if err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}

	n, err = base64DecodeBytes(token[i+1:j], buf)
	if err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}

	if err = claims.UnmarshalJSON(buf[:n]); err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}