References:
> QSG code example provided with the installer

After installation, a group PyBridge will appear in the Tool Palette of Delphi, where you can find the new component TPBRSA

New component TPBRSA can be found in the Tool Palette under PyBridge group

Place TPBRSA onto the form and set up its main properties:

• OpenSSL – the path to the openssl.exe library file supplied as part of the component.
• PrivateKey – the private key to be used. Calling a “PBRSA1.GenerateKeys” command will fill this field automatically. In the trial version this value is predefined.
• PublicKey – the public key to be used. Calling a “PBRSA1.GenerateKeys” command will fill this field automatically. In the trial version this value is predefined.

Now PBRSA is ready to be used. To demonstrate how it works, let’s create a simple application for generating keys, encryption, and decryption.
Add the corresponding buttons and Memos to the form to display:

• generated keys: public and private
• the original text to be encoded
• code obtained by encryption using the public key
• text recovered using the private key
• error messages

PBRSA encryption / decryption application layout

Instead of manually entering both private and public keys you may use “PBRSA1.GenerateKeys” command somewhere in your code (e.g. with a separate button). Keys generated by “PBRSA1.GenerateKeys” command will overwrite the corresponding PBRSA1 object properties. If you have a trial version you don’t need to do this, as the keys are predefined.

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PBRSA1.GenerateKeys; //no need if the trial version
PrivateKeyMemo.Text := PBRSA1.PrivateKey;
PublicKeyMemo.Text := PBRSA1.PublicKey;

Encode the message from the “Data To Crypt” field. For encoding, the key specified by the PBRSA1.PublicKey property is used. 

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procedure TRSADemo.PublicEncryptButtonClick(Sender: TObject);
var
  ResultStr1, ResultStr2: AnsiString;
  ErrorMessage: String;
begin
  CryptedDataMemo.Clear;
  DecryptedDataMemo.Clear;
  ErrorMemo.Clear;

  ResultStr1 := AnsiString(DataToCryptMemo.Text);

  if PBRSA1.PublickEncrypt(ResultStr1, ResultStr2, ErrorMessage) then
    begin
      CryptedDataMemo.Text := ResultStr2;
      astr := ResultStr2;
    end
  else
    begin
      ErrorMemo.Text := ErrorMessage;
    end;
end;

Decrypt the previously encoded message with the private key. For decoding, the key specified by the PBRSA1.PublicKey property is used. 

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procedure TRSADemo.PrivateDecryptButtonClick(Sender: TObject);
var
  ResultStr1, ResultStr2: AnsiString;
  ErrorMessage: String;
begin
  DecryptedDataMemo.Clear;
  ErrorMemo.Clear;

  ResultStr1 := astr;

  if PBRSA1.PrivateDecrypt(ResultStr1, ResultStr2, ErrorMessage) then
    begin
      DecryptedDataMemo.Text := ResultStr2;
    end
  else
    begin
      ErrorMemo.Text := ErrorMessage;
    end;
end;

Start the program,  fill the “Data to Crypt” field with the text you want to encrypt and click the “Public Encrypt” button. A message encrypted with the “Public Key” will appear in the “Crypted Data” field.

Click the “Private Decrypt” button. A decrypted message will appear in the “Decrypted Data” field. Make sure that it matches the original.

This example demonstrates how you can easily and quickly generate RSA keys, perform encryption and decryption with a help of PBRSA component. Now you can also enjoy the full power of PBRSA in your applications!