Schneier on Security

Clive Robinson • August 10, 2019 12:12 PM

@ CallMe…, Name.Witheld…,

Proprietary crypto is at best a curiosity and at worst snake oil

All crypto algorithms are “proprietary” untill subject to “peer review” and indepth testing.

However experience has taught me that original thought is worth looking at for two reasons.

Firstly it opens up new possibilities. Secondly even when totally bad it usually gives up new methods and insight.

Oh and whilst people are running around worrying about “Post Quantum Crypto” there is a rather more important and immediate problem that is facing us,

All consumer devices have the security end points on the device where the communications end points are. This means that even the most secure of communications applications running on consumer devices are very easily rendered usless because an attacker can simply get at the “plaintext User Interface”. Thus such devices can not ever be secure.

Which means consumers can not have the right to privacy with the electronic devices available to them. That’s not a “Future might be” as with “post quantum” it’s very much a here and now very definate real and persistent issue and has been for quite some time.

Which means for consumers to have privacy they need a non electronic device, that moves the security end point off of the consumer electronic devices that are also communications devices, which these days is rapidly approaching all of them. This is because the “System on a Chip” (SoC) devices available for IoT and most other consumer devices come with comms on the SoC as standard.

Thus we need to look into crypto systems that do not need consumer electronic devices to work. The simplest of such options is “Pencil and Paper Crypto”. We know that the One Time Pad (OTP) and One Time Codes (OTC) are considered “theoretically secure” and thus if used properly “practically secure” as well.

Thus Paper and Pencil codes and ciphers that are theoretically secure are of interest to consumers that want to establish their right to privacy.

Further the sooner they become used then the sooner this “back door” / “front door” / “golden key” nonsense can be consigned to the trash can of bad history again.

Clive Robinson • August 10, 2019 6:24 PM

@ Whomever,

I’d say they at least need a device that hasn’t been targeted and which can no longer easily communicate or become compromised wirelessly.

Where are they going to get it from?

Not being funny but there are probably more people now, that don’t know how to program a VCR than since they were first invented.

Consumer technology has changed so fast that few outside specialist occupations now know how to use things like the command line any longer. So older technology that has not got overly complex OS’s full of vulnerabilities/backdoors and SoC devices with comms interfaces is not in the average consumers abilities let alone available to them.

If countries like the UK and Australia pass legislation making encryption backdoored etc, how long do you think it will be before they pass legislation making all consumer equipment in effect back doored. As it is it’s getting hard to buy consumer entertainment equipment without Internet connectivity of various forms and with blue tooth etc. With many vendors adding microphones and even cameras both of which can “dial home”, privacy in the home is becoming effectively Orwellian.

Whilst there are people around who can program 8bit and 16bit microcontrolers that are capable of doing various forms of encryption, but without having in built off system communications. The chips are getting less and less common. You can now buy for the same price fully functional 32bit SoC devices in the 2USD price range that not only have the RF comms hardware built in they can also run *nix virtually out of the box. You see them poping up all over the place in IoT devices.

Which means that a generally available consumer device will be either backdoored or easily “owned”. Thus of little or no value privacy wise.

If we are to retain any measure of privacy then it is the ordinary consumer we should be assisting, not the specialist. Because specialists are very few and far between thus a very small fraction of the general population. Therefore specialists are effectively of no concern to SigInt agencies, unlike the general population under the modern paradigm of “collect it all”.

Clive Robinson • August 10, 2019 6:52 PM

@ Anders,

I commented on this new Boeing bad software story last week.

The fact that the software design and implementation on two different Boeing aircraft both show a lack of “quality control” is rather worrying.

Thankfully even though I live not that far from one of the busiest airports in the world (LHR), I am not under any flight paths.

Clive Robinson • August 11, 2019 6:22 AM

@ gordo,

Which means to say “track it all”, “tap it all”, “share it all”, “break it all”, “fake it all” and “direct it all”.

Which as a consequence leads on to,

“Control you all”

The consequences of which fall into the three broad categories of “surfdom”, “flight” or “fight”.

As we see from the nightly news eventually the first gives way to the other two. The second can also be described as from “frying pan to fire” and only lasts as long as there are places to run to.

History shows that ultimately war will occur be it at home as civil war or abroad against some other nation as a war of conquest and enslavement.

