Question

I need a PHP version of the following C# code:

string dateSince = "2010-02-01";
string siteID = "bash.org";
string sharedSecret = "12345"; // the same combination on my luggage!

using System.Security.Cryptography;

MD5CryptoServiceProvider x = new MD5CryptoServiceProvider();
byte[] dataBytes = System.Text.Encoding.ASCII.GetBytes(string.Format("{0}{1}{2}",   dateSince,  siteID, sharedSecret));
string result = BitConverter.ToString(x.ComputeHash(dataBytes));

… this code snippet appears to be incomplete. But here’s what I think is going on:

1. concatenating dateSince, siteID, and sharedSecret. Stealing underpants.

2. ???

3. converting that string into a ascii encoded byte array.

4. taking the MD5 hash of that array.

This mysterious BitConverter object appears to be converting that MD5 hashed array, into a string of hexadecimal numbers. According to the aforementioned doc, the value of result should look something like: “6D-E9-9A-B6-73-D8-10-79-BC-4F-EE-51-A4-84-15-D8”

Any help is greatly appreciated!!

---

Forgot to include this earlier. Here’s the PHP version of what I’ve written so far:

$date_since = "2010-02-01";
$site_id = "bash.org";
$shared_secret = "12345";

$initial_token = $date_since.$site_id.$shared_secret;

$ascii_version = array();
foreach($i=0; $i < strlen($initial_token); $i++) {
    $ascii_version[] = ord(substr($initial_token,$i,1));
}

$md5_version = md5(join("", $ascii_version));

$hexadecimal_bits = array();
foreach($i=0; $i < strlen($md5_version); $i++) {
   // @todo convert to hexadecimal here?
   $hexadecimal_bits[] = bin2hex(substr($md5_version,$i,1));
}

$result = join("-", $hexadecimal_bits);

Answer 1

I think this will work for you. It looks like the MD5CryptoServiceProvider::ComputeHash method returns an array of 16 bytes, not a string of 32 characters like the normal PHP md5() function. However, PHP’s md5() has a second optional parameter that forces “raw output”, which does correspond to the output of ComputeHash().

$date_since = "2010-02-01";
$site_id = "bash.org";
$shared_secret = "12345";
$initial_token = $date_since.$site_id.$shared_secret;

//get the RAW FORMAT md5 hash
//corresponds to the output of MD5CryptoServiceProvider::ComputeHash
$str = md5($initial_token, true);
$len = strlen($str);
$hex = array();
for($i = 0; $i < $len; $i++) {
    //convert the byte to a hex string representation (left padded with zeros)
    $hex[] = str_pad(dechex(ord($str[$i])), 2, '0', STR_PAD_LEFT);
}
//dump output
echo implode("-",$hex);

//outputs fe-0d-58-fd-5f-3d-83-fe-0f-6a-02-b4-94-0c-aa-7b