One of the changes in the RDP 6 client is that it is no longer possible to save passwords in RDP files. This does not seem to be the most popular feature of the RDP 6 client. Microsoft has deemed it necessary perhaps even because a fellow Dutchman, Remko Weijnen, found out ow RDP passwords were encrypted and decrypted in the RDP 5.2 client.

In a post of about half a year ago Remko mentioned that he had figured out how the RDP (<5.2) saves passwords. He details on how he found out how the RDP client saves the password and even supplies a tool to to encrypt and decrypt rdp passwords.

Today Remko posted a followup in where he explains how the RDP client encrypts the password to the full 1329 bytes.