Registering algorithms

Cose\Algorithm\Manager registers each algorithm under the identifier it declares, and Cose\Algorithm\ManagerFactory registers algorithms under aliases so that a Manager can be generated from a subset of them.

use Cose\Algorithm\Manager;
use Cose\Algorithm\ManagerFactory;
use Cose\Algorithm\Signature\ECDSA\ES256;
use Cose\Algorithm\Signature\RSA\RS256;

$manager = Manager::create()->add(ES256::create(), RS256::create());

$factory = ManagerFactory::create()
    ->add('ES256', ES256::create())
    ->add('RS256', RS256::create());
$manager = $factory->generate('ES256');

A later registration for an identifier, or, on the factory, for an alias, that is already taken replaces the earlier one. When the replacement is an instance of another class, that is a misconfiguration rather than an intent: list() keeps reporting a single entry, and which verifier answers for the identifier is decided by registration order alone, which in a Symfony application means by the service container. Such a replacement therefore emits an E_USER_WARNING. Registering the same class twice stays silent, so a container that autoconfigures an algorithm more than once keeps working.

As of the next major version, a duplicate bound to a different class will throw an InvalidArgumentException, and an explicit replace() will be the way to override a registration on purpose.

Manager::withKeyRestrictionsEnforced() returns a manager whose every algorithm enforces the alg and key_ops of the key, see Key restrictions.