protected function parse_key($key)
    {
        $ekey = new enigma_key();

        foreach ($key->getUserIds() as $idx => $user) {
            $id = new enigma_userid();
            $id->name    = $user->getName();
            $id->comment = $user->getComment();
            $id->email   = $user->getEmail();
            $id->valid   = $user->isValid();
            $id->revoked = $user->isRevoked();

            $ekey->users[$idx] = $id;
        }

        $ekey->name = trim($ekey->users[0]->name . ' <' . $ekey->users[0]->email . '>');

        // keep reference to Crypt_GPG's key for performance reasons
        $ekey->reference = $key;

        foreach ($key->getSubKeys() as $idx => $subkey) {
            $skey = new enigma_subkey();
            $skey->id          = $subkey->getId();
            $skey->revoked     = $subkey->isRevoked();
            $skey->created     = $subkey->getCreationDate();
            $skey->expires     = $subkey->getExpirationDate();
            $skey->fingerprint = $subkey->getFingerprint();
            $skey->has_private = $subkey->hasPrivate();
            $skey->algorithm   = $subkey->getAlgorithm();
            $skey->length      = $subkey->getLength();
            $skey->usage       = $subkey->usage();

            $ekey->subkeys[$idx] = $skey;
        };

        $ekey->id = $ekey->subkeys[0]->id;

        return $ekey;
    }