(Delphi DLL) Ed25519ph Sign and Verify

Demonstrates how to create an Ed25519ph signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.91 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.

// Use the following test vector from https://www.rfc-editor.org/rfc/rfc8032#page-30

//    -----TEST abc
// 
//    ALGORITHM:
//    Ed25519ph
// 
//    SECRET KEY:
//    833fe62409237b9d62ec77587520911e
//    9a759cec1d19755b7da901b96dca3d42
// 
//    PUBLIC KEY:
//    ec172b93ad5e563bf4932c70e1245034
//    c35467ef2efd4d64ebf819683467e2bf
// 
//    MESSAGE (length 3 bytes):
//    616263
// 
//    SIGNATURE:
//    98a70222f0b8121aa9d30f813d683f80
//    9e462b469c7ff87639499bb94e6dae41
//    31f85042463c2a355a2003d062adf5aa
//    a10b8c61e636062aaad11c2a26083406

privKeyHex := '833fe62409237b9d62ec77587520911e9a759cec1d19755b7da901b96dca3d42';
pubKeyHex := 'ec172b93ad5e563bf4932c70e1245034c35467ef2efd4d64ebf819683467e2bf';

privKey := CkPrivateKey_Create();
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_AppendEncoded(bd,'616263','hex');

eddsa := CkEdDSA_Create();
// Indicate we want the Ed25519ph instance.
CkEdDSA_putAlgorithm(eddsa,'Ed25519ph');

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

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

// The expected output is: 98a70222f0b8121aa9d30f813d683f80....

// 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 Ed25519ph signature is verified!');

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

end;