ARC4 Encryption (ARCFOUR)

ARC4 (ARCFOUR) encryption. The Chilkat encryption component supports the ARC4 streaming encryption algorithm.

Download Chilkat Crypt ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATCRYPT2Lib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: TChilkatCrypt2;
success: Integer;
keyHex: String;
encStr: String;
decStr: String;

begin
crypt := TChilkatCrypt2.Create(Self);

success := crypt.UnlockComponent('Anything for 30-day trial');
if (success <> 1) then
  begin
    ShowMessage('Crypt component unlock failed');

  end;

//  Set the encryption algorithm = "arc4"
crypt.CryptAlgorithm := 'arc4';

//  KeyLength may range from 1 byte to 256 bytes.
//  (i.e. 8 bits to 2048 bits)
//  ARC4 key sizes are typically in the range of
//  40 to 128 bits.
//  The KeyLength property is specified in bits:
crypt.KeyLength := 128;

//  Note: The PaddingScheme and CipherMode properties
//  do not apply w/ ARC4.  ARC4 does not encrypt in blocks --
//  it is a streaming encryption algorithm. The number of output bytes
//  is exactly equal to the number of input bytes.

//  EncodingMode specifies the encoding of the output for
//  encryption, and the input for decryption.
//  It may be "hex", "url", "base64", or "quoted-printable".
crypt.EncodingMode := 'hex';

//  Note: ARC4 does not utilize initialization vectors.  IV's only
//  apply to block encryption algorithms.

//  The secret key must equal the size of the key.
//  For 128-bit encryption, the binary secret key is 16 bytes.
keyHex := '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F';
crypt.SetEncodedKey(keyHex,'hex');

//  Encrypt a string...
//  The output length is exactly equal to the input.  In this
//  example, the input string is 44 chars (ANSI bytes) so the
//  output is 44 bytes -- and when hex encoded results in an
//  88-char string (2 chars per byte for the hex encoding).
encStr := crypt.EncryptStringENC('The quick brown fox jumps over the lazy dog.');
ShowMessage(encStr);

//  Now decrypt:
decStr := crypt.DecryptStringENC(encStr);
ShowMessage(decStr);
end;