Pack function in C#

hello,

Our PHP dev (who has since left) uses the pack function to turn a base64 string into a binary blob (?):

$blob = pack("H*", $postBase64Data);

Does anyone know what the above is doing? I need to translate that to C# terms, which I thought was getting the eqivalent of the bytes:

byte[] blob = ASCIIEncoding.UTF8.GetBytes(postedData);

But this may not be right.

Sym