Schneier on Security

Clive Robinson • June 18, 2016 7:55 AM

@ Wael,

Is that realistic?

It depends not so much on the strength of the ciphers but the quantity of messages and the timelyness of delivery and type of transmission.

If we start with a couple of basic assumptions. The first that a “split message” is secure unless the enemy gets access to all thr parts. The second that if the enemy gets access to any part they can not hide the fact they have done so.

Then it’s possible to use the same transmission channel to send all parts of a message provided there is a sufficient time gap between them.

So if I come up with a foolproof tamper evident envelope system for Alice and Bob to use, Alice can split a message and put one part in an envelope and give it to a courier to hand carry to Bob. On arival Bob puts a suitable acknowledgment of some type into another envelope and sends it back with the courier to Alice. When Alice gets the acknowledgment back she can then give the courier the next part of the message. If the courier gets grabbed then he has nothing to give up to the enemy other than the current part or acknowledgement sealed in their envelopes and the knowledge of how many envelopes he has personaly carried. To be able to get any message the enemy need to be able to turn the courier and they must have a way to read the message without triping the tamper evident envelopes. If a courier is lost or an envelope tampered with then the other part of the message is not sent. However other messages can still be sent either by a new courier, or the same one.

This system has been used with diplomatic couriers long prior to the realisation of the OTP and is the basis of Quantum Key Delivery systems used to transmit an OTP between two parties.

The two main problems with the system are. Firstly the round trip delay and secondly how to deal with lost message parts / couriers.

The strength of the system ultimately rests on the secure envelopes and proper protocol behaviour by Alice and Bob, part of which is the spliting function.

At one point in time the splitting function would have been something like a set of numbered grills, one for each message part. These would be burned and replaced if a message part was lost.

As usual such systems become insecure over time due to technology changes and with impatience of the users at the time and cost of operating the system.

Such changes as moving from a single end to end courier to a more general shared courier service, which was faster and less expensive. But unfortunatly where it was possible for an enemy to examine the envelopes and develop methods to circumvent them, thus by examination work out the grils in use etc. See the history of the Geheime Kabinettskanzlei (secret chancellery) in Vienna where it was turned into an industrial process, and amongst others provided gainful employment to the artist Joseph Mahler.

Clive Robinson • June 18, 2016 9:25 AM

@ Putin Outs Clinton, All,

Russian President Goes After Hillary By Releasing 20,000(!) Of Her ‘Private’Emails

Whilst the political and corruption side is quite yawn worthy, the security story behind it is perhaps a little more interesting.

The 20,000ft overview story so far is HRC had a private Email server that got hacked by an individual. The fact that it got hacked is not security news, I suspect by far the majority of Email server software is relatively easily hackable, and for those that are not the OS or other apps on the server hardware or backup taking/keeping hardware are. Thus getting access to the actual Email records is not going to be that hard as history has repeatedly shown [1][2].

This is why network diodes, guards, pumps and sluices have been developed and used to provide “gapping” and “unidirectional traffic” on clasified networks for some time now with full air/energy gaps for the more secure requirments.

The interesting bit is that the hacker appears to have been “caught in the act” in some way by Russia and that is how they have got copies of the Emails.

There are various scenarios for this but the one that is of interest is that Russia also –perhaps unsuprisingly– opperates a “collect it all” policy and system as well. Which leaves the question as to how the traffic fell under their gaze…

So a message for all you hackers out there, “Make sure you encrypt data before exfiltration” otherwise you will not know who else has copies…[1]

[1] It’s an old mistake to make, if you are old enough to remember the Iran-Contra Affair staring Ollie North the enchanting Fawn Hall nearly thirty years ago. What got found were plaintext emails on the backups of intermediate hosts that routed them…

[2] As has been remarked in the past, ‘The more things change, the more they stay the same'[Karr 1849], and thus ‘Those who cannot remember the past are condemned to repeat it'[Santayana 1905].