People then say “never again” untill of course it all happens again. As was observed by Wendel Philips at the begining of 1852,

“Eternal vigilance is the price of liberty; power is ever stealing from the many to the few. The manna of popular liberty must be gathered each day or it is rotten. The living sap of today outgrows the dead rind of yesterday. The hand entrusted with power becomes, either from human depravity or esprit de corps, the necessary enemy of the people. Only by continued oversight can the democrat in office be prevented from hardening into a despot; only by unintermitted agitation can a people be sufficiently awake to principle not to let liberty be smothered in material prosperity.”

I guess that today would not surprise Alphonse Karr, who in effect wrote history’s epitaph with,

Plus ça change, plus c’est la même chose

Clive Robinson • August 12, 2019 2:56 AM

@ MarkH,

@vas pup, @Wesley Parish and myself have been discussing the Russian missile test explosion and radiation burst over on the previous couple of Friday Squid pages and the US Pluto and Tory projects,

https://www.schneier.com/blog/archives/2019/08/friday_squid_bl_689.html#c6797075

Such an engine was shown to work in the US (Tory) and it had the capability of keeping a “hypersonic cruise missile” up for months, thus turning it into the capabilities of a globe spanning ICBM for less cost than an IRBM at the time.

The US Pluto / Tory projects were cancelled after seven years not because of the very real danger they represented but due to a fear that Russia would be forced to develop it’s own system and there was then unlike ICBMs no known way to stop such hypersonic missiles even thought of (and it’s highly doubtful we’ve made any progress on that front since).

One of the lessons many have either not learned or have forgoton is the great asymmetry between the US and Russia. The Russians had a dangerously pragmatic approach where safety/security of nuclear devices was very low on the list of priorities with simplicity / reliabilty much higher. The opposite was and still is true of the US and to a certain extent other Western nations that developed nuclear weapons. The problem is that other than a few “field artillery” type nukes such as the Davey Crockett it appears that less than thirty percent of US nukes were actually likely to function if deployed. Figures for Russia nukes are likely to have been much better, however, the early Russian delivery systems we now know had a habit of blowing up on the launch pad…

Clive Robinson • August 12, 2019 4:38 AM

@ Mark H,

… which seemed to suggest that a rotary-dial Kaba model had a sort of generator inside, obviating the need for a battery to power the electronics!

Energy does not spontaneously appear, the generator is simply an inefficient transducer for converting one sort of energy into another.

People have sugested other internal energy sources such as “clockwork” but that to runs down unless you rewind it. Likewise dropping magnets through coils under gravity and similar.

The problem is what happens when an incorrect combination is entered. You’ve run the energy supply in the lock to the generator down and eventually the lock will not function.

This would leave open the possibility of hand crank or on the back of the rotary dial etc. In other words the generator is driven via a shaft from outside. However that gives rise to other security issues such as the shaft being bent or broken, or over cranked such that the generator over volts and burns out it’s self or the lock electronics.

Which means in the case of the nuclear repository lock the primary requirment of “Must always open on correct combination entry” fails.

It’s also the same primary requirment for military use safes. Where being able to get at the contents or verify the contents are still there, is a primary requirment. Which means the likes of “relockers” and other similar anti burglar techniques can not be used.

Clive Robinson • August 12, 2019 6:21 AM

@ Whomever,

You could probably set this up with a raspberry pi and a camera on top of any existing messaging app.

And that’s where it stops being “ordinary consumer” usable.

You can look up on this blog or Github “Tin foil Chat” (TFC) that will give you the qualities we desire. It’s one of the best examples around designed and built by Markus Ottela when at the University of Helsinki, Finland, it’s still up on GitHub and just reading the documents alone should give you a good idea not only what it can do but the various parts involved and the work required to get it up and running. That is unfortunately “it does not work out of a shrink wrapped box” which is what the majority by far of those who would want to use such security would need it to do.

The other problem is unlike an old mobile phone, calculator or similar, carrying it across a border is asking to be stopped and asked awkward questions. Because it does not look like something you would find in a travelers luggage. It’s why I suggested a while ago that for the optical data diodes and light pipes TOSLINK components [1] be used As these are comparitively much more common as they are used in the recording and other entertainment industry equipment also home studio and more up market home hifi using seperates. They solve not just noise issues, but ground loop, and galvanic issolation issues, that occure quite frequently in outside events run by generators or across floors in multi story buildings. Such bits if made to look like “USB to Optical” parts can be more easily passed especially if “music software” is on the computer etc.

I even suggested that making them commercially as USB to TOSLINK converters would actually make them a product with more than one market to sell into. Which would help with the “shrink wrap packaging” issue.

