Delphi ActiveX

Encrypt with Chilkat, Decrypt with OpenSSL

See more OpenSSL Examples

Demonstrates how to RSA encrypt a string using Chilkat, and then shows the corresponding OpenSSL command to RSA decrypt. The OpenSSL command to decrypt is as follows:

openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

Delphi ActiveX

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
success: Integer;
rsa: TChilkatRsa;
key: TPublicKey;
strToEncrypt: WideString;
usePrivateKey: Integer;
encryptedBytes: Array of Byte;
fac: TCkFileAccess;

begin
success := 0;

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

rsa := TChilkatRsa.Create(Self);

// Note: RSA encryption uses the public key.  
// RSA decryption uses the private key.
// The reason is that the public key can be freely provided to anybody.  This allows anybody
// to send an encrypted message to the private key owner, and only the private key owner 
// can decrypt.
key := TPublicKey.Create(Self);

// Load an RSA public key from a PEM file:
success := key.LoadFromFile('qa_data/pem/VP_Public.pem');
if (success = 0) then
  begin
    Memo1.Lines.Add(key.LastErrorText);
    Exit;
  end;

// Load the public key into the RSA object.
success := rsa.UsePublicKey(key.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

strToEncrypt := '00000000;XYZ2-3BHQ-ABCD-MMVV;6MY1-GHJK-9LRR;0';

// The LittleEndian property is 0 by default, but it is set here
// anyway to show that LittleEndian byte ordering is required for OpenSSL compatibility.
rsa.LittleEndian := 0;

usePrivateKey := 0;

encryptedBytes := rsa.EncryptString(strToEncrypt,usePrivateKey);
if (rsa.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

// The OpenSSL command to decrypt would be this:
// openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

fac := TCkFileAccess.Create(Self);
success := fac.WriteEntireFile('qa_output/rsa_encrypted.bin',encryptedBytes);
if (success = 0) then
  begin
    Memo1.Lines.Add(fac.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('RSA Encryption Succeeded.');
end;