(Delphi ActiveX) RSA Decrypt using PEM

This example demonstrates decryping RSA encrypted data that is base64 encoded. It uses a private key loaded from a PEM file.

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
rsa: TChilkatRsa;
key: TPrivateKey;
success: Integer;
encryptedStr: WideString;
usePrivateKey: Integer;
decryptedStr: WideString;

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

rsa := TChilkatRsa.Create(Self);

key := TPrivateKey.Create(Self);

// Load an RSA private key from an unencrypted PEM file:
// (To load from an encrypted PEM file, call LoadEncryptedPemFile instead.)

success := key.LoadPemFile('qa_data/rsa/decryptTest/priv.pem');
if (success <> 1) then
  begin
    Memo1.Lines.Add(key.LastErrorText);
    Exit;
  end;

// Make the key available to the RSA object
success := rsa.ImportPrivateKeyObj(key.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

encryptedStr := 'pP9XFJEsGgxPNHEgNiLB5H5ksCOXDk/G49BPTog1jKLAhYofV4UTH5k2TOYiqRnDnKs8+8uPoN/IxdiGXvuYG8HRzN0HtkhoZO/AxeyaB9S7eddCUlT0Pl2PEB2yQ9HG5rM7jqYOD6MAM4cuX7hqT8fa8tbzJzmBwdfFDBz94bwQjULHiO+gklIBC4vhkXT4yjuvEjxTAKU6tJeZYkBooJNdS/vE5RZRpuF6bGZU41Qc17qFR+iReBq+9f8IMmw8WR8fMbOCaygOfFS1nw7JVsIMGsAIXS8rUaJ/2DfGPfQx5HCiVtTOreGYRUI3esAQjnvUCnavZyQgs53nl7e2aA==';

rsa.EncodingMode := 'base64';

usePrivateKey := 1;
decryptedStr := rsa.DecryptStringENC(encryptedStr,usePrivateKey);

Memo1.Lines.Add('Decrypted:');
Memo1.Lines.Add(decryptedStr);
end;