1.There were 6 stations.The headquarters in Boulder was one of five “immobile” stations, all of which were participating in the ceremony from different cities across the planet. One mobile station was doing its part while making a mad dash across British Columbia. The generation of the keys was decentralized such that each station would only be responsible for creating a fragment of the bad key. For the ceremony, a cryptographic algorithm was custom designed that created a full version of the zk-SNARK parameters while keeping the pieces of the bad key segregated, a process that took two days of relaying data back and forth among the six stations.
2.The benefit of dividing up the work in this way is that no one participant can compromise the ceremony. Each fragment of the bad key is worthless unless it is combined with all the others. It cannot even be brought into existence unless all members of the ceremony collude or an attacker successfully compromises all six of the participating stations.
3.By keeping the details of the ceremony software secret, the Zcash team limited their security audit to just a handful of people inside the company, but they may also have made it more difficult for an attacker to make the kinds of preparations that would be necessary to mount a successful side channel attack.
4.The idea behind side channel attacks is that you don’t have to have direct access to a computer’s data in order to spy on it. Often, you can piece together some idea of what a computer is doing by examining what’s going on with the physical components. What frequencies are humming across the metal capacitors in a laptop? How much power is it pulling from the wall? How is the voltage fluctuating? The patterns in these signals can leak information about a software program’s operation, which, when you’re running a program that you want to keep secret, can be a problem.emphasized text
5.I dont know much about the security in Zcash from before. But it was a good story