By securely I mean without the risk of them committing cybercrimes or contacting victims or other people to commit more crimes ? I've read that even with firewalls a way around it could be found, especially if the allow list is large enough.

I was reading about how there is a restricted Internet access in Denmark and Belgium for prisoners.

Denmark seemed to have shut it down temporarily due to security issues.

  • 2
    In-cell devices are a thing in a considerable number of prisons in the UK. They operate on a white-list site/walled-garden principle - Only certain sites can be accessed, access is a privilege, prisons who need to be prevented from contacting victims or intimidating witnesses are excluded from access entirely, or have a very small list of utilitarian sites that they can access, such as food ordering or email to pre-approved contacts. insidetime.org/7-more-prisons-to-get-in-cell-tech
    – Richard
    Commented May 6, 2023 at 10:22

3 Answers 3


There is at least one specific project that I know of, Kiwix, with a blog post about its use in French prisons.

The idea is to download an admissible website in its entirety (into a static ZIM archive), then make it available via a storage medium to offline computers.

The kiwix project offers a quite large set of maintained archives in their library including

  • Wikipedia in many languages
  • TED talks
  • Books that are in the public domain
  • Stackexchange sites

So, it's not what most users have, interactivity, but it still allows an otherwise offline population access to a part of the vast knowledge available in the internet.

  • Yep. I'll add an immutable Linux component such as AshOS to the mix. Many other layers of security need to be thought out, though.
    – Deepak D
    Commented May 5, 2023 at 8:41
  • 3
    One might argue that that is not "providing the Internet". And as an aside, I can imagine so many ways to use URLs as a means of outgoing communication: "If you want us to sell drugs, visit this URL. If you want us to sell weapons, visit this other URL" and both URLs show images of cats and dogs, but the visit is logged. And even searches, if permitted, could pass data.
    – schroeder
    Commented May 5, 2023 at 13:23
  • 10
    @schroeder What do you mean, how would anyone outside see which "urls" are visited if they seemingly just make offline copies?
    – MaxD
    Commented May 5, 2023 at 17:45
  • 5
    @MaxD: It depends on how the offline copying is triggered. You are not going to copy the entire WWW, so you need to pick and choose which sites to copy. If you just take a static list of the top (say) 100 websites and spider/copy them, then fine, it probably won't cause any issues (but it won't be comprehensive). But if you make a copy on-demand every time the prisoner tries to navigate to a URL you've never seen before, then the prisoner can indirectly cause an HTTP request to be sent. There are also various middle grounds you could adopt, with varying levels of risk.
    – Kevin
    Commented May 5, 2023 at 18:52
  • 6
    @schroeder If they were doing automated on-demand copying of requested URLs from the public internet into the offline archive as prisoners are requesting them, that's not an offline archive, it's a needlessly complicated web proxy. What the answer describes sounds more like an offline network that has been built with a copies of a bunch of websites that were pre-selected by the administrators. I would assume it does not allow free choice of what sites to visit, and it sounds like that is the entire point.
    – Ben
    Commented May 8, 2023 at 2:24

Every kind of communication from inside the prison to outside the prison might cause the problems you describe, no matter if snail mail, phone calls or internet. How large the problem is depends on how restrictive the communication is and how extensively it is monitored and of course the individual motivation of prisoners to misuse this communication path.

Like everything in security it is a trade-off, this time between allowing prisoners a better integration into the current society where internet is an essential part on one side and the risks that such communication might be misused on the other side.

While it is technically possible to restrict access to only a few sites, this at the same time might make internet access practically unusable and thus does not provide the intended effects why internet was allowed in the first place.


Prisoners could be given access to only a white-list of sites, sites regulators have examined closely for means of communication. If no sites that allow user generated content are included in the white-list, there's little risk of illicit communication. Some commenters have brought up ways that merely making page requests can be used to encode messages, but this requires the site to be in on it. I believe the white-list solves this risk; I don't believe Encyclopedia Britannica would aide a witness intimidation plot. It is possible, in theory, for a tech-savvy prisoner to discover an exploit on a white-listed site, but then again it's possible for a savvy prisoner to tunnel out of his cell Shawshank Redemption style. I don't think perfect security is possible or expected.

  • 2
    It's a good defense, but only one layer. Whitelisted websites can suddenly add community features (an unfortunately popular move), and encoded messages don't require participation from the website; showing a view count is enough, for example.
    – BoppreH
    Commented May 5, 2023 at 16:30
  • 1
    The whitelist would also need to address things like ad networks, 3rd party JS libraries, CDNs, etc., any of which could also be subject to various vulnerabilities from supply chain injection to DNS hijacking, depending on the value of the communication. It's an interesting idea, though.
    – minnmass
    Commented May 5, 2023 at 17:20
  • 1
    @minnmass sure, so there would be severe restrictions on those, possibly using a local proxy that doesn't allow access to outside copies of the files served by them at all, only through a filtered and semi-regularly updated local copy. Same way severely restrictive corporate networks handle such things.
    – jwenting
    Commented May 8, 2023 at 6:11

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .