Lazarus Pascal

ARC4 Encryption (ARCFOUR)

See more Encryption Examples

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

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  crypt: TCrypt2;
  keyHex: string;
  encStr: string;
  decStr: string;

begin
  //  This example assumes the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  crypt := TCrypt2.Create;

  //  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.');
  WriteLn(encStr);

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


  crypt.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.