Clive Robinson • June 18, 2016 6:43 PM

@ Spooky,

For some reason, the primary long-standing memory that I have of the whole Iran Contra affair was their impressive shredding operation, or Shred Parties as they were called.

Yes there were plenty of paper shreding parties, and even “dress stuffing events”. I must admit my main memory of the time was where did the lucky so-n-so get such an attractive and class act secretary from 😉

However the smoking gun was the IBM office productivity system that the NSC used. It could run on mainframes and mini computers, and could be accessed with PC’s with IBM terminal cards and software. It was this system which North and Poindexter communicated on electronicaly. Both were unaware that deleting their personal message files did not delete backups held on tape etc.

The investigating committee had been given some emails but they contained refrences to emails they had not seen this “meta data” enabled a profficient assistant to seek them out. But how he did it was not officialy said initialy, it was later revealed as from backups on intermediate machines.

You can read more in an LA Times article of 10th Aug 1987, which they have helpfully put up online,

http://articles.latimes.com/1987-08-10/business/fi-58_1_computer-files

If you want to know the contents of some of those emails have a look at,

http://nsarchive.gwu.edu/NSAEBB/NSAEBB113/

Enjoy.

Clive Robinson • June 18, 2016 7:26 PM

@ Secret Sysadmins,

Amidst the fog of BS, I think you are forgetting a key part of the story from about a year ago when it all started bubbling up. That the Secret Service was managing security for the server in question. Or was that some BS itself?

The honest answer is I don’t know the who or the what of the Clinton Email server. There are so many allegations and suppositions involved that it’s difficult to judge what may be true or not.

And “managing security for the server” can mean many different things. That is from just unknowingly guarding the building through knowingly guarding the physical hardware, to the point of actually having console access and full SysAdmin responsibilities…

It’s all a mess and “kicking up the riverbed” just clouds the issues further.

Clive Robinson • June 19, 2016 2:55 PM

@ herman,

As an ex army officer, I have to agree that a rifle in the hands of an untrained person is not a good idea, but if someone in that hall was able to shoot back accurately, things could have ended much differently.

I don’t know which army you claim to have been an officer in but, in most armies the soldiers on average can not shot all that accurately.

Let’s put it this way with a rifle good to 2cm/100m most soldiers would be very lucky to get a 20cm grouping over 10 shots in favourable unstressed conditions.

Further most people do not carry rifles around with them as they tend to be heavy, inconvenient and make them a target. So if alowed they carry hand guns. When hand guns were alowed in the UK, I used to fire them both for qualifying and sport. I do not consider myself a good shot with a pistol but there were a lot worse than me. Many who could barely hit a 1m by 1.75m board onto which their target was pasted from 25m, in favourable and unstressed conditions.

Thus I find your argument about “if someone in that hall was able to shoot back accurately”, abit like saying “if somebody won the Euro Millions jackpot”, only a few people ever fall in that group and the chances are you will never meet one on the day the beat the odds.

The simple fact is that the average person would be more likely to do the shooter harm with a higher class laser pointer than they would with a hand gun, and though still legal to carry higher class laser pointers around few if any do.

Clive Robinson • June 19, 2016 6:10 PM

With regards javascript.

I generaly have it turned of on the mobile device I use to graze the internet.

As for sites –like forbs– that just will not load anything with Js turned off… I treat them the same way I do pay-walled sites. Which is, they chose to require it, I chose not to have it, as my wishes overrule their petty requirments, it’s by by site, it’s their loss not mine.

Clive Robinson • June 20, 2016 12:54 AM

@ Life by 1000 bandaids,

My initial thought was, how could a mere mortal ever hope to protect themselves in the slightest? I caused me much distress to say the least.

Whilst it can seem like you “get thrown under the bus before you can walk” with the Internet there are some quite simple things you can do to reduce your risk.

As I noted above by far the majority of attackers need an “execution environment”. If you can deny them this then it’s effectively game over, unless they can manipulate you or another user of your computer via content you actually experience to do something you should not.

