(Delphi ActiveX) RSAES-OAEP Encrypt String with AES-128 Content Encryption and SHA256

Encrypts a string using RSAES-OAEP with SHA256 and AES-128 content encryption to produce PKCS7 output (base64 encoded).

Note: This example requires Chilkat v9.5.0.67 or greater.

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
sb: TChilkatStringBuilder;
i: Integer;
cert: TChilkatCert;
success: Integer;
crypt: TChilkatCrypt2;
base64Pkcs7: WideString;

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

// First build a string to be encrypted
sb := TChilkatStringBuilder.Create(Self);
i := 1;
while i < 25 do
  begin
    sb.AppendInt(i);
    sb.Append(' the quick brown fox jumped over the lazy dog.' + #13#10);
    i := i + 1;
  end;

Memo1.Lines.Add(sb.GetAsString());

// The string to be encrypted looks like this:

// 1 the quick brown fox jumped over the lazy dog.
// 2 the quick brown fox jumped over the lazy dog.
// 3 the quick brown fox jumped over the lazy dog.
// 4 the quick brown fox jumped over the lazy dog.
// 5 the quick brown fox jumped over the lazy dog.
// 6 the quick brown fox jumped over the lazy dog.
// ...

// Load a digital certificate. 
// We don't need the private key for encryption.
// Only the public key is needed (which is included in a certificate).
cert := TChilkatCert.Create(Self);
success := cert.LoadFromFile('qa_data/rsaes-oaep/cert.pem');
if (success <> 1) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

crypt := TChilkatCrypt2.Create(Self);

// Tell the crypt object to use the certificate.
crypt.SetEncryptCert(cert.ControlInterface);

// Indicate that we want PKI encryption (i.e. public-key infrastructure)
// to produce a CMS message (Cryptographic Message Syntax/PKCS7),
// that is be created with RSAES-OAEP padding, SHA256, and AES-128 for the
// bulk encryption.
crypt.CryptAlgorithm := 'pki';
crypt.Pkcs7CryptAlg := 'aes';
crypt.KeyLength := 128;
crypt.OaepHash := 'sha256';
crypt.OaepPadding := 1;

// Also, don't forget to be specific about the character encoding (byte representation) of the
// string to be encrypted.
crypt.Charset := 'utf-8';

// Now indicate that the PKCS7 output is to be returned in the base64 encoding.
crypt.EncodingMode := 'base64';

base64Pkcs7 := crypt.EncryptStringENC(sb.GetAsString());
if (crypt.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

// Show the output
Memo1.Lines.Add(base64Pkcs7);

// This base64 can be copy-and-pasted into the form at http://lapo.it/asn1js/
// to verify that all the chosen algorithms were indeed used.

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