Gateway/Config/Config.php
public function getPrivateSharedKey() {
        return (string) $this->encryptor->decrypt($this->getValue(
            self::KEY_PRIVATE_SHARED_KEY,
            $this->storeManager->getStore()
        ));
    }
public function getPrivateSharedKey() {
        return (string) $this->encryptor->decrypt($this->getValue(
            self::KEY_PRIVATE_SHARED_KEY,
            $this->storeManager->getStore()
        ));
    }
public function getPrivateSharedKey ( ) { return ( string ) $ this -> encryptor -> decrypt ( $ this -> getValue ( self :: KEY_PRIVATE_SHARED_KEY , $ this -> storeManager -> getStore ( ) ) ) ; }
Returns the private shared key used for callback function.

@return string
Returns the private shared key used for callback function .