Sign a JWS with an HMAC Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetMacKey, which sets the symmetric MAC key for a signature. The key bytes are supplied in a named encoding such as hex or base64.

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.Jws,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  jws: TJws;
  header: TJsonObject;
  bIncludeBom: Boolean;
  base64Key: string;
  jwsCompact: string;

begin
  success := False;

  jws := TJws.Create;

  //  Protected header specifying HMAC-SHA256.
  header := TJsonObject.Create;
  header.UpdateString('alg','HS256');
  success := jws.SetProtectedHeader(0,header);
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;

  bIncludeBom := False;
  success := jws.SetPayload('This is the content to sign.','utf-8',bIncludeBom);
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;

  //  Set the symmetric MAC key for signature 0.  The key bytes are provided in the named encoding (here
  //  base64).  In production, obtain the key from a secure source rather than hard-coding it.
  base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
  success := jws.SetMacKey(0,base64Key,'base64');
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;

  jwsCompact := jws.CreateJws();
  if (jws.LastMethodSuccess = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;
  WriteLn(jwsCompact);


  jws.Free;
  header.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.