I am leaving Google and similar companies cloud services and moving to my own infrastructure for my personal data. This process is going to take a while and I am going to document it here to make it easier for others. However the obvious question is why move from free cloud services which already exist and are easy to use to paying for my own infrastructure and configuring it myself? Well partly I do not want to be the product any more which is being sold, I want to be the customer not merely a user who is being sold to advertisers. Since there is no way to pay Google to stop selling me I have to go elsewhere. I could go to someone like MyKolab which claims to care about privacy and do things properly – and people who cannot roll their own probably should think about it – but I get better guarantees from rolling my own and it should be a good learning experience.

Also Snowden. My aim is to make it such that if anyone (including state actors) want my data, then the easiest way of gaining access to it is to come and ask me nicely, we can discuss it like civilised people over tea and cake and if you make a sensible argument then you can have it. If not come back with a warrant. I am not a criminal or a terrorist and I do not expect to be treated like one with all my communications being intercepted. My data includes other people’s personally identifying information (PII) and so can only be disclosed to people who they would expect it to be given to for the purpose for which it was provided. That does not include GCHQ etc. and so I am not following the spirit of the Data Protection Act (DPA) if I make it possible for other people to obtain it without asking.

Similarly some of my friends work for Christian, environmental, aid or democracy organisations, sometimes in countries where doing so is dangerous. Information which might compromise their security is carefully never committed to computer systems (such operational security has been common in Christian circles for 2000 years) but sometimes people make mistakes, particularly when communicating internally in ‘safe’ countries like the UK. However no countries have clean records on human rights etc. and data collected by the ‘five eyes’ is shared with others (e.g. unfiltered access is given to Israel) and there are countries who are our allies in the ‘war on terror’ but which also persecute (or have elements of their security forces who persecute) minorities or groups within their country. I might in some sense be willing to trust the NSA and GCHQ etc. (because they have no reason to be interested in me) but I cannot because that means trusting 800,000 people in the US alone, some of whom will be working for bad governments.

Similarly while our present government is mostly trying to be good if frequently foolish. It is very easy for that to change. So we need to ensure that the work required to go from where we are to a police state is huge so that we have enough time to realise and do something about it. Presently the distance to cover in terms of infrastructure is far too small, being almost negligible. It is our duty as citizens to grow that gap and to keep it wide.

So I am going to try and find solutions which follow best practises of current computer security, following the principle of least privilege and using compartmentalisation to limit the damage that the compromise of any one component can cause. I am going to document this so that you can point out the holes in it so that we can learn together how to do this properly.

Maybe some of this might even help towards my PhD…

Summary: The architecture for David Cameron’s filtering plans is wrong and has a negative consequences, however there are alternative architectures which might work.

There has been much news coverage about David Cameron’s plans for opt-out filters for all internet users in the UK. With opt-in systems barely anyone will opt-in and with opt-out systems barely anyone will opt-out and so this is a proposal for almost everyone to have a filter on their internet traffic. Enabling households to easily filter out bad content from their internet traffic is useful in that there are many people who do want to do this (such as myself[1]). However the proposed architecture has a number of significant flaws and (hopefully unintended) harmful side effects.

Here I will briefly recap what those flaws and side-effects are and propose an architecture which I claim lacks these flaws and side-effects while providing the desired benefits.

1. All traffic goes through central servers which have to process it intensively. This makes bad things like analysing this traffic much easier. It also means that traffic cannot be so efficiently routed. It means that there can be no transparency about what is actually going on as no one outside the ISP can see.
2. There is no transparency or accountability. The lists of things being blocked are not available and even if they were it is hard to verify that those are the ones actually being used. If an address gets added which should not be (say that of a political party or an organisation which someone does not like) then there is no way of knowing that it has been or of removing it from the list. Making such lists available even for illegal content (such as the IWF’s lists) does not make that content any more available but it does make it easier to detect and block it (for example TOR exit nodes could block it). In particular it means having found some bad content it is easier to work out if that content needs to be added to the list or if it is already on it.
3. Central records must be kept on who is and who is not using such filters, really such information is none of anyone else’s business. They should not know or be able to tell, and they do not need to.

I am not going to discuss whether porn is bad for you though I have heard convincing arguments that it is. Nor will I expect any system to prevent people who really want to access such content from doing so. I also will not use a magic ‘detect if adult’ device to prevent teenagers from changing the settings to turn filters off.

Most home internet systems consist of a number of devices connected to some sort of ISP provided hub which then connects to the ISP’s systems and then to the internet. This hub is my focus as it is provided by the ISP and so can be provisioned with the software they desire and configured by them but is also under the control of the household and provides an opportunity for some transparency. The same architecture can be used with the device itself performing the filtering, for example when using mobile phones on 3G or inside web browsers when using TLS.

