src/Request.php
private function signature(array $payload, $method, $uri, $secret)
    {
        $payload = urldecode(http_build_query($payload));

        $payload = implode("\n", [$method, $uri, $payload]);

        return hash_hmac('sha256', $payload, $secret);
    }
private function signature(array $payload, $method, $uri, $secret)
    {
        $payload = urldecode(http_build_query($payload));

        $payload = implode("\n", [$method, $uri, $payload]);

        return hash_hmac('sha256', $payload, $secret);
    }
private function signature ( array $ payload , $ method , $ uri , $ secret ) { $ payload = urldecode ( http_build_query ( $ payload ) ) ; $ payload = implode ( "\n" , [ $ method , $ uri , $ payload ] ) ; return hash_hmac ( 'sha256' , $ payload , $ secret ) ; }
Create the signature

@param array $payload
@param string $method
@param string $uri
@param string $secret
@return string
Create the signature