• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 1398
  • Last Modified:

Java MD5 doesn't match php?

Java:
------------------------------------------------------
StringBuffer sb = new StringBuffer();

        try {
            String data = "apple";
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            messageDigest.update(data.getBytes());
            byte[] digestBytes = messageDigest.digest();

            /* convert to hexstring */
            String hex = null;

            for (int i = 0; i < digestBytes.length; i++) {
                hex = Integer.toHexString(0xFF & digestBytes[i]);

                if (hex.length() < 2) {
                    sb.append("0");
                    sb.append(hex);
                }
                sb.append(hex);
            }
        }
        catch (Exception ex) {
            System.out.println(ex.getMessage());
        }

        System.out.println(sb.toString());

PHP:
------------------------------------------------------
echo md5("apple");
or http://tw.php.net/md5

--
I got a
1f3870be274f6c49b3e31a0cc6728957f (from Java)
1f3870be274f6c49b3e31a0c6728957f  (from PHP)

always differ one bit.

Thanks in advance:)
0
YuRen
Asked:
YuRen
  • 3
  • 2
  • 2
1 Solution
 
jimmackCommented:
               if (hex.length() < 2) {
                    sb.append("0");
                    sb.append(hex);
                }
                sb.append(hex);

should be:

                if (hex.length() < 2) {
                    sb.append("0");
                }
                sb.append(hex);

You were appending "hex" twice if you found a value less than 0x10 ;-)
0
 
YuRenAuthor Commented:
You save my life, jimmack
:)

A few days later, I would implement the security scheme in my web site.
http://www.uwan.com.tw/   Enjoy it!
0
 
jimmackCommented:
;-)
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
kelvinlawCommented:
may i ask :

hex = Integer.toHexString(0xFF & digestBytes[i]);

why 0xFF is needed?
0xFF should be 11111111

0xFF & digestBytes[i] same as  digestBytes[i] ??

thanks
0
 
YuRenAuthor Commented:
0xff shoud be 00000000 00000000 00000000 11111111

--
        byte[] digestBytes = { (byte) 0x7f, (byte) 0x8f, (byte) 0xff };

        for (int i = 0; i < digestBytes.length; i++) {
            System.out.print(Integer.toHexString(digestBytes[i]) + "\t");
            System.out.print(Integer.toHexString(0xff & digestBytes[i]) + "\t");
        }
--
result:
7f      7f      ffffff8f      8f      ffffffff      ff      
0
 
kelvinlawCommented:
1 byte is 8 bits, right?
but
System.out.print(Integer.toBinaryString(digestBytes[i])

if give me a 32 bits answer if digestBytes[i] >= 0x80....


WHY????
0
 
YuRenAuthor Commented:
0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

  • 3
  • 2
  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now