Algorithm to decode Windows keys

[samrocketman]

• GetXPKey / GetVistaKey - Get key for a given operating system. It calls GetMSDPID3.
• GetMSDPID3 - Get Microsoft Digital Product Identification number. It calls DecodeMSKey.
• DecodeMSKey - decodes MS product key.

ekeyfinder/Main.pas

Lines 1961 to 2006 in d8e5904

	function TfrmMain.DecodeMSKey(const HexSrc: array of byte; const ID: boolean): string;
	const
	Digits: array[0..23] of char =
	('B', 'C', 'D', 'F', 'G', 'H', 'J', 'K', 'M', 'P', 'Q', 'R', 'T',
	'V', 'W', 'X', 'Y', '2', '3', '4', '6', '7', '8', '9');
	iDecodedLen: integer = 29; // Length of Decoded Product Key
	iEncodedLen: integer = 15;
	// Length of Encoded Product Key in Bytes (An total of 30 in chars)
	var
	HexDigitalPID: array of cardinal;
	Des: array[0..30] of char; // Length of Decoded Product Key + 1
	iStartOffset: integer;
	iEndOffset: integer;
	I: integer;
	N: integer;
	HN: cardinal;
	Value: cardinal;
	begin
	if ID then
	iStartOffset := $328
	else
	iStartOffset := $34;
	iEndOffset := iStartOffset + 15;
	Result := '';
	SetLength(HexDigitalPID, iDecodedLen);
	for I := iStartOffset to iEndOffset do
	HexDigitalPID[I - iStartOffSet] := HexSrc[I];
	for I := iDecodedLen - 1 downto 0 do
	if (((I + 1) mod 6) = 0) then
	Des[I] := '-'
	else
	begin
	HN := 0;
	for N := iEncodedLen - 1 downto 0 do
	begin
	Value := (HN shl 8) or HexDigitalPID[N];
	HexDigitalPID[N] := Value div 24;
	HN := Value mod 24;
	end;
	Des[I] := Digits[HN];
	end;
	Des[iDecodedLen] := Chr(0);
	Result := StrPas(Des);
	end; // TfrmMain.DecodeMSKey