Encoding for sending email gmail apex

encode.apex

String  encodedStr =  'TUlNRS1WZXJzaW9uOiAxLjANClJlY2VpdmVkOiBieSAxMC4yOC45OS4xOTYgd2l0aCBIVFRQOyBGcmksIDE4IFNlcCAyMDE1IDEzOjIzOjAxIC0wNzAwIChQRFQpDQpEYXRlOiBGcmksIDE4IFNlcCAyMDE1IDIyOjIzOjAxICswMjAwDQpEZWxpdmVyZWQtVG86IGVtdGhvbGluQGdtYWlsLmNvbQ0KTWVzc2FnZS1JRDogPENBRHNaTFJ5eGk2UGt0MHZnUS1iZHd1N2FNLWNHRmZKcEwrRHYyb3ZKOGp4SGN4VWhfQUBtYWlsLmdtYWlsLmNvbT4NClN1YmplY3Q6IFdoYXQgZGENCkZyb206IEVtaWwgVGhvbGluIDxlbXRob2xpbkBnbWFpbC5jb20-DQpUbzogRW1pbCBUaG9saW4gPGVtdGhvbGluQGdtYWlsLmNvbT4NCkNvbnRlbnQtVHlwZTogbXVsdGlwYXJ0L2FsdGVybmF0aXZlOyBib3VuZGFyeT0wMDFhMTE0NjhmMTY1YzUwNDUwNTIwMGI0YzYxDQoNCi0tMDAxYTExNDY4ZjE2NWM1MDQ1MDUyMDBiNGM2MQ0KQ29udGVudC1UeXBlOiB0ZXh0L3BsYWluOyBjaGFyc2V0PVVURi04DQoNCmhlY2s_IE5vIGF0dGFjaG1lbnQ_DQoNCi0tMDAxYTExNDY4ZjE2NWM1MDQ1MDUyMDBiNGM2MQ0KQ29udGVudC1UeXBlOiB0ZXh0L2h0bWw7IGNoYXJzZXQ9VVRGLTgNCg0KPGRpdiBkaXI9Imx0ciI-aGVjaz8gTm8gYXR0YWNobWVudD88L2Rpdj4NCg0KLS0wMDFhMTE0NjhmMTY1YzUwNDUwNTIwMGI0YzYxLS0=';
encodedStr = encodedStr.replaceAll('-', '+').replaceAll('_', '/');
Blob decodedBlob = EncodingUtil.base64Decode(encodedStr);
String decodedStr = decodedBlob.toString();
System.debug(decodedStr);

String newEmail = decodedStr.replaceAll('[email protected]','[email protected]');
Blob sendBlob = Blob.valueof(newEmail);
String encodedNewString = EncodingUtil.base64Encode(sendBlob);
encodedNewString = encodedNewString.replaceAll('[+]','-').replaceAll('[\\/]','_');
System.debug('=====');
System.debug(encodedNewString);
System.debug('=====');