Quote from: jimrandomh on December 30, 2011, 08:30:22 PM

The reason for connecting to many peers is for security. If you connect to only a few peers, or you design your peer-finding system poorly, an attacker might arrange things so that all of your connections were to computers that he controlled. Then he'd be able to hide published blocks from you, and to send blocks and transactions to you that don't reach the rest of the network. This would allow him to mount something sort of like a 51% attack, but with much less computing power.

In other words, the peer-finding algorithm is security-critical, so you shouldn't mess with it unless you know exactly what you're doing. The transaction and block relaying algorithms are, too, by the way; if a large fraction of the network stopped relaying because they wanted to be lightweight, then 125 connections might not be enough to stay safe anymore.

an attacker CAN NOT create block, just because you are outside the network, he still needs a high amount of computing power, to create a block every 10 min, or even 1 at all. and without any block, there will be no confirmations. thrust an attacker CAN NOT perfrom a double spend attack on you.