Can any of the workplace administrators have access over the workplace network to my local files? I’m using windows 7. Can they make a copy of any specific file I have on my local hard drive over the network without me knowing about it? If yes, in what kind of circumstances could they do it?

## Are Thunderbolt-enabled computers without Thunderbolt ports vulnerable to Thunderspy?

Could these two attack scenarios exploit the recently publicized vulnerability?

• Using a Thunderbolt adapter like an USB-to-Thunderbolt adapter on a computer without any Thunderbolt port
• Temporarily replacing hardware (mainboard) with hardware that has Intel’s Thunderbolt port

And if one or both would work: what would be a reliable way to protect against this on such computers (Thunderbolt-enabled or Thunderbolt not disabled and hardware-replaceable)?

## Is there a computer which can simulate all computers?

I have looked for proof that a machine cannot compute itself in more than realtime (Which would allow infinite computing speed) and I came to the conclusion that it is impossible for any computer to simulate all other computers. However, I lack proof of this intuition.

So the idea is that the state of every (modern, non-quantum) computer can be represented as a finite bitstring (just every state of registers, memory cells, and hard-drive…). However, in order to predict what this computer would do given any state, you would need a longer or at least equally long (in some trivial cases this might work) bitstring. But since there is always a bigger computer (with a longer bitstring – representation) there is no computer which can compute all computers.

However, I am wondering about the following:

Let $$f$$ be a function which maps a computable function $$g$$ and a valid input $$i_g$$ of that function $$g$$, to the result of $$g$$ given $$i_g$$:

$$f(g,i_g) = g(i_g)$$

Can you proof that:

$$\exists i_f: f(f, i_f) \mbox{ does not halt, while } f(i_f) \mbox{ does.}$$

Note that $$i_f$$ is just a bitstring, and $$g$$ can be represented by a program and therefore can be a bitstring too…

## Data structures for quantum computers

In classical computers we have List,Queue,Tree etc data structures, since classical computers using 1’s & 0’s on those data structures. Then what happens when it comes to quantum computers, Do they(scientists) need to create new data structures ? Or use existing data structures with some sort of optimization ? Thanks in advance.

## Why can’t we combine thousands of computers and dynamic programming to solve chess once and for all?

It takes 3000 years for a single computer to solve chess. But if we keep adding a computer to solving the problem, wouldn’t that divide the time it takes by 1/N for each computer we add? For example if we launched maybe tens of thousands of smaller computers, maybe using a cloud platform like AWS, and had each computer work on a small sub-problem of chess, store the results in a cloud database so the other computers know what subproblems have already been solved or are being worked on, we could solve chess in less than a week.

Why wouldn’t this work? And if it could work why has no one attempted this yet?

## Is there any way to hide my using the internet (or maximize privacy) when connected via router to other computers?

I shall begin my question with the remark that I am not tech savvy at all!

The problem is the following:

A cluster of computers (laptops, desktops, etc.) A, B, C, D… are all connected to the same router. Let’s say my computer is computer A and I am a guest at big brother Bob’s home, who owns the router and computers B, C, D…

Assuming Bob has no physical access to my computer but can access the other computers, is there a way to prevent Bob from knowing what I am doing on the internet, or even better, to completely hide from Bob that I used internet at all? (short of his contacting his ISP and demanding a report or something which would take a non-trivial amount of time and assuming I don’t download anything or watch HD videos which could show up as a sudden spike of consumption)

When it comes to hiding the names of websites I visit and internet searches, according to some research it seems like Tor does a good job in hiding it completely, even if the ISP is contacted. However, can Bob determine quickly (i.e. without contacting his ISP, using some cmd dark arts) that computer A has connected to a Tor node at all without physically accessing computer A? (Let’s say it’s not in the cluster anymore when Bob does his checks)

According to further research it seems to be impossible to get the internet history of all connected devices to a router without access to the devices, but I am unsure and opinions seem to vary somewhat.

TL;DR I’m basically looking for a way to make my internet usage as inconspicuous as possible during a very specific time period when indirectly connected to other computers via a router I don’t own, is using Tor the best thing I can do in this situation to maximize privacy?

Thank you.

## Is it safe to assume that my computer’s clock will always be synced with actual time within the second or a few seconds at the worst?

Years ago, I was running a service where the moderators were able to do various actions with massive privacy implications if the accounts or contributions were less than a short period of time. I did this by checking the timestamp against the current Unix epoch, allowing for X hours/days. Normally, this worked well.

One day, the server where this was hosted on had been “knocked offline” in the data centre where I was renting it, according to the hosting company. When it came back on again, its clock had been reset to the factory default, which was many years back.

This resulted in all my moderators potentially being able to see every single account’s history and contributions in my service until I came back and noticed the wrong time (which I might not even have done!) and re-synced it. After that, I hardcoded a timestamp into the code which the current time had to be more than or else it would trigger “offline mode”, to avoid any potential disasters like this in the future. I also set up some kind of automatic timekeeping mechanism (in FreeBSD).

You’d think that by now, not only would every single computer be always auto-synced by default with tons of fallback mechanisms to never, ever be in a situation where the clock isn’t perfectly synced with “actual time”, at least down to the second, if not more accurately; it would be impossible or extremely difficult to set the clock to anything but the current actual time, even if you go out of your way to do it.

I can’t remember my Windows computer ever having been out of time for the last “many years”. However, I do important logging of events in my system running on it. Should I just assume that the OS can keep the time at all times? Or should I use some kind of time-syncing service myself? Like some free HTTPS API, where I make a lookup every minute and force the system clock to me whatever it reports? Should I just leave it be and assume that this is “taken care of”/solved?

## how to set up multiple computers full disk encryption?

I want to set up my company’s laptops in a way that all files created on these laptops can only read by these laptops. If it is copy to a usb then that file is only readable when plug that USB in a company laptop. If plug in or copy to another non-authorized laptop then it is not readable.

Earn and Young is using this technique to protect their data but I don’t know what is it called and how to set it up. Please help 🙂 thanks guy