(Delphi DLL) Duplicate openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

1. Creates a SHA256 digest of the contents of the input file
2. Signs the SHA256 digest using the private key.

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, BinData, PrivateKey, Rsa;

...

procedure TForm1.Button1Click(Sender: TObject);
var
pkey: HCkPrivateKey;
success: Boolean;
rsa: HCkRsa;
bdFileData: HCkBinData;
bdSig: HCkBinData;

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

pkey := CkPrivateKey_Create();

// Load the private key from an PEM file:
success := CkPrivateKey_LoadPemFile(pkey,'private.pem');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(pkey));
    Exit;
  end;

rsa := CkRsa_Create();

// Import the private key into the RSA component:
success := CkRsa_ImportPrivateKeyObj(rsa,pkey);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRsa__lastErrorText(rsa));
    Exit;
  end;

// OpenSSL uses big-endian.
CkRsa_putLittleEndian(rsa,False);

// Load the file to be signed.
bdFileData := CkBinData_Create();
success := CkBinData_LoadFile(bdFileData,'in.dat');

bdSig := CkBinData_Create();
success := CkRsa_SignBd(rsa,bdFileData,'sha256',bdSig);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRsa__lastErrorText(rsa));
    Exit;
  end;

// Save the binary signature to a file.
success := CkBinData_WriteFile(bdSig,'signature.sig');
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to write signature.sig.');
    Exit;
  end;

Memo1.Lines.Add('Success.');

CkPrivateKey_Dispose(pkey);
CkRsa_Dispose(rsa);
CkBinData_Dispose(bdFileData);
CkBinData_Dispose(bdSig);

end;