/**
* create signatures for different call types
* @ignore
*/
public static function init()
{
self::$_createCustomerSignature = array(self::$_transparentRedirectKeys, array('customer' => Braintree_Customer::createSignature()));
self::$_updateCustomerSignature = array(self::$_transparentRedirectKeys, 'customerId', array('customer' => Braintree_Customer::updateSignature()));
self::$_transactionSignature = array(self::$_transparentRedirectKeys, array('transaction' => Braintree_Transaction::createSignature()));
self::$_createCreditCardSignature = array(self::$_transparentRedirectKeys, array('creditCard' => Braintree_CreditCard::createSignature()));
self::$_updateCreditCardSignature = array(self::$_transparentRedirectKeys, 'paymentMethodToken', array('creditCard' => Braintree_CreditCard::updateSignature()));
}