MD5在VB.net和PHP之间进行哈希处理

Question

Answered with the help of @JonSkeet

Given this code:

    Dim data1ToHash As Byte() = (New UnicodeEncoding).GetBytes(input)
    ' 2. Hash the byte array
    Dim hashvalue1 As Byte() = CType(CryptoConfig.CreateFromName("MD5"), HashAlgorithm).ComputeHash(data1ToHash)

Shouldn't this PHP produce the correct hash?

$md5 = (md5(utf8_encode($signature), true));

I tried, but the md5sums aren't matching up. I assumed it was encoding, but perhaps it has to do with the byte array, can anyone shed some light on this? FYI I can't change the VB

To compare the results:

in .Net

For Each b As Byte In hashvalue1
  tb.Text = tb.Text & b.ToString() & ","
Next
tb.Text = tb.Text.Trim(",")

in PHP

print_r(unpack('C*', pack('H*', md5($signature))))

as per another question

Answer 1

It's not clear how you're comparing the results, but the encoding is *definitely a problem - you're using UTF-16 in the VB code, and UTF-8 in the PHP. You can change the VB code like this:

Dim data1ToHash As Byte() = Encoding.UTF8.GetBytes(input)

The MD5 part can also be simplified, giving this result:

Dim unhashed As Byte() = Encoding.UTF8.GetBytes(input)
Dim hashed As Byte() = MD5.Create().ComputeHash(unhashed)

EDIT: If you can't change the VB, you need to change the PHP to use UTF-16, potentially with mbstring as suggested in comments. You'll need to know what the existing encoding is, of course...

Answer 2

The solution had to do with byte ordering: .NET in UTF-16 was Little Endian, whereas PHP's default UTF-16 encoding is Big Endian. So the answer is:

mb_internal_encoding('UTF-8');
$string = mb_convert_encoding($signature, 'UTF-16LE', 'UTF-8');
$encoded_signature = base64_encode(md5($string, true));

To verify, I compared the UTF-16 encoded bytes in PHP and .NET:

print_r(unpack('C*', $string));

Just that simple. Thanks to everyone who helped, especially @JonSkeet.