(Delphi ActiveX) RSA SHA256 Signature using Private Key from Java Keystore

Signs plaintext using RSA SHA256 using a key from a Java keystore.

Duplicatest this code:

KeyStore keystore; // key repository for keys containing signature certificate
String alias; // alias for the certificate in the key repository
String password; // password for the certificate's private key
String plaintext; // text being signed


Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign((PrivateKey) keystore.getKey(alias, password.toCharArray()));
signature.update(plaintext.getBytes("UTF-8"));
byte[] rsa_text= signature.sign();

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
jks: TChilkatJavaKeyStore;
jksPassword: WideString;
success: Integer;
privKeyPassword: WideString;
caseSensitive: Integer;
privKey: IPrivateKey;
rsa: TChilkatRsa;
binarySignature: Array of Byte;
plaintext: WideString;
signatureStr: WideString;

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

jks := TChilkatJavaKeyStore.Create(Self);

jksPassword := 'secret';

// Load the Java keystore from a file.  The JKS file password is used
// to verify the keyed digest that is found at the very end of the keystore.
// It verifies that the keystore has not been modified.
success := jks.LoadFile(jksPassword,'qa_data/jks/sample_secret.jks');
if (success <> 1) then
  begin
    Memo1.Lines.Add(jks.LastErrorText);
    Exit;
  end;

// Get the private key from the JKS.
// The private key password may be different than the file password.
privKeyPassword := 'secret';
caseSensitive := 0;
privKey := jks.FindPrivateKey(privKeyPassword,'some.alias',caseSensitive);
if (jks.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(jks.LastErrorText);
    Exit;
  end;

// Establish the RSA object and tell it to use the private key..
rsa := TChilkatRsa.Create(Self);

success := rsa.ImportPrivateKeyObj(privKey);

if (success <> 1) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

// Indicate we'll be signing the utf-8 byte representation of the string..
rsa.Charset := 'utf-8';

// Sign some plaintext using RSA-SHA256

plaintext := 'this is the text to be signed';
binarySignature := rsa.SignString(plaintext,'SHA256');
if (rsa.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

// Alternatively, if the signature is desired in some encoded string form,
// such as base64, base64-url, hex, etc.
rsa.EncodingMode := 'base64-url';
signatureStr := rsa.SignStringENC(plaintext,'SHA256');
Memo1.Lines.Add('base64-url RSA signature: ' + signatureStr);
end;