A BIP32 hierarchical deterministic wallet does not provide any extra security. How it works is basically a special private key that acts as a seed for an infinite series of addresses. So if you send bitcoin to any one of the addresses, you will receive it. This is compared to a normal private key setup, where you have one for each address.
The downside of this is that if someone knows your extended public key (xPub), they can generate a list of all the addresses you own and thus compromise your privacy.
Is there any form of preventing that from happening? Is there any way someone can see your xPub?