Pascal (Lazarus/Delphi)

RSAES-OAEP Encrypt String with AES-128 Content Encryption and SHA256

See more Encryption Examples

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.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.StringBuilder,
  Chilkat.Cert,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  sb: TStringBuilder;
  i: Integer;
  cert: TCert;
  crypt: TCrypt2;
  base64Pkcs7: string;

begin
  success := False;

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

  //  First build a string to be encrypted
  sb := TStringBuilder.Create;
  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;

  WriteLn(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 := TCert.Create;
  success := cert.LoadFromFile('qa_data/rsaes-oaep/cert.pem');
  if (success <> True) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  crypt := TCrypt2.Create;

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

  //  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 := True;

  //  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 <> True) then
    begin
      WriteLn(crypt.LastErrorText);
      Exit;
    end;

  //  Show the output
  WriteLn(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.

  WriteLn('OK.');


  sb.Free;
  cert.Free;
  crypt.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.