Delphi DLL

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

See more OpenSSL Examples

Demonstrates how to duplicate this OpenSSL command:

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

The in.dat file can contain text or binary data of any type. The OpenSSL command does the following:

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

Delphi 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
success: Boolean;
pkey: HCkPrivateKey;
rsa: HCkRsa;
bdFileData: HCkBinData;
bdSig: HCkBinData;

begin
success := False;

// 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 = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(pkey));
    Exit;
  end;

rsa := CkRsa_Create();

// Import the private key into the RSA component:
success := CkRsa_UsePrivateKey(rsa,pkey);
if (success = False) 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 = False) 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;