But even if an attacker can get an execution environment, they still need access to other resources to do harm. This is the idea behind Sandbox and Virtual Machine technologies, which are an extention of the earlier ideas around diskless network based thin clients of the 1990’s and earlier. You can emulate much of the thin client security by using a CDROM based OS running in RAM on a computer striped of all but essential resources. This has been a security recomendation for twenty years now and is still the best way for most ordinary users to go. Sadly though Linux Magazine’s that have CDs and DVDs on the cover “ready made” to do this are becoming a thing of the past.

Outside of this, the real problem many people make, is the mistake of mixing up three activities they realy should keep seperate,

1, Private productivity activities.
2, Personal social activities.
3, Entertainment activities.

One reason for this difficulty is the root of all evil “Money”. Much of the Internet is predicated on “in band financial transactions” which blurs the edges of these activites significantly for many people.

Financial transaction security is at best a joke and in most cases nonexistant in any meaningfull way. The reason for this is that the central payments systems owners have externalised their risk to the account holding issuing banks, who in turn have externalised the risk to the account holders and merchants. So their primary interest is not in improving security for account holders or merchants because that would mean taking some or all of that externalised risk back again. There are ways you can limit the risk with some types of “virtual credit cards” or “pre pay cards” but they are very jurisdiction dependent, as are the dispute resolution options.

But the other significant reason why there is bluring or no seperation of these activities, is that humans are social creatures, who usually carry out the three activities in a place they feel secure in. Thus they do not think defensively as they would in other places.

Whilst there are technical solutions to some of the above issues that might actually become secure –think issues with SSL etc– one day, the others require legislation and education. On the issue of legislation it is clear that there is a wide disparity on what legislators think or are coerced into thinking. The US for instance significantly favours commerce over privacy, the EU much less so. The result as was seen over various IP issues imense and well financed lobbying from US interests aimed at EU legislators and as that did not have the desired effect now secret trade agrements. Where US Corporate lawyers get not only to see the secret negotiations they have major input into them, whilst elected officials and citizens have no say in the matter.

But importantly at the end of the day individuals who are adults, are deemed to be responsible for their actions and any harms they might cause. Part of being a responsible adult is learning right from wrong at a level society in general holds as a norm.

The problem with this is most humans only relate to tangible objects in a physical universe. That is nearly all their assumptions about the way things work are based on reasoning about tangible objects they can directly sense. Not however tangible objects outside of their ordinary sensing abilities or more significantly intangible information that has no physical limitations. Thus their ordinary learned abilities mislead them into making incorrect assumptions thus reasoning, which means things can and do go horribly wrong.

The solution to this as has always been the case is a mixture of education and experience. Currently few Governments require children to become educated in the practicalities of intangible information nor is there much experience that the majority of adults have that can be passed on. Whilst the former can be changed with political will, the latter will take several generations to become ubiquitous (think about the history of cars to see why).

Clive Robinson • June 20, 2016 1:29 AM

@ NTH, Figureitout, Wael,

Is there a pen-and-paper method for establishing a shared secret over insecure channels?

I suspect you are not asking the question you should be asking, which is why you got to replies that are correct but appear to conflict with each other.

If you are only talking about getting a “number” that only the two people know, then providing they know they are actually talking to each other –which is a big IF– then Wael is correct with a lot of paper and pencils and a calculator you could use the DH Protocol for secret sharing (though how much longer DH will be valid for is an open question).

But that “big IF” is a major problem because it allows for impersonation attacks, which is what Figureitout is talking about.

As can be quickly realised, if you can not authenticate the person you are talking to then you could share a secret number with the wrong person. As history shows a secret shared with the wrong person gives that person a number of opportunities to cause harm.

The unsolved and possibly unsolvable issue is the very important authentication step. If you think about it there is currently no way to tell remotely if the person is who they say they are without a “trusted” third party the two parties already share a secret with. But this only works if the third party can not be impersonated or cheated and is compleatly trustworthy.

Clive Robinson • June 21, 2016 2:34 AM

@ Dirk Praet,

Irrespective of your position on gun control, am I the only person to think that this would be an incredibly stupid idea?

