(Delphi ActiveX) RSA Encrypt Bytes to Base64 and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt bytes to base64 and the reverse.

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
pubKey: TPublicKey;
success: Integer;
rsa: TChilkatRsa;
prng: TChilkatPrng;
keyBytes: Array of Byte;
encryptedB64: WideString;
privKey: TPrivateKey;
password: WideString;
decBytes: Array of Byte;

begin
// The RSA public key is used for encryption, and the private key for decryption.

// The public key's role is to make encryption accessible to anyone while ensuring that
// only the private key holder can decrypt the messages.
// The public key is designed to be widely distributed so anyone can use it to encrypt messages
// intended for the owner of the private key.

// Load our 2048-bit RSA public key.
pubKey := TPublicKey.Create(Self);
// In all Chilkat methods expecting a path, you pass either absolute or relative paths.
success := pubKey.LoadFromFile('qa_data/rsaKeys/myTestRsaPublic.pem');
if (success = 0) then
  begin
    Memo1.Lines.Add(pubKey.LastErrorText);
    Exit;
  end;

rsa := TChilkatRsa.Create(Self);

// Tell RSA to use the public key.
rsa.ImportPublicKeyObj(pubKey.ControlInterface);

// RSA encryption is for small amounts of data, on the order of 200 bytes or less.
// The maximum number of bytes that can be RSA encrypted depends
// on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
// For specific limits, see: RSA Encryption Maximum Number of Bytes

// A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
prng := TChilkatPrng.Create(Self);

keyBytes := prng.GenRandomBytes(32);

rsa.EncodingMode := 'base64';
encryptedB64 := rsa.EncryptBytesENC(keyBytes,0);

Memo1.Lines.Add('Result:');
Memo1.Lines.Add(encryptedB64);

// Sample output:
// hTTV4Lbmm2V7NCw/HaoJL8Aq/MM/HXblQnjitrF9HY1zBlISwui2jGVVZDtZcZ/rICOpPw44w8Qb8AswFVE1sryydmNEvcIfYAp/xgdBPXBERAS0y4AoEzUfuC5TJmJFvnFkl2lX8GAclANfcTik38V+k3EXu5wPzHKNFb07c6jnwh3Jm4f3PRUhmmB2NO5kSWqHsx0dNglOTq5BUZx34nxlXL5G8d7mXqITsUtrOHXAO/Gb7IrvB81Xk2vc5p4yHhiY/rFTHTTmZyzte2qHGm7V6xPRNURjiivnMY2jQU0Um1JKQcAiSe8Suwvd2LXP5PIhl71VLgO+fokjnynfRg==

// ------------------------------------------------------------------------------------------------------------------------
// Let's decrypt, which requires the matching private key...

// Load the matching 2048-bit RSA private key.
privKey := TPrivateKey.Create(Self);
password := 'secret';
success := privKey.LoadAnyFormatFile('qa_data/rsaKeys/myTestRsaPrivate.pem',password);
if (success = 0) then
  begin
    Memo1.Lines.Add(privKey.LastErrorText);
    Exit;
  end;

// Tell the RSA object to use the private key.
rsa.ImportPrivateKeyObj(privKey.ControlInterface);

decBytes := rsa.DecryptBytesENC(encryptedB64,1);
if (success = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Success.');
end;