Just an experiment in producing a video :-
Not especially good because I’m too lazy to go back and even out the exposure (so the lighting doesn’t keep changing).
Feb 232014
Feb 222014
Having had a wee bit of fun at work dealing with an NTP DDoS attack, I feel it is long past time to tackle the root cause of the problem – the ISP’s who have neglected to implement ingress/egress filtering despite it being considered best practice for well over 15 years. Yes, longer than most of us have been connected to the Internet.
It is easy to point at the operators of NTP services that allow their servers to be used as attack amplifiers. And yes these insecure NTP servers should be fixed, but given the widespread deployment of NTP in everything it could take up to a decade for a fix to be universally deployed.
And what then? Before the widespread use of NTP for the amplification distributed denial of service attacks, DNS was commonly used. And after NTP is cleaned up? Or even before? There are other services which can be exploited in the same way.
But the way that amplification attacks are carried out involves two “vulnerabilities”. In addition to the vulnerable service, the attacker forges the packets they send to the vulnerable service so that the replies go back to the victim. Essentially they trick the Internet into thinking that the victim has asked a question – millions of times.
Forging the source address contained within packets is relatively easy to do, and it has been known about for a very long time and the counter-measure has also been known for nearly as long. To put it simply, all the ISP has to do is to not allow packets to exit their network(s) which contain a source address that does not belong to them. Yet many ISPs – the so-called “bad” ISPs – do not implement this essential bit of basic security. The excuse that implementing such filters would be impossible with their current routers simply doesn’t wash – routers that will do this easily have been on the market for many years.
It is laziness pure and simple.
These bad ISPs need to be discovered, named, and shamed.
Feb 102014
So I’ve heard about this strange Bitcoin stuff for ages, but never found the time to look into it, until now. It cropped up at work, s I thought I should get acquainted. And this blog posting is an expression of my level of understanding, so it could well be wrong in places.
Certainly don’t take any of this as financial advice!
Bitcoin is a digital cash currency, but what does that mean?
Well the “cash” bit is understandable; it is normally expressed as a ‘peer-to-peer’ currency but essentially I hand over to you a certain number of bitcoins in exchange some agreed goods or services. Just the same as if I paid you in an ordinary currency in the form of cash.
It is a bit more complex than that as transactions have to be computationally confirmed. Or to put it another way, once you transfer the bitcoins, the transfer has to be independently verified which takes some time. The average seems to be about 8 minutes. So not quite the same as cash then; on the other hand it should be as anonymous as cash – perhaps even more so.
The “currency” bit is a tad more controversial. There’s more than a few governments that declare that bitcoins aren’t a currency but behaves more like a commodity (like gold). Of course they may be speaking with a forked tongue, or simply warning of the dangers of using bitcoins. Fundamentally a currency is a medium of exchange – so if you can find something to buy with your bitcoins, or you are prepared to sell goods or services for bitcoins, it is a currency for you.
Lastly the “digital” bit is where it can get a bit complex, so I won’t be trying. To put it very briefly, a bitcoin is a long string of digits that has been “discovered” (or more accurately mined) according to some complex calculation and then independently verified. It also includes details of all previous transactions that have occurred. The obvious question here is how is it that bitcoins cannot be forged?
There is no answer to that question without getting involved in the details of how bitcoins work computationally, but it is commonly held to be impossible without access to enough computational power to overwhelm the combined computational power of the bitcoin miners.
The Bitcoin “Bubble”?
In conventional economics a bubble is essentially some activity that becomes massively over valued and eventually loses it’s value. Examples include the South Sea Bubble, and the dot-com bubble. There are those who claim that bitcoin shares characteristics with famous historical bubbles, which is a very easy thing to say.
After all, no bubble is a bubble until it has been popped; at least in economics.
The trouble is that bitcoins are essentially worth what people agree they are worth. If everyone turned around tomorrow and agreed that they were worthless, you wouldn’t be able to spend them.
