DynDNS update password decoder

aluigi · **Posted:** 16 Mar 2009 03:58

the algorithm is so simple that doesn't deserve a tool specific for it.

the program about I refer is DynDNS Update Client: http://www.dyndns.com/support/clients/windows.html
the password is saved in the file config.dyndns located in %APPDATA%\DynDNS\Updater or "C:\Documents and Settings\All Users\Application Data\DynDNS\Updater"

the saved password is in hex format and is simply XORed with the word t6KzXhCh

a quick example of decoding it on the fly is through the usage of my Xor and hex2byte tools:

echo 194f3b1b2b1b34070652 | hex2byte - | xor - - t6KzXhCh

(194f3b1b2b1b34070652 is the encoded hex string of "mypassword")

Kill3r7 · **Joined:** 03 May 2009 05:10 **Posts:** 16

little bit more explanation please?
cause i tried with my normal xor function in delphi but it didnt work

Code:

function XOREncryption(Input:String):String;
const
 Key = 't6KzXhCh';
var
 Y, Z : Integer;
 B : Byte;
begin
 Z := 1;
 for Y := 1 to Length(Input) do
 begin
  B := (Ord(Input[Y]) and $0f) xor (Ord(Key[Z]) and $0f);
  B := B xor 10 ;
  Input[Y] := Char((Ord(Input[Y]) and $f0)+B);
  Inc(Z);
  If Z > Length(Key) then Z:=1;
 end;
 Result := Input;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
 MyByteStr:String;
begin
 MyByteStr := IntToHex($194f3b1b2b1b34070652,2);
 Memo1.Text := XOREncryption(MyByteStr);
end;

SomaFM · **Joined:** 16 Aug 2007 06:25 **Posts:** 367

After you go from hex to byte, make sure to xor the first byte with the first byte in the key, 2nd byte with the 2nd byte in the key, and keep going in a loop until you reach the end of your XORd string. So using the key "t6KzXhCh" here is an example:

m ^ t
y ^ 6
p ^ K
a ^ z
s ^ X
s ^ h
w ^ C
o ^ h
r ^ t
d ^ 6

Of course "mypassword" above would actually be the xor'd password (after you go from hex > byte), but since it's just encoding/decoding it works both ways. Here is a method of doing this in php: http://pastebin.com/f73185567

I don't know Delphi so I can't help with your code, sorry

Kill3r7 · **Joined:** 03 May 2009 05:10 **Posts:** 16

edit : thanks all fixed :D

Luigi Auriemma

DynDNS update password decoder