anchor.diff:      if(System.Environment.UserInteractive) then
           System.Console.Write("Username: ")
           let userName = System.Console.ReadLine()
  -        System.Console.Write("Password: ")
  -        // TODO not cleartext
  -        let password = System.Console.ReadLine()
  +        let password = readPassword "Password: "
           let node = doc.CreateElement("credential")
           node.SetAttribute("source", source)
           node.SetAttribute("username", userName)
  
positive.code:         |> Seq.cast<XmlNode>  
          |> Seq.filter (fun n -> n.Attributes.["source"].Value = source)
          |> Seq.toList
      
  // get the credential from the creedential store for a specific sourcee
  let getFromCredentialStore (source :string)=
      let doc =
  
negative.code: open System.Text
  open System.IO
  
  let credentialStoreDirectory = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "Paket")
  
  let credentialStoreFile = Path.Combine(credentialStoreDirectory, "credentials.xml")
  
  let entropyBytes = Encoding.UTF8.GetBytes("Paket");
  
  // Encrypts a string with a user specific keys
  