Pascal (Lazarus/Delphi)

ChaCha20 Encryption

See more Encryption Examples

Demonstrates ChaCha20 encryption and decryption. (Introduced in Chilkat v9.5.0.55) This example duplicates the results of Test Vector #3 for ChaCha20 Encryption in RFC 7539. Pascal (Lazarus/Delphi)

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;
  ivHex: string;
  keyHex: string;
  plainText: 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 to chacha20
  //  chacha20 is a stream cipher, and therefore no cipher mode applies.
  crypt.CryptAlgorithm := 'chacha20';

  //  The key length for chacha20 is always 256-bits.
  crypt.KeyLength := 256;

  //  Note: "padding" only applies to block encryption algorithmns.
  //  Since chacha20 is a stream cipher, there is no padding and the output
  //  number of bytes is exactly equal to the input.

  //  EncodingMode specifies the encoding of the output for
  //  encryption, and the input for decryption.
  //  Valid modes are (case insensitive) "Base64", "modBase64", "Base32", "Base58", "UU", 
  //  "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", 
  //  "Q", "B", "url_oauth", "url_rfc1738", "url_rfc2396", and "url_rfc3986".
  crypt.EncodingMode := 'hex';

  //  The inputs to ChaCha20 encryption, specified by RFC 7539, are:
  //  1) A 256-bit secret key.
  //  2) A 96-bit nonce.
  //  3) A 32-bit initial count.
  //  The IV property is used to specify the chacha20 nonce.
  //  For a 96-bit nonce, the IV should be 12 bytes in length.
  //  
  //  Note: Some implementations of chacha20, such as that used internally by SSH,
  //  use a 64-bit nonce and 64-bit count.  To do chacha20 encryption in this way,
  //  simply provide 8 bytes for the IV instead of 12 bytes.  Chilkat will then automatically
  //  use 8 bytes (64-bits) for the count. 

  //  This example duplicates Test Vector #3 (for ChaCha20 encryption) from RFC 7539.
  ivHex := '000000000000000000000002';
  crypt.SetEncodedIV(ivHex,'hex');

  crypt.InitialCount := 42;

  keyHex := '1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0';
  crypt.SetEncodedKey(keyHex,'hex');

  plainText := '''Twas brillig, and the slithy toves' + #10 + 'Did gyre and gimble in the wabe:' + #10 + 'All mimsy were the borogoves,' + #10 + 'And the mome raths outgrabe.';

  encStr := crypt.EncryptStringENC(plainText);
  WriteLn(encStr);

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

  //  Here is the Test Vector data copied from RFC 7539

  //   Test Vector #3:
  //   ==============
  //  
  //   Key:
  //   000  1c 92 40 a5 eb 55 d3 8a f3 33 88 86 04 f6 b5 f0  ..@..U...3......
  //   016  47 39 17 c1 40 2b 80 09 9d ca 5c bc 20 70 75 c0  G9..@+....\. pu.
  //  
  //   Nonce:
  //   000  00 00 00 00 00 00 00 00 00 00 00 02              ............
  //  
  //   Initial Block Counter = 42
  //  
  //   Plaintext:
  //   000  27 54 77 61 73 20 62 72 69 6c 6c 69 67 2c 20 61  'Twas brillig, a
  //   016  6e 64 20 74 68 65 20 73 6c 69 74 68 79 20 74 6f  nd the slithy to
  //   032  76 65 73 0a 44 69 64 20 67 79 72 65 20 61 6e 64  ves.Did gyre and
  //   048  20 67 69 6d 62 6c 65 20 69 6e 20 74 68 65 20 77   gimble in the w
  //   064  61 62 65 3a 0a 41 6c 6c 20 6d 69 6d 73 79 20 77  abe:.All mimsy w
  //   080  65 72 65 20 74 68 65 20 62 6f 72 6f 67 6f 76 65  ere the borogove
  //   096  73 2c 0a 41 6e 64 20 74 68 65 20 6d 6f 6d 65 20  s,.And the mome
  //   112  72 61 74 68 73 20 6f 75 74 67 72 61 62 65 2e     raths outgrabe.
  //  
  //   Ciphertext:
  //   000  62 e6 34 7f 95 ed 87 a4 5f fa e7 42 6f 27 a1 df  b.4....._..Bo'..
  //   016  5f b6 91 10 04 4c 0d 73 11 8e ff a9 5b 01 e5 cf  _....L.s....[...
  //   032  16 6d 3d f2 d7 21 ca f9 b2 1e 5f b1 4c 61 68 71  .m=..!...._.Lahq
  //   048  fd 84 c5 4f 9d 65 b2 83 19 6c 7f e4 f6 05 53 eb  ...O.e...l....S.
  //   064  f3 9c 64 02 c4 22 34 e3 2a 35 6b 3e 76 43 12 a6  ..d.."4.*5k>vC..
  //   080  1a 55 32 05 57 16 ea d6 96 25 68 f8 7d 3f 3f 77  .U2.W....%h.}??w
  //   096  04 c6 a8 d1 bc d1 bf 4d 50 d6 15 4b 6d a7 31 b1  .......MP..Km.1.
  //   112  87 b5 8d fd 72 8a fa 36 75 7a 79 7a c1 88 d1     ....r..6uzyz...


  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.