So how would such a system work? Well these hubs are basically just a very small Linux machine, like a Raspberry Pi and it is already handling the networking for the devices in the house, probably running a NAT[0] and doing DHCP, it should probably also be running a DNS server and using DNSSEC. It already has a little web server to display its management pages and so could trivially display web pages saying “this content blocked for you because of $reason, if this is wrong do $thing”. Then when it makes DNS requests for domains to the ISP’s servers then they can reply with additional information about whether this domain is known to have bad content and where to find additional information on that which the hub can then look up and use to as input to apply local policy.
Then the household can configure to hub that applies the policy they want and it can be shipped with a sensible default and no one knows what policy they chose unless they snoop their traffic (which should require a warrant).
Now there might want to be a couple of extra tweaks in here, for example there is some content which people really do not want to see but find very difficult not to seek out, for example I have friends who have struggled for a long time to recover from a pornography addiction. Hence providing the functionality whereby filter settings can be made read only such that a user can choose to make ‘impossible’ to turn off can be useful as in a stronger moment they can make a decision that prevents them being able to do something they do not want to in a weaker moment. Obviously any censorship system can be circumvented by a sufficiently determined person but self blocking things is an effective strategy to help people break addictions, whether to facebook in the run up to exams or to more addictive websites.

So would such a system actually work? I think that it is technically feasible and would achieve the purposes it is intended to and not have the same problems that the current proposed architecture has. However it might not work with currently deployed hardware as that might not have quite enough processing power (though not by much). However an open, well specified system would allow incremental roll out and independent implementation and verification. Additionally it does not provide the services for which David Cameron’s system is actually being built which is to make it easier to snoop on all internet users web traffic. This is just the Digital Economy bill all over again but with ‘think of the children’ rather than ‘think of the terrorists’ as its sales pitch. There is little point blocking access to illegal content as that can always be circumvented, much better to take the content down[2] and lock up the people who produced it, failing that, detect it as the traffic leaves the ISP’s network towards bad places and send round a police van to lock up the people accessing it. Then everything has to go through the proper legal process in plain sight.

[0]: in the case of Virgin Media’s ‘Super Hub’ doing so incredibly badly such that everything needs tunnelling out to a sane network.
[1]: Though currently I do not beyond using Google’s strict safe search because there is no easy mechanism for doing so, the only source of objectionable content that actually ends up on web pages I see is adverts, on which more later.
[2]: If this is difficult then make it easier, it is far too hard to take down criminal website such as phishing scams at the moment and improvements in international cooperation on this would be of great benefit.

Mass surveillance of the citizens of a country allows intelligence services to use ‘big data’ techniques to find suspicious things which they would not otherwise have found. They can analyse the graph structure of communications to look for suspicious patterns or suspicious keywords. However as a long term strategy it is fundamentally flawed. The problem is the effect of surveillance on those being watched. Being watched means not being trusted, being outside and other, separate from those who know best and under suspicion. It makes you foreign, alien and apart, it causes fear and apprehension, it reduces integration. It makes communities which feel that they are being picked on, distressed and splits them apart from those around them. This causes a feeling of oppression and unfairness, of injustice. This results in anger, which grows in the darkness and leads to death.

That is not the way to deal with ‘terrorism’. Come, let us build our lives together as one community, not set apart and divided. Let us come together and talk of how we can build a better world for us and for our children. Inside we are all the same, it does not matter where we came from, only where we are going to and how we get there.
Come, let us put on love rather than fear, let us welcome rather than reject, let us build a country where freedom reigns and peace flows like a river through happy tree lined streets where children play.

I may be an idealist but that does not make this impossible, only really hard, and massively worth it. The place to begin is as always in my own heart for I am not yet ready to live in the country I want us to be. There is a long way to go, and so my friends: let us begin.

I am reading “Systematic detection of capability leaks in stock Android smartphones” for the CL’s Mobile Security reading group.

I read “all the tested HTC phones export the RECORD AUDIO permission, which allows any untrusted app to specify which file to write recorded audio to without asking for the RECORD AUDIO permission.” and then went back and looked again at Table 3 and saw the other permissions that stock HTC android images export to all other applications: these include access location and camera permissions. The authors report that HTC was rather slow at responding to their telling HTC that they had a problem. Hence stock HTC Legend, EVO 4G and Wildfire S phones are a really nice target for installing spy software because it doesn’t have to ask for any permissions at all (can pretend to be a harmless game) and yet can record where you go[0] what you say and at least if your phone is not in your pocket also what you see.

This is probably more likely to be incompetence than a deliberate conspiracy but if they were trying to be evil it would look just like this.

On the plus side Google’s Nexus range with stock images are much safer and Google is rather better at responding promptly to security issues. Since my android phone is one that Google has given our research group for doing research I am fortunately safe.

I also particularly liked HTC’s addition of the FREEZE capability which locks you out of the phone until you remove the battery, just perfect for when the attacker realises you are on to them to allow them to do the last bit of being malicious without your being able to stop them.

End of being provocative. ;-)

[0] Ok so on Wildfire S location information is implicitly rather than explicitly exported so probably harder to get hold of.