Pascal (Lazarus/Delphi)

Ed25519 Key Exchange (Shared Secret)

See more Ed25519 Examples

Demonstrates how to create an Ed25519 shared secret for use in key exchange.

Note: This example requires Chilkat v9.5.0.83 or greater.

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.EdDSA,
  Chilkat.PrivateKey,
  Chilkat.PublicKey;

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

procedure RunDemo;
var
  success: Boolean;
  alicePrivKey: string;
  bobPubKey: string;
  privKey: TPrivateKey;
  pubKey: TPublicKey;
  eddsa: TEdDSA;
  sharedSecret: string;

begin
  success := False;

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

  //  Alice's private key, a:
  //      77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a
  //  Alice's public key, X25519(a, 9):
  //      8520f0098930a754748b7ddcb43ef75a0dbf3a0d26381af4eba4a98eaa9b4e6a
  //  Bob's private key, b:
  //      5dab087e624a8a4b79e17f8b83800ee66f3bb1292618b6fd1c2f8b27ff88e0eb
  //  Bob's public key, X25519(b, 9):
  //      de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f
  //  Their shared secret, K:
  //      4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742

  alicePrivKey := '77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a';
  bobPubKey := 'de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f';

  privKey := TPrivateKey.Create;
  //  This example shows only one way of loading an Ed25519 private key.
  //  Chilkat can load other formats (JWK, PEM, ASN.1 DER, etc.)  
  //  You may do so by calling LoadAnyFormat or LoadAnyFormatFile.
  success := privKey.LoadEd25519(alicePrivKey,'');
  if (success = False) then
    begin
      WriteLn(privKey.LastErrorText);
      Exit;
    end;

  pubKey := TPublicKey.Create;
  success := pubKey.LoadEd25519(bobPubKey);
  if (success = False) then
    begin
      WriteLn(pubKey.LastErrorText);
      Exit;
    end;

  //  Create the shared secret:
  eddsa := TEdDSA.Create;
  sharedSecret := eddsa.SharedSecretENC(privKey,pubKey,'hexlower');
  if (eddsa.LastMethodSuccess = False) then
    begin
      WriteLn(eddsa.LastErrorText);
      Exit;
    end;

  WriteLn('Computed: ' + sharedSecret);
  WriteLn('Expected: 4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742');


  privKey.Free;
  pubKey.Free;
  eddsa.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.