[1] TOSLINK or Toshiba Optical Link also called “Optical Audio” is based on the Sony / Philips Digital Information Format (S/PDIF) protocol. Quite a few high end “HiFi Seperates” and “Studio Equipment” have the interface as standard on them,

https://en.m.wikipedia.org/wiki/TOSLINK

Clive Robinson • August 12, 2019 5:49 PM

@ vas pup,

Clive: Do you remember that article from BBC related to conditions in the prison in Norway?

You mean this one,

https://www.bbc.com/news/stories-48885846

Clive Robinson • August 12, 2019 7:36 PM

@ EvilKiru,

How about an electronic lock where the key provides the power?

The problem is that involves pins connected to the circuitry which makes it vulnerable.

You can look up the “USB-Killer” device. Put simply if you can generate a high enough voltage at a low enough impedence you can dump considerable energy into the circuit, that it was never designed to handle.

Whilst you can try to limit the inrush of energy, it has to go somewhere. As neither capacitors or inductors disipate energy –only store it– any protection circuit needs resistance that is physically small with fast rise times. The down side is physically small resistors have a very small energy disipation. This means either a complex system of graded low pass filtering into capacitively coupled loads to stretch any rise time to the point that active semiconductors such as transorbs (equivalent of back to back zener diodes) that have nano second rise times, can start switching the energy away from the sensitive circuitry.

But what ever you do, you do end up with a series resistance in the protection circuit that acts as a “back stop” That unfortunately under normal usage conditions disipates a big chunk of the energy. The net result is instead of say using a three volt battery in the key you would have to use twelve volts. Which means that there would be 3I power consumed by the lock circuitry and 9I power disipated in the series resistance of the protection circuit… Which at 12I drawn from the Key Battery is not good for it’s life expectancy…

Having designed circuitry with very fast rise times and quite high energy (think cascade UV triggered spark gaps and water dielectric capacitors) to quite literally explode fine silver / copper wire like tubes into high preasure plasma. Basically more “box bashing” precision mechanical for optics than electronics, that also just happens to have some electrical components built in for instrumentation protection. Not a patch on Sandia National Laboratories Z machine that goes to the edge of fusion, but sufficient grunt for people to be somewhere not close to the business end when fired. Which has given me some appreciation of a number of the issues involved with “poor man’s EMP”…

Clive Robinson • August 13, 2019 3:50 AM

@ Wesley Parish,

And not forgetting the heavy metal environmental damage locked up in the shielding …

That would not be a problem…

Because there is no shielding around the reactor in such designs.

So as the thing flies over your head it sprays neutrons into everything. Whilst non organic structures remain intact, the organics especially the “meat sacks” get a good grilling…

So effectively it does not need a warhead, it just flies backwards and forwards at hypersonic speeds across nations or even continents spreading death but not destruction along it’s flight path, as what might be seen as an endless neutron bomb…

As such once up to a certain speed and the reactor up to a nice rosy glow, there’s nothing realy stopping it for not just hours, or days or weeks but months…

There is the quote from the Bhagavad-Gita Hindu sacred text that Oppenheimer made infamous, that would make appropriate reactor start words,

Now I am become Death, the destroyer of worlds

In effect as it flies the four horsemen of the apocalypse are brought together in it’s foot print,

They were given power over a fourth of the earth to kill by the sword, famine, and plague and by the wild beasts of the earth.

The latter being the bacteria and roaches that are about all that will survive and thrive in what remains after the famine and plague of radiation sickness. In effect the lucky ones being those who die by the sword, because it is a quick death in comparison.

Clive Robinson • August 13, 2019 7:07 PM

@ vas pup,

For better or worse, small but incredibly influential groups can change the course of political debate.

Politics is just the current incarnation of this problem.

It’s one of the reasons I have a distinct lack of faith in economists and similar predictors of human behaviour.

There is often a number of quite simple reasons people become “irrational actors” and it boils down to “distortion of their Point of View (POV)” either intentionally or not,

1, Lack of information which distorts their POV.
2, Over trust in individuals which distorts their POV.
3, Incorrect interpretation of minimal information which distorts their POV.
4, Not wishing to, or lacking the ability to confront a source of information that has some level of trust.

Are just some of them.

As I’ve mentioned in the past when an event happens that is witnessed by N people, the reality is there is atleast N+1 points of view where at least one is not known.

The one least likely to be known is what we like to call “the actual truth”, and a little thought on the matter shows that it is not possible to know the actual truth but at best some aproximation to it.

Even in science we have “measurment error” that can distort findings[1], and more subtly limits of meaure[2] so what chance do ordinary mortals have?

