/**
* Initialize by signing the payload with given algorithm.
*
* @param string $payload JWS Payload
* @param SignatureAlgorithm $algo Signature algorithm
* @param Header|null $header Desired header. Algorithm specific
* parameters are added automatically.
* @throws \RuntimeException If signature computation fails
* @return self
*/
public static function sign($payload, SignatureAlgorithm $algo, Header $header = null)
{
if (!isset($header)) {
$header = new Header();
}
$header = $header->withParameters(...$algo->headerParameters());
// ensure that if b64 parameter is used, it's marked critical
if ($header->hasB64Payload()) {
if (!$header->hasCritical()) {
$crit = new CriticalParameter(JWTParameter::P_B64);
} else {
$crit = $header->critical()->withParamName(JWTParameter::P_B64);
}
$header = $header->withParameters($crit);
}
$signature_input = self::_generateSignatureInput($payload, $header);
$signature = $algo->computeSignature($signature_input);
return new self($header, $payload, $signature_input, $signature);
}
/**
*
* @see \JWX\JWS\SignatureAlgorithm::headerParameters()
* @return JWTParameter[]
*/
public function headerParameters()
{
return array_merge(parent::headerParameters(), array(AlgorithmParameter::fromAlgorithm($this)));
}
