MD5 Code Conversion in VB. NET

Dim MD5 as new md5cryptoserviceprovider
Dim username as byte () = (New asciiencoding). getbytes (textbox1.text)
Dim mdstring as string, mdstring1 as string, mdstring2 as string
Dim I as integer
'Convert to a hash byte array
Dim mdbyte as byte () = md5.computehash (username)
Mdstring = system. bitconverter. tostring (mdbyte)
For I = 1 to 15
Mdstring = mdstring. substring (0, 2 * I) & mdstring. substring (3 + 2 * (I-1), 47-I * 3)
Next
'Mdstring = system. bitconverter. tostring (mdbyte)
'Mdstring = (New asciiencoding). getstring (mdbyte)
Textbox2.text = mdstring