Pascal (Lazarus/Delphi)

RSA SHA256 Signature using Private Key from Java Keystore

See more RSA Examples

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();

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.JavaKeyStore,
  Chilkat.PrivateKey,
  Chilkat.Rsa;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  jks: TJavaKeyStore;
  jksPassword: string;
  privKeyPassword: string;
  caseSensitive: Boolean;
  privKey: TPrivateKey;
  rsa: TRsa;
  binarySignature: TBytes;
  plaintext: string;
  signatureStr: string;

begin
  success := False;

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

  jks := TJavaKeyStore.Create;

  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 = False) then
    begin
      WriteLn(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 := False;
  privKey := TPrivateKey.Create;
  success := jks.PrivateKeyOf(privKeyPassword,'some.alias',caseSensitive,privKey);
  if (success = False) then
    begin
      WriteLn(jks.LastErrorText);
      Exit;
    end;

  //  Establish the RSA object and tell it to use the private key..
  rsa := TRsa.Create;

  success := rsa.UsePrivateKey(privKey);
  if (success = False) then
    begin
      WriteLn(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 = False) then
    begin
      WriteLn(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');
  WriteLn('base64-url RSA signature: ' + signatureStr);


  jks.Free;
  privKey.Free;
  rsa.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.