You're missing something, but I'm not sure what... Addresses are always public knowledge, along with all transactions between them. Who owns the address, on the

You're missing something, but I'm not sure what... Addresses are always public knowledge, along with all transactions between them. Who owns the address, on the other hand, is usually not advertised: but in this case Instawallet is claiming and endorsing their address to allow for instant payments on your behalf. I can't tell how this diminishes security, assuming the normal practice of using one-time receiving addresses is still used. EDIT: And assuming you are comfortable having a middleman like Instawallet involved.