src/TwitterOAuth.php
private function encodeAppAuthorization(Consumer $consumer)
    {
        $key = rawurlencode($consumer->key);
        $secret = rawurlencode($consumer->secret);
        return base64_encode($key . ':' . $secret);
    }
private function encodeAppAuthorization(Consumer $consumer)
    {
        $key = rawurlencode($consumer->key);
        $secret = rawurlencode($consumer->secret);
        return base64_encode($key . ':' . $secret);
    }
Encode application authorization header with base64.

@param Consumer $consumer

@return string