An MD5 implementation for my final project (look inside)

Question

Hey, I'll just cut to the chase: I'm making an MD5 implementation, from the pseudo-code on the wikipedia page, which is located here. This is what I have so far:
import java.util.Random;
public class MD {
static int i = 0;
static int f,g;
public static String MD5(String df) {
//Note: All variables are unsigned 32 bits and wrap modulo 2^32 when calculating
//r specifies the per-round shift amounts
int[] k = new int[64];
int r[] = {7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22,
5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20,
4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23,
6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21};
{color:#000000}
{color}
{color:#000000}//Use binary integer part of the sines of integers (Radians) as constants:
for (int i = 0; i <= 63; i++)
k[i] =
+*}{color}*+
Random gen = new Random();+
*//Initialize variables:*
int h0 = 0x67452301;+
int h1 = 0xEFCDAB89;+
int h2 = 0x98BADCFE;+
int h3 = 0x10325476;+
+*{color:#ff6600}//Pre-processing:*+
*df {color}*+{color:#ff6600}*= 0x1;*
*//TODO: append "0" bits until message length in bits = 448 (% 512);*
*//**append bit / bit, not byte / length of unpadded message as 64-bit little-endian integer to message*
+//Process the message in successive 512-bit chunks:+
for each 512-bit chunk of message*
+break chunk into sixteen 32-bit little-endian words w, 0 <= i <= 15+*
+/+
+//Initialize hash value for this chunk:+
int w[] = new int[16];
for (int i = 0; i < w.length; i+)
w[i] = 0;
//what do I do here?
}{color}
int a = h0;
int b = h1;
int c = h2;
int d = h3;
//Main loop:
//from 0 to 63
for (; i < 64; i++)
if (0 <= i && i <= 15)
f = (b & c) | ((~ b) & d);
g = i;
else if (16 <= i && i <= 31)
f = (d & b) | ((~ d) & c);
g = (5*i +1) % 16;+
+}+
else if (32 <= i && i <= 47)
+{+
f = b ^ c ^ d;
g = (3*i 5) % 16;
else if (48 <= i && i <= 63)
f = c ^ (b | (~ d));
g = (7*i) % 16;
int temp = d;
//can be declared earlier?
d = c;
c = b;
{color:#ff6600}b += leftrotate((a ++ f + +k[i] ++ w[g]) , r[i]);{color}
a = temp;
//Add this chunk's hash to result so far:
h0 += a;+
h1 = b;
h2 += c;+
h3 = d;
int digest = h0 h1 h2 + h3;
String valrtn = Integer.toHexString(digest);
return valrtn;
//leftrotate function definition
{color:#ff6600}private static int leftrotate (int x, int c)
return ((x << c) | (x >> (32-c)));
//for some reason, this usually gives an error...
}{color}private static String ToHex (String df)
//not used right now...
public static void main (String[]args)
System.out.println(MD5((("1234567891113111"))));
//add to hex later
// String df = "1278186781234567812345678";
//s.t(df.substring(0,15));
//-1 from both
(The above code is copyright me, Chris Blake, and cannot be used without my permission, except for the comments, they're not mine.)
I'm having a problem with the colored parts, the first part is the part that's supposed to break the plaintext into chunks. (ignore the bold please) I just haven't quite figured out how to do it yet, and it always returns 88888884. The other orange parts have explanations with them.
Thanks in advance to all that help. :D
Also, is this in the right forum? Thanks in advance.
Edited by: Zeroknight on May 26, 2009 5:04 PM
Edited by: Zeroknight on May 26, 2009 5:15 PM

Answer 1

Hi,
You're going to find that there's only a very small group of people that want to install a program with a known exploit, and the developers aren't going to be keen on allowing ongoing access to faulty code.
Best bet would be to look for the source code. On the [http://www.oracle.com/technetwork/java/javase/downloads/index.html Oracle website] there's the source for JDK 6; have a look around there. You may have to drop back a version to get access.
Ian.