It is an incredibly stupid idea.

With regards intoxication, –ignoring the legality of the chemicals injested as it’s a different isssue–, the main reason people take them is that they have a mood altering effect. Usually the effect people want in a club or similar social situation is to appear more self confident out going etc. In short “less restrained” by the social norms and rational thought.

You only have to see some of the incredibly silly behaviour people get up to like “drinking games” taking off of clothing etc to realize that having “over confidence” can lead to poor rationality. But anyone who is sober that has sat through a weekend night in a Hospital emergency department and seen people who had been “glassed” or “bottled” being wheeled in should know that a place where people are having a lack of impulse control and over self confidence due to intoxication is not a place for weapons of any kind at any time.

Also there tends to be a childish attitude to weapons in many, where people think that just holding it conveys some kind of status. Thus the more potent the weapon the more status they assume it confers. Which starts a “mine is bigger than yours” race. This sort of escalation puts increasingly more dangerous and difficult to operate weapons in less than qualified hands. It also causes a different form of escalation which is the “respect entitlement” one, where a person gets upset when they do not think that the weapon they are holding is giving them the respect they are entitled to. Thus we get stand offs that turn to trigger pulling with weapons that can pass through furniture, internal and external walls and still have sufficient energy to be lethal.

And to make a point about injested chemicals, do you realy want to have some one strung out and jittery on coffee pointing a gun at you as part of their job? I suspect not, and I certainly don’t either.

Which raises the question of if people who have injested coffee, nicotine or other legal chemicals should be alowed to carry weapons.

I know from experience that an “adrenalin rush” impairs judgment. I got lucky in that no harm came to me and I managed to get others out of danger, but it could so easily have gone the other way.

Clive Robinson • June 21, 2016 3:37 AM

@ Glomar,

I just hatched a “new” conspiracy theory chatting with a friend a few minutes ago:

You are by no means the first, and certainly will not be the last.

But why do you call it a “conspiracy theory”?

People talk of “means, motive and opportunity” when talking about crime. We certainly know the FBI had the opportunity, we know they have the means, which leaves motive… Well people also talk about criminals having an “MO”, it’s certainly been demonstrated that the FBI have considerable “previous” in setting people up as patsies for “terrorism” in what most who think about it say is “entrapment”.

If you were talking about others not a LEA in this way you would be calling them a “Dangerous Career Criminal”.

So do you want to have a rethink on using “conspiracy theory”?

Just a question as the say 😉

Clive Robinson • June 21, 2016 7:07 AM

@ Figureitout,

Just need a good reason for it or it’s a waste of time.

You actually need a couple of good reasons 😉

The first is a need for privacy, the second a need for secrecy.

Sadly the need for both is not just iminent but a requirment for many.

Currently the authorities in the US, UK, Auz and several other places encoraged by various industry lobbyists are trying to remove privacy entirely, and have more or less succeeded for communications. That is they want to get at your communications of any type for amongst other things profit at your expense.

Thus people already have a need for “secure communications” in the same way they have for four walls, doors with locks and curtains for the windows. Not because they are doing anything wrong, quite the contrary to stop others doing wrong to them by stealing from them.

That is in my home, office and other place not specifically designated as public I have considerably more than an “expectation” of privacy. It is public places where I only have an expectation of privacy.

Now there are also occasions where it is desirable and actually legaly required that I use “secrecy”. That is I am required by law to take active steps to limit the number of people that are party to information. That is it’s not just Doctors, Lawyers and the Clergy that have “a duty of confidence”, it’s those involved with finance, inventions and all manner of aspects of trade and employment etc.

Contrary to what some legislators think, they can not just gather peoples data, even though it might be in plain sight. In the same way you can not just pick up and take away physical items that are in plain sight. Even though an object might be intangible, it is still property and the owner has rights over it. This has been established over case law going back centuries.