It’s also why one witness to an event can move the “apparent truth” or “agreed truth” away from the “actual truth”. We even have a saying that reflects this of “With each retelling the tale grew taller”. Take something like the colour of a coat. Most people would agree with “red” in broad daylight, but what about lower light levels? Then “dark blue” might be “black” or “dark green” or even “charcoal grey” depending on who says it first. Thus with retelling what was blue becomes green etc.

Thus there is no reason “to lie” just tell a slightly different verion of the “apparent truth” others will quite happily go along with it and usually end up actually believing it.

The reason people don’t then like to change their mind back is it makes them look unreliable or even dishonest. Something defence lawyers rely on as a trick to exploit to discredit witnesses in the eyes of a jury.

Actual testing shows that “eye witness accounts” are usually not very reliable, and that witnesses will often only correctly identify individuals about one time in four, even getting the persons sex wrong way more often than you would expect.

[1] It’s why science likes to repeate experiments usually with different starting conditions to ensure any “law” is sufficiently robust and within certain limits (often called “linear behaviour”). As a mater of fact every time you stretch a spring even minimally you fractionaly change it’s properties due to amongst other things “work hardening”. However usually such a change is very small and below the threashold of measurment for an individual test. But as hundreds if not hundreds of thousands of actions of the spring show it eventualy fails in some manner and has to be replaced. As this is also fairly predictable we have the idea of “preventative maintainance” to stop amoungst other things aircraft dropping out of the sky.

[2] Limits of measure can actually be seen as well as reasoned out. If you take an object you can measure it’s dimensions with a “measure” that is of similar dimentions to the object. However if the “measure” is smaller than the dimension being measured then it has to be repositioned repeatedly, obviously this will cause errors. Likewise if a measure is larger than an object then an estimate has to be made. An example of both would be measuring the dimensions of fine wire on a 1500ft real with just a 12 inch ruler as the measure.

Clive Robinson • August 15, 2019 8:43 PM

@ Alyer Babtu,

I will stand down my orders to put black tape over the monitor screen 🙂

Don’t do that, the screen might not be able to see you… But that camera hiden in the smoke detector in the ceiling “Will see all” if you don’t use the black tape.

Also think about the Douglas Adams idea of “Peril Sensitive Sunglasses” that go totally black at the first sign of danger so the wearer does not see anything to stress them out.

There is now enough scientific evidence about the stresses and strains of not just the computer displays, but also the content.

Thus think about all the retinal and psychological damage that black tape is saving you from…

But also your insentive to turn it on goes fairly quickly to zero, so there is the carbon footprint that black tape is reducing.

Heck it might even encorage you to go out side and get a half hour of parambulative cardio excercise, and allow sublight to top up your vitamin D levels to stop depression and all sorts of other maladies…

So you stick with those health and environmental benifits of good quality black tape 😉

Clive Robinson • August 16, 2019 5:49 PM

@ vas pup, Sherman Jay,

Is it possible to prevent speakers can be turned/reversed into microphones for audio surveillance by using of semiconducter in speakers electricity supply line which will let only one direction electricity passage

First of the fact it works has nothing to do with the “direction of electricity passage”.

It has everything to do with the rate of change of the speaker coil around the magnet. Thr coil can be moved under two influences,

1, The electromotive force from the current flowing in the coil.

2, Any mechanical displacment force on the coil caused by prrasure on the cone/diaphragm.

That is it is acting as both a motor and a generator. Thus the current in the coil is the sum of the input current from the audio amplifier plus the displacment current caused by other sounds applying mechanical preasure on the coil.

It’s a little late in the day for me to derive a formular for this so I’ll leave it as an excercise for the reader;-) But all you have to do is starting with It=Ia+Im substitute equations for the amplifier current Ia and mechanical movment Im so it can not be that hard 😉 providing you remember that as complex numbers are involved you are dealing with vectors not scalars :-S

However you also need to consider that the junction of the Amplifier pull up and pull down devices and the terminal on the speaker cone are not at an electrically or time equivalent point (they have a lead that has inductance, capacitance and impedence, between them which acts like a short length of transmission line). Thus as with “standing waves” in RF transmission lines Ia propagates to the load that the speaker coil inductance is, thus some percentage will be reflected back towards the source of Ia. Likewise Im propagates from the coil where it was generated due to the rate of change of position of the coil towards the source of Ia. This propagation is why the signals can be seperated with a return loss bridge in the transmission line the speaker lead effectively is.

