public function getKeyPair()
    {
    	if (!isset($this->keyPair)) {
	    	$keyProviderCollection = KeyProviderCollector::getInstance();
	    	$keyProvider = $keyProviderCollection->getProvider($this->providerId);
	    	if (!$keyProvider) {
	    		throw new InaccessibleKeyPairException("Key pair provider ({$this->providerId}) has not been loaded in this instance");
	    	}
	    	$this->keyPair = $keyProvider->get($this->keyPairId);
	    }
	    return $this->keyPair;
    }