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unit Crypt32;
{
*************************************************************************
* Name:		Crypt32.Pas				  		*
* Description:	32 bits encode/decode module			  	*
*	        2^96 variants it is very high to try hack		*
* Purpose:  	Good for encrypting passwors and text			*
* Security: 	avoid use StartKey less than 256			*
*		if it use only for internal use you may use default 	*
*		key, but MODIFY unit before compiling			*
* Call:		Encrypted := Encrypt(InString,StartKey,MultKey,AddKey)	*
*		Decrypted := Decrypt(InString,StartKey)		  	*
* Parameters:	InString  = long string (max 2 GB) that need to encrypt	*
*		decrypt	  						*
*		MultKey		= MultKey key				*
*		AddKey		= Second key		        	*
*		StartKey	= Third key				*
*		(posible use defaults from interface)			*
* Return:	OutString	= result string				*
* Editor:	Besr viewed with Tab stops = 2, Courier new		*
* Started:	01.08.1996						*
* Revision:	22.05.1997 - ver.2.01 converted from Delphi 1		*
*		and made all keys as parameters, before only start key	*
* Platform:	Delphi 2.0, 3.0 				  	*
* 		work in Delphi 1.0, 2^48 variants, 0..255 strings	*
* Author:	Anatoly Podgoretsky				  	*
* 		Base alghoritm from Borland				*
* Address:	Vahe 4-31, Johvi, Estonia, EE2045, tel. 61-142    	*
*		kvk@estpak.ee					  	*
* Status:	Freeware, but any sponsor help will be appreciated here	*
*		need to buy books, shareware products, tools etc	*
*************************************************************************
* Modified:     Supports Delphi 1.0 & 2.0                         	*
*               Overflow checking removed                         	*
* By:           Martin Djernæs                                    	*
* e-mail:       djernaes@einstein.ot.dk                           	*
* web:          einstein.ot.dk/~djernaes                          	*
*************************************************************************
}
interface

const
  StartKey	= 981;  	{Start default key}
  MultKey	  = 12674;	{Mult default key}
  AddKey	  = 35891;	{Add default key}

function Encrypt(const InString:string; StartKey,MultKey,AddKey:Integer): string;
function Decrypt(const InString:string; StartKey,MultKey,AddKey:Integer): string;

implementation

{$R-}
{$Q-}
{*******************************************************
 * Standard Encryption algorithm - Copied from Borland *
 *******************************************************}
function Encrypt(const InString:string; StartKey,MultKey,AddKey:Integer): string;
var
  I : Byte;
begin
  Result := '';
  for I := 1 to Length(InString) do
  begin
    Result := Result + CHAR(Byte(InString[I]) xor (StartKey shr 8));
    StartKey := (Byte(Result[I]) + StartKey) * MultKey + AddKey;
  end;
end;
{*******************************************************
 * Standard Decryption algorithm - Copied from Borland *
 *******************************************************}
function Decrypt(const InString:string; StartKey,MultKey,AddKey:Integer): string;
var
  I : Byte;
begin
  Result := '';
  for I := 1 to Length(InString) do
  begin
    Result := Result + CHAR(Byte(InString[I]) xor (StartKey shr 8));
    StartKey := (Byte(InString[I]) + StartKey) * MultKey + AddKey;
  end;
end;
{$R+}
{$Q+}

end.

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