Which makes them the same as practically all modern currencies – the pound, the dollar, the euro. They are all backed not by silver or gold, but people’s confidence. Bitcoins are subject to much larger fluctuations than ordinary currencies which is at least partially a result of the small size of the bitcoins marketplace and the effect of external events such as China banning bitcoins.
The Wallet
To make use of bitcoins, you need a wallet to put them into. This is essentially an application that processes bitcoin transactions and keeps a record of how many bitcoins there are in the wallet. Full-blown wallets (such as one of the earliest – Bitcoin-QT) keep a full record of the bitcoin transactions to fully verify bitcoins; mobile wallets are less capable. Whilst there are still protections in mobile wallets, you may wish to be less trusting with mobile wallets until you know more about this than I do!
Once you have a wallet fully set up – which can take several days due to the large number of transactions it needs to download – you can start using it. Of course initially it will be empty, so you will be unable to buy anything, but you will be able to set up addresses for people to send you bitcoins which will look like 16hQid2ddoCwHDWN9NdSnARAfdXc2Shnoa.
Yes that’s a real address – it’s my “donation” address – and you are more than welcome to send me a coin or two. Or more realistically a tiny fraction of a coin.
Once you have something in your wallet, you can send bitcoins to addresses like the one above … or perhaps another address in return for something useful!
Mining Bitcoins
Previous sections have indicated that there is something called “mining” and that a great deal of computational power is behind the workings of the bitcoin network. Numerous volunteers contrib computer power – almost always using special hardware to do so – in the hope of making money.
Can you make money? Yes, but probably not enough to pay for the increased electricity bill and almost certainly not enough to pay back the initial hardware investment. People who got into mining earlier may have made a bit of money – when you could effectively mine with ordinary computer power, but unless you are prepared to invest many thousands of pounds on a regular basis it is unlikely that you will see anything like a reasonable return.
And this is probably bitcoin’s biggest weakness. The bitcoin network needs miners to validate all of the transactions that go on, and in the future, there may be a lack of volunteers if the return is not reasonable.
But of course I might be discouraging you as I’m mining a bit myself – and the more miners there are, the fewer bitcoins there are for me 🙂
Feb 062014
Recently a Creationist (Ken Ham) debated with a sensible person (Bill Nye) about the merits of Creationism. The full debate can be found online :-
However it can all be summed up by a response to a simple question: “What would make you change your mind?” :-
Bill: “Evidence”
Ken: “Nothing”
So what is this about St Augustine? It turns out that Christians have known they’ll look stupid if they get too literal about the story of creation, for a very long time. St Augustine had this to say about the likes of Ken :-
“Usually, even a non-Christian knows something about the earth, the heavens, and the other elements of this world, about the motion and orbit of the stars and even their size and relative positions, about the predictable eclipses of the sun and moon, the cycles of the years and the seasons, about the kinds of animals, shrubs, stones, and so forth, and this knowledge he holds to as being certain from reason and experience.
Now, it is a disgraceful and dangerous thing for an infidel to hear a Christian, presumably giving the meaning of Holy Scripture, talking nonsense on these topics; and we should take all means to prevent such an embarrassing situation, in which people show up vast ignorance in a Christian and laugh it to scorn. The shame is not so much that an ignorant individual is derided, but that people outside the household of faith think our sacred writers held such opinions, and, to the great loss of those for whose salvation we toil, the writers of our Scripture are criticized and rejected as unlearned men.”
St Augustine of Hippo, from “The Literal Meaning of Genesis”, appx 400 C.E.
So I guess St Augustine is busy rolling his eyes and cringing at the sight of christians like Ken.
Feb 062014
The train line at Dawlish has collapsed after the recent storms (early February 2014) – details here.
Having travelled that part of the railway several times, I can say that the train line just there was always vulnerable and this sort of damage was pretty inevitable. Of course it needs to be repaired whatever happens.
However in the long run, it is time to think of moving the train line somewhere further inland. Fantastically expensive of course, but quite possibly cheaper than doing a patch up every time a storm washes away the line over the next 100 years.