It’s the reason “theft” has been described as “Denying the owner the rights and privileges pertaining to ownership”. At the very least you have copyright over everything you say, write and do, either as an original or derived work. For it to be otherwise due cause has to be shown and due process followed. Which put simply means it is subject to independent oversight by the judiciary.

Thus as we have in effect lost our right to privavcy in communications due to ongoing illegal activities, we have to take additional steps to ensure it. It is the same as shutting and locking your door, or transporting large quantities of money in an armoured truck.

Up till now such methods have been available if people wanted to use them, but they did not know they “had need” to use them. Now they do know they “have need” to use them the legislators are seeking to invalidate where they can such methods. Usually by faux argument preceded by considerable FUD.

A significant problem with regard to “the need” is that third parties effectivly control the end points of electronic communications. Thu methods on such equipment are subject to third party control above and beyond that of the user.

Therefor the third party due to currently known legislation can safely be assumed to be an “agent of the authorities” irrespective of any contract or agrement that might be in place.

Which means that with a legal requirment for secrecy, you have to look to methods beyond any third party influance or control.

Whilst there are methods other than pencil, paper, dice and match, their very trancparency to any kind of subversion makes them more trustworthy than other methods.

So yes whilst paper and pencil methods can be cumbersome, difficult to operate securely and difficult to transfer keying material securely, they are in effect the last line of refuge as well as the last communications end point outside of your body.

As they are in effect the “last line of defence” they are worthy not just of understanding but practical training etc, so they are in your head as and when you need them, just like the knowledge of how to change a bulb or fuse. So that if the need becomes a requirment, the methods can be called into use quickly in an emergancy when all else is failing.

To that end people often talk about “the need for OTPs” in the real world and it’s interesting to note the answers given by people. Those who tend to have quiet comfy nine to five lives behind a desk where little tends to go wrong by and large say “no need” or “problematical” due to KeyMan issues. Whilst those bouncing around in the back of beyond where things go wrong almost on an hourly basis despite good planning and preperation and have to maintain secure comms no matter what, tend to take an opposit view of “when you need them, you need them desperatly”. Experience has taught me it is better to be in the latter group thinking, no matter how comfy your life currently is “as 541t happens” you just do not know when.

Clive Robinson • June 22, 2016 2:35 AM

@ Anon10,

In the US, most jurisdictions require mandatory reporting to law enforcement from health care providers of any injury suspected of involving a firearm.

Yes and other jurisdictions as well, but you’ve missed my point.

When a gun is fired negligently or not, the bullet has to go somewhere. In the case of reporting it’s generaly not where that is the criteria but what damage it does. Thus there is a significant reporting threshold.

For instance a bullet that cuts a chunk out of somebodies boot, but not their foot as it passes into the ground is not going to get reported. Likewise one that goes whistling off through the trees etc.

So the number of negligent discharges reported as “accidents” due to ingury/death is a fraction of those that happen.

The question then is how do we extrapolate back from the number of “accidents” to the actual number of negligent discharges or shots that miss the intended target?

I could for instance take the US Armed fources figures from conflicts that very roughly indicat a 10e4-10e5 diffrence to rounds used to enemy killed… This appears very high but is confirmed by other conflicts. Further target range figures for initial training military personnel for small arms fire are only a couple of magnitudes down on that…

So the percentage of “accidets reported” of the total negligently fired is I suspect in the 0.1-1% range.

This does not appear to far off when you look at “crazy cop” reports, where cars with suspects in have hundreds of bullet holes in them. Likewise the numbers reported for terrorist attacks in open spaces.

Now irrespective of if you like or dislike my figures, it does not change the point of,

“The number of reported “accidents” are just a small fraction of the total number of those negligently discharged”.

Thus we move onto Nick P’s observation about the difference between rural and city stories.

As I pointed out, in rural areas a bullet rarely hits anything of value, even when it does (red-neck traffic sign shooting) it rarely gets reported. In the city however, it’s difficult not to hit something of value and outside of “bad areas” where insurance costs are high that damage will mostly get reported in one way or another unless the damage is to property of the gun owner or known associate and those involved want to keep it quiet for some reason.

