Set a Per-Recipient JWE Header

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetRecipientHeader, which sets the per-recipient unprotected header for a recipient index.

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.Jwe,
  Chilkat.StringBuilder,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  jwe: TJwe;
  header: TJsonObject;
  base64Key: string;
  recipHeader: TJsonObject;
  sbContent: TStringBuilder;
  sbJwe: TStringBuilder;

begin
  success := False;

  jwe := TJwe.Create;

  //  Protected header: AES key-wrap with AES-256-GCM content encryption.
  header := TJsonObject.Create;
  header.UpdateString('alg','A256KW');
  header.UpdateString('enc','A256GCM');
  success := jwe.SetProtectedHeader(header);
  if (success = False) then
    begin
      WriteLn(jwe.LastErrorText);
      Exit;
    end;

  //  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
  //  secure source rather than hard-coding it.
  base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
  success := jwe.SetWrappingKey(0,base64Key,'base64');
  if (success = False) then
    begin
      WriteLn(jwe.LastErrorText);
      Exit;
    end;

  //  Set the per-recipient unprotected header for recipient 0, for example a key id used to identify
  //  which key a recipient should use.
  recipHeader := TJsonObject.Create;
  recipHeader.UpdateString('kid','recipient-key-1');
  success := jwe.SetRecipientHeader(0,recipHeader);
  if (success = False) then
    begin
      WriteLn(jwe.LastErrorText);
      Exit;
    end;

  sbContent := TStringBuilder.Create;
  sbContent.Append('This is the secret content.');
  sbJwe := TStringBuilder.Create;
  success := jwe.EncryptSb(sbContent,'utf-8',sbJwe);
  if (success = False) then
    begin
      WriteLn(jwe.LastErrorText);
      Exit;
    end;
  WriteLn(sbJwe.GetAsString());


  jwe.Free;
  header.Free;
  recipHeader.Free;
  sbContent.Free;
  sbJwe.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.