Interestingly when the mechanically induced signal Im gets to the junction of the amplifier pull up and pull down devices, it will also see the components used to generate feedback into the amplifer input to set it’s gain and frequency responce thus stability. That is the feedback circuit will feed back a fraction of the mechanical displacment current Im to the input of the amplifier…

In essence this is exactly what DC motor speed controlers in battery supplied drills etc do.

So in practice you can put a circuit between the input signal to the amplifier and the amplifer feed back input and extract a small fraction of the mechanical displacment signal Im.

The only way to stop Im propagating backwards is to make effective isolation that does not require feedback to maintain stability etc.

Clive Robinson • August 17, 2019 5:12 AM

@ Wesley Parish,

I would’ve thought any time you can differentiate output from one section of a screen from that of another section, you can differentiate objects in that “field of vision”.

Yes and no. Hold up a thin piece of material that whilst quite opaque is not transparent. On any one point you see all the light that falls upon it from all angles. The result is the vector sum of all those photons. All sources of radient energy are in effect point source isotropic radiators with the maginitude droping in any direction as 1/(r^2). That is for any given angle of radiation the area it illuminates goes up by r^2. From this you can work out how far an isotropic light source has to be from a screen to illuminate the whole of it and at what intensity difference across the screen.

But even if the parts of the screen can show the magnitude they cannot show the directionality of the individual sources just the sum of the magnitudes at any given point. Whilst it is possible with just one close source to calculate at which point it is closest to the screen once the sources become more distant or the number increases this task becomes more and more difficult. A process most are grateful for when working in buildings because it very quickly alows isotropic point light sources to act together to provide near constant illumination on surfaces like desks etc from as little as 2m/6ft away (10ft high room 4ft high desk).

To get an image of any quality you need to get the directional component of the light sources. The easiest way to do this is with a fully opaque screen in front of the screen you are using for your observations such that no light falls upon it. You then make a very tiny hole in the totaly opaque screen. This only alows a very tiny angular range from each light source to fall on a very small part of the observation screen thus a very high component of directional information is obtained. Which is why you see the image not a general glow caused by a lot of sources from all directions.

Whilst the pin hole in the main does not bend the light passing through it the image resolution at any point on the observation screen is proportional to it’s size. That is the smaller the hole the smaller the angle of illumination is thus the greater the resolution. However the size of the hole also determins how much light from each source does reach the observation screen, thus the smaller the hole the less light there is. So you quickly get into a game of diminishing returns with a pin hole.

Thus you have to work out other ways. One of which is to use tubes that “funnel light” in only from certain directions and you can see this in nature in certain eye types. A more effective way is to bend light to bring it to a focus and this can be done with lenses or shaped reflectors. These maintain the directional information but gather light from very large areas and bring it down to very small areas thus giving light magnification. But the important point to note is the maintainance of the relative light angles. If they are not maintained you have at best fuzzy images rapidly degrading to just a directionless magnitude sum.

If you consider flat screen displays as a general rule they are designed to give the widest range of viewing angles possible which means the rule of reprocicity applies. That is the angle at which you can see the light emmitted is also the angle of light that it would be sensitive to…

In short you would need some way to focus the image onto the screen as the barest minimum requirment.

Clive Robinson • August 17, 2019 1:50 PM

@ ,

<><>

The key paragraph to read in the article is this one,

Receiver phased arrays, use variable phase delays from each pixel/antenna to constructively interfere signals from one direction only, light from other directions to a greater or lesser extent cancels out in the receive signal.

If you think about it, is syntherzising a tube down which light can only arive from a very narrow angular apature (the probs of which I described in my earlier posting). The tube is effectively scanned across the field of view as rapidly as required to get a suitable contrast image, thus the speed depends on the ambiant light level.

I actually designed a 3D camera to shove in nuclear reactors that kind of works in the reverse of this[1]. In a low light or dark environment you can rapidly scan a point of light such as a laser beam rather than a tube across your desired field of view. As there is only one “point source” reflecting the light back you don’t need to have directional information at the sensor to build up an image as the directional information is derived from the scanning head (think of a laser light show where the beam is scaned rapidly, there are now some quite expensive 3D scanners that work in this way).

[1] It just so happens the original John Logie-Baird TV camera worked this way but rather than using the line scanning of today it used a disc with thirty lenses set in a single turn of a spiral,

https://en.m.wikipedia.org/wiki/John_Logie_Baird

I used two spining bar reflectors the fastest that gave X-direction (horizontal) scanning the other Y-direction (vertical) scanning. The Z-direction (depth) was derived by using a bar of photo sensors under a special lense.