src/Http/Middleware/Certificate.php
private function getDecodedSignature(IlluminateRequest $request)
    {
        $signature = $request->header(self::SIGNATURE_HEADER);
        $base64DecodedSignature = base64_decode($signature);

        return $base64DecodedSignature;
    }
private function getDecodedSignature(IlluminateRequest $request)
    {
        $signature = $request->header(self::SIGNATURE_HEADER);
        $base64DecodedSignature = base64_decode($signature);

        return $base64DecodedSignature;
    }
@param IlluminateRequest $request

@return string