Pascal (Lazarus/Delphi)

Ed25519 Sign and Verify

See more Ed25519 Examples

Demonstrates how to create an Ed25519 signature, and then to verify it.

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.BinData,
  Chilkat.PrivateKey,
  Chilkat.PublicKey;

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

procedure RunDemo;
var
  success: Boolean;
  privKeyHex: string;
  pubKeyHex: string;
  privKey: TPrivateKey;
  bd: TBinData;
  eddsa: TEdDSA;
  hexSig: string;
  pubKey: TPublicKey;
  bVerified: Boolean;

begin
  success := False;

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

  privKeyHex := '1498b5467a63dffa2dc9d9e069caf075d16fc33fdd4c3b01bfadae6433767d93';
  pubKeyHex := 'b7a3c12dc0c8c748ab07525b701122b88bd78f600c76342d27f25e5f92444cde';

  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(privKeyHex,pubKeyHex);
  if (success = False) then
    begin
      WriteLn(privKey.LastErrorText);
      Exit;
    end;

  //  The data to be signed...
  bd := TBinData.Create;
  bd.AppendString('Message for Ed25519 signing','utf-8');

  eddsa := TEdDSA.Create;
  hexSig := eddsa.SignBdENC(bd,'hexlower',privKey);

  WriteLn('signature = ' + hexSig);

  //  The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

  //  Verify the signature..
  pubKey := TPublicKey.Create;
  success := pubKey.LoadEd25519(pubKeyHex);
  if (success = False) then
    begin
      WriteLn(pubKey.LastErrorText);
      Exit;
    end;

  bVerified := eddsa.VerifyBdENC(bd,hexSig,'hexlower',pubKey);
  if (bVerified = False) then
    begin
      WriteLn(eddsa.LastErrorText);
      WriteLn('Failed to verify the signature.');
      Exit;
    end;

  WriteLn('The Ed25519 signature is verified!');


  privKey.Free;
  bd.Free;
  eddsa.Free;
  pubKey.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.