Convert Java MD5 `java.security.MessageDigest.getInstance(“MD5”)` code to Python2.7 using hashlib or other methods

Question

Java code:

public static String md5(byte[] source) throws NoSuchAlgorithmException {
    char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    java.security.MessageDigest md = java.security.MessageDigest.getInstance("MD5");
    md.update(source);
    byte tmp[] = md.digest();
    char str[] = new char[32];
    int k = 0;
    for (int i = 0; i < 16; i++) {
      str[k++] = hexDigits[tmp[i] >>> 4 & 0xf];
      str[k++] = hexDigits[tmp[i] & 0xf];
    }

    return new String(str);
  }

And that code, input:

77,48,48,47,48,48,47,48,48,47,114,66,65,72,104,108,120,121,80,107,113,65,89,90,78,106,65,65,67,102,97,85,116,51,77,89,52,55,53,46,106,112,101,103,49,49

return:

2fa040f96503fdabf5fd171da1473069

Then in python2.7, my code:

def md5(string):
    m = hashlib.md5()
    m.update(string)
    return m.hexdigest()

same input and return:

e480188fdf66deeec3d5a2c42094dd73

So how to edit my python code to have same return?

Answer 1

Taking a closer look at your input string 774848474848474848471146665721... it looks like a concatenated-together sequence of byte values representing ASCII characters:

77 48 48 47 48 48 47 48 48 47 114 66 65 72 ...

Converting these to characters we obtain the string M00/00/00/rBAHhlxyPkqAYZNjAACfaUt3MY475.jpeg11 .

Computing the MD5 hash of M00/00/00/rBAHhlxyPkqAYZNjAACfaUt3MY475.jpeg11 , I get 2fa040f96503fdabf5fd171da1473069 . This is the hash returned by your Java code.

On the other hand, computing the MD5 hash of the string 774848474848474848471146665721... returns e480188fdf66deeec3d5a2c42094dd73 . This is the hash returned by your Python code.

I have been able to calculate both of these hashes using your Java code and your Python code, and get the same results in both. To convert a string to a byte array in Java I called .getBytes("UTF-8") on the string. (I used Python 3 rather than Python 2, and so had to insert a call to .encode("utf-8") , but that's an aside.)

Therefore, your Java and Python code samples for computing MD5 hashes are returning different results because you are passing them different input data.