Digital imprimatur

É do final do ano passado, mas só vi agora. De qq modo, vale dar uma lida neste artigo: Digital Imprimatur. O texto feito por um dos fundadores da Autocad e ex-líder recentemente falecido projeto Speak Freely, John Walker (veja nota), discute o uso de certificados digitais no micropagamento, DRM, propriedade intelectual, etc. Além disso, vale destacar um alerta para os libertários da internet sobre o crescente número de conexões Network Address Translation (NAT).

De acordo com Walker, ao não dar um IP "de verdade" para o usuário final, as grandes empresas estariam fornecendo conexões de segunda classe, pois o NAT diminui a capacidade de servir informações, perpetuando os clientes na posição limitada de consumidor de serviços e informações.

But NAT, like dynamic IP addresses, once again divides those on the Internet into two classes. While the dynamic IP user's address changed with every online session, at least for the duration of that session it remained constant and was accessible from the outside world, just like a permanently connected host. Once users exchanged their current IP addresses through one of the server-based schemes, they were free to then open any kind of connection between their machines supported by Internet protocols. The NAT user, however, finds himself at a further level of remove from the "raw" Internet.

Recall that the NAT box assigns a port for each connection from a machine on the internal subnet to an external site only when the local machine initiates a connection. Otherwise machines on the internal subnet are completely inaccessible from the Internet at large--the other side of the NAT box. They do not have an externally visible IP address at all, fixed or dynamic, and there is no way an external site can communicate with them unless the local machine has first initiated the connection. A machine behind a NAT box cannot act as a server, because there is no address which remote sites may use to open connections to it. Two users behind NAT boxes cannot even create a peer to peer connection between themselves, since neither has an address which will accept connections initiated from outside. If they wish to communicate, they must both connect to a server (not behind a NAT box) which will then relay the data between them. This creates a point of control far more powerful than a "meeting place" server for dynamic IP address users. A server which forwards traffic between NAT users must have sufficient bandwidth to accommodate not only lookup requests but all the data sent between its users, and has the ability to monitor and potentially intercept all the traffic it relays.