Clive Robinson • June 23, 2016 2:17 AM

@ tyr,

Having seen a recent TV commercial for a toilet seat lighting system that detects your presence…

Hmm electricity in your very cheaply made[1] toilet seat with a bowl full of earthed water that your dangly bits might touch in hot sweaty weather. What could possibly go wrong….

[1] It would have to be cheaply made due to costs of manufacture, and advertising etc on what I suspect is going to be low volume sales[2]. So production in some sweat shop garage around the back of nowheresville Fareast selected from the darker recesses of alibaba’s trade directory (www.alibaba.com/companies).

[2] Yes I know the US has such shows as “Pimp my Ride”, but seriously how many of the ~320million US citizens are going to have the sort of “taste” that thinks (depending on colour change rate) a 70’s disco or worse 60’s “Luve shack” mood effect lighting is “hip and trendy dee’ corr” for their toilet? Hmm I wonder if the inventor tried to get funding on the US version of dragons den, now that could have been “entertainment”.

Clive Robinson • June 24, 2016 12:31 AM

@ ianf,

You might find this of interest,

In those places with most graduates the average level of support for Remain was 58% (typified by high Remain votes in Edinburgh, Oxford, and Cambridge) whereas in those with fewest graduates it was just 39%.

It’s from a piece by Professor John Curtice (Polling expert) currently on the BBC news page, but how long it will stay there I’ve no idea,

http://www.bbc.co.uk/news/live/uk-politics-36570120

It appears your “referendumb” hypothesis has validity. The “little Englanders” in their Northern issolated –virtual– “Power House” of desolation were have had their say…

Clive Robinson • July 22, 2016 4:04 AM

@ Figureitout,

With regards wear leveling, it’s an interesting question.

First off we have alternative technologies that do not require wear leveling just bad block marking. The problem is they are “not as convenient” and sometimes contain mechanical components so are considered “more fragile”[1].

But electricaly nand flash drives have little hope of lasting out the guarantee time without wear leveling, which is something people should get between their ears. Paper pencil and eraser appear to be more reliable in write cycles than some of the cheaper flash devices. In fact the flash in the microcontroler is actually likely to be more reliable than the flash in the attached memory chips of quite a few thumb drives…

So the question that arises is why do we manufacture and sell such unreliable devices?

So users should realy regard them as Write Once Read Many (WORM) ROM not reliable in any other mode of use… As for security well unless you use file level encryption of the right sort you are going to leave bread crumbs that can be got at by those with the right equipment. Again you should consider another issue which is in effect that of ‘traffic analysis’. Basicaly you have a time based history of activity on the drive showing which files have been updated, which if the crypto mode is wrong may alow a “plaintext in depth” attack… Thus flash devices are not something you should consider for securing “work in progress”

As for the cost of the devices, I can remember paying $2/MByte for them you can now get multiple GByte devices for well under $10. So with a price deflation of that level you have to ask “What the real price is?” that is what has been given up in the “race for the bottom”. Quality, Support, reliability, data security etc etc, as the old saying has it “Sometimes you get what you pay for” good or bad, hence “Buyer beware”.

As for (ab)users and support mankind in the western world is in most cases a “petulant child”, you can blaim the “Make it so” mentality which avoids responsibility of understanding what you are asking others to do.

In most western countries you are required to show minimal competence and health to be permitted to drive a vehicle. People accept this because it is easy to see the risk to others of not having these requirments. Likewise much machinery requires the user to be qualified to use. However we don’t require computer users to be tested and licenced, arguably on the cost basis computer users are considerably more dangerous than car drivers.

Thus everything appears upside down with computers compared to things we are more used to in society. If we can get things the right way up or not will depend more on money than will, and the Chinese amongst others would not be happy as it would destroy their business models as well as those such as Google, Facebook, Twitter and many others.

[1] Whilst more fragile than other technologies, they are more robust than the humans who might have them in their pockets…

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