+ 3], 14, -187363961);
b = gg(b, c, d, a, x[i+ 8], 20,  1163531501);
a = gg(a, b, c, d, x[i+13], 5 , -1444681467);
d = gg(d, a, b, c, x[i+ 2], 9 , -51403784);
c = gg(c, d, a, b, x[i+ 7], 14,  1735328473);
b = gg(b, c, d, a, x[i+12], 20, -1926607734);

a = hh(a, b, c, d, x[i+ 5], 4 , -378558);
d = hh(d, a, b, c, x[i+ 8], 11, -2022574463);
c = hh(c, d, a, b, x[i+11], 16,  1839030562);
b = hh(b, c, d, a, x[i+14], 23, -35309556);
a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060);
d = hh(d, a, b, c, x[i+ 4], 11,  1272893353);
c = hh(c, d, a, b, x[i+ 7], 16, -155497632);
b = hh(b, c, d, a, x[i+10], 23, -1094730640);
a = hh(a, b, c, d, x[i+13], 4 ,  681279174);
d = hh(d, a, b, c, x[i+ 0], 11, -358537222);
c = hh(c, d, a, b, x[i+ 3], 16, -722521979);
b = hh(b, c, d, a, x[i+ 6], 23,  76029189);
a = hh(a, b, c, d, x[i+ 9], 4 , -640364487);
d = hh(d, a, b, c, x[i+12], 11, -421815835);
c = hh(c, d, a, b, x[i+15], 16,  530742520);
b = hh(b, c, d, a, x[i+ 2], 23, -995338651);

a = ii(a, b, c, d, x[i+ 0], 6 , -198630844);
d = ii(d, a, b, c, x[i+ 7], 10,  1126891415);
c = ii(c, d, a, b, x[i+14], 15, -1416354905);
b = ii(b, c, d, a, x[i+ 5], 21, -57434055);
a = ii(a, b, c, d, x[i+12], 6 ,  1700485571);
d = ii(d, a, b, c, x[i+ 3], 10, -1894986606);
c = ii(c, d, a, b, x[i+10], 15, -1051523);
b = ii(b, c, d, a, x[i+ 1], 21, -2054922799);
a = ii(a, b, c, d, x[i+ 8], 6 ,  1873313359);
d = ii(d, a, b, c, x[i+15], 10, -30611744);
c = ii(c, d, a, b, x[i+ 6], 15, -1560198380);
b = ii(b, c, d, a, x[i+13], 21,  1309151649);
a = ii(a, b, c, d, x[i+ 4], 6 , -145523070);
d = ii(d, a, b, c, x[i+11], 10, -1120210379);
c = ii(c, d, a, b, x[i+ 2], 15,  718787259);
b = ii(b, c, d, a, x[i+ 9], 21, -343485551);

}
return rhex(a) + rhex(b) + rhex(c) + rhex(d);
}

----------------------------------<

Le Mercredi 30 Janvier 2002 13:15, Ford, Mike               [LSS] a écrit :
> > -----Original Message-----
> > From: Nicolas Costes [mailto:[EMAIL PROTECTED]]
> > Sent: 30 January 2002 10:19
> >
> > And for more security, I use a JavaScript MD5 function to encrypt the
> > provided password in the user's browser so it goes already
> > encrypted on the
> > net ... Then PHP's just got to compare it with the one in the
> > database !!!
>
> Any chance of getting a look at this function, to save reinventing the
> wheel?
>
> Cheers!
>
> Mike
>
> ---------------------------------------------------------------------
> Mike Ford,  Electronic Information Services Adviser,
> Learning Support Services, Learning & Information Services,
> JG125, James Graham Building, Leeds Metropolitan University,
> Beckett Park, LEEDS,  LS6 3QS,  United Kingdom
> Email: [EMAIL PROTECTED]
> Tel: +44 113 283 2600 extn 4730      Fax:  +44 113 283 3211

--
( °> Nicolas Costes
//\\  IUT de La Roche / Yon
/ \/ ) [EMAIL PROTECTED]
`-<<  http://luxregina.free.fr

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