(Delphi DLL) Ed25519 Sign and Verify

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

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

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, EdDSA, BinData, PrivateKey, PublicKey;

...

procedure TForm1.Button1Click(Sender: TObject);
var
privKeyHex: PWideChar;
pubKeyHex: PWideChar;
privKey: HCkPrivateKey;
success: Boolean;
bd: HCkBinData;
eddsa: HCkEdDSA;
hexSig: PWideChar;
pubKey: HCkPublicKey;
bVerified: Boolean;

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

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

privKey := CkPrivateKey_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 := CkPrivateKey_LoadEd25519(privKey,privKeyHex,pubKeyHex);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

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

eddsa := CkEdDSA_Create();
hexSig := CkEdDSA__signBdENC(eddsa,bd,'hexlower',privKey);

Memo1.Lines.Add('signature = ' + hexSig);

// The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

// Verify the signature..
pubKey := CkPublicKey_Create();
success := CkPublicKey_LoadEd25519(pubKey,pubKeyHex);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPublicKey__lastErrorText(pubKey));
    Exit;
  end;

bVerified := CkEdDSA_VerifyBdENC(eddsa,bd,hexSig,'hexlower',pubKey);
if (bVerified = False) then
  begin
    Memo1.Lines.Add(CkEdDSA__lastErrorText(eddsa));
    Memo1.Lines.Add('Failed to verify the signature.');
    Exit;
  end;

Memo1.Lines.Add('The Ed25519 signature is verified!');

CkPrivateKey_Dispose(privKey);
CkBinData_Dispose(bd);
CkEdDSA_Dispose(eddsa);
CkPublicKey_Dispose(pubKey);

end;