Schneier on Security

Clive Robinson • May 7, 2025 11:51 AM

@ Bruce,

I checked the date on the article and it looks like it’s nearly a month late, for what is in the photo 😉

In the UK we’ve pushed out similar style hulls for the Royal National LifeBoat Institution”(RNLI) and as North See Support Vessels. Designed to move at speed, roll over and self right.

It’s hard to tell from the photo but it looks like it’s a composite hull made from GRP or similar (carbon fiber is not considered suitable for maritime use)

The article says dive to a depth of 60m… Where the pressure would be around 6 atmospheres in salt water (~1024kg/m^3) or ~600kPa or (6 times ~14.5) 87PSI.

So a quick head calc says 87PSI on an area of 1m squared (call it ~1500 square inches in a square meter, lets not go down the XKCD squares[1] rabbit hole to Australia) that’s a little over 60tons…

So that hull and superstructure can not be sealed let alone a “pressure hull” and there are a few other indicators it’s not exactly tying up with the story line.

[1] The trouble with English and simple units of area…

https://www.explainxkcd.com/wiki/index.php/3065:_Square_Units

Clive Robinson • May 7, 2025 3:46 PM

@ Mark,

With regards,

“Let’s see, drop one, send your ship away, and weeks from now…”

First put a couple or three nukes on board then rise up under a carrier group or other maritime convoy etc.

As I’ve mentioned before the ways in and out of the south china seas are not many nor are they really “deep water”.

A few weeks back a senior US military person advised Congress that the US needed hundreds of thousands of high capability drones to make the gap between China and Taiwan a broiling hell for a month whilst other –unstated– capability could be deployed.

I suspect China has been thinking about this and realised above the surface vessels are these days just sitting ducks not just to hypersonic missiles but swarms of low cost aerial drones. So realised submersed fully autonomous nuclear drones at depth are not really susceptable to either hypersonic missiles or aerial drones.

It’s something I’ve noted from time to time over the years that a “bottom sitting” fully autonomous drone/mine is with proper precautions very difficult to detect and they could just sit there dropped off the bottom of a ship for a year or more.

This is not exactly new thinking, back in WWII both sides used submarines for “mine laying” and they were reasonably effective. Detecting the subs basically fell to air bourn radar as the subs had to surface every day or so to recharge batteries and get fresh air in for the crew.

These days, you don’t need 80-95% of a submarine needed for the crew, and with nuclear power sources and high capacity batteries getting quite small and modern electric motors being very much more efficient…

Creating a bottom sitting sub / mine as small if not smaller than a family SUV would not be beyond the bounds of reasonable possibility.

Clive Robinson • May 8, 2025 2:43 PM

@ Mark,

With regards,

“I was not assuming end of the world – because anyone using a nuke will bring it all down”

I said nothing about the “end of the world” because the notion of MAD exited stage right when Trump was last in office and walked out of various treaties.

In part because China had never been a part of the treaties and Russia saw China as a potential threat at the time. Since then both Russia and China have spent the better part of the past decade developing “tactical” rather than “strategic” nukes as have India and to a lesser extent Pakistan.

Basically they see “tactical” being short range weapons somewhat like the old US Mil “Davy Crocket”.

In part this was because the effective yield of things like FAE/FAX has come up to a similar level and thus tactical nukes just a logical progression.

As such back then the ballistic path missile or aircraft flight path would say if it was a tactical or strategic nuke.

However the development of “Hypersonic” missiles and drones in the past couple of years of which China is arguably the world experts currently has made a significant difference. The newer flight paths are non ballistic and are much lower and flatter with the drones being more like hypervelocity cruise missiles capable of a degree of steerable / evasive manoeuvring rendering most current and some proposed missile defence systems moot.

Also small tactical nukes as an EMP weapon are an effective way of removing commercial drones “from your skies” and off of the battle field before they are out of the transportation boxes/crates.

Clive Robinson • May 9, 2025 2:33 AM

@ Moderator this got a 429 response then on retrying a “held for moderation” response at 07:30BST

@ not important,

To in part answer your question of,

“… then how it get move from static to dynamic stage?
through sound command?”

Sound travels an incredible distance under water and the higher the pressure thus effective density of the water the further it goes.

It’s known that the early US space capsules had a bomb in the top, the purpose of which was to explode below a certain water depth. Because Navy experiments had found that the sound would travel something like a third of the way around the globe and that sub sea microphones could by triangulation could locate where.

The Navy research was based on research for mines. During WWII some mines were detonated by the noise a ship made in the water near/above the mine.

So using sound as a communications method under sea would certainly be practical.

But also do not rule out EM communications…

Nuclear subs can pick up very low frequency radio signals that are just outside of audio frequencies in the low tens of kilohertz. There are known “ELF” transmitters due to their antenna size in the US and UK.

Further subs do send up VHF and UHF buoys at pre arranged times to talk to “Low Earth Orbit”(LEO) satellites as they pass over every 90mins or so. Such systems would actually be difficult to jam if using various “Low Probability of Intercept”(LPI) systems.

It’s been documented in the UK Press about how such systems could be used with the UK Nuclear Defence system.

Interestingly sea water is quite transparent to infra red light as well. So the question of if at 60m / 200ft maximum depth the light from a modern high intensity IR laser would be reliable for communications?

Clive Robinson • May 9, 2025 3:47 PM

@ mark,

With regards,

“but any use of nukes will invoke the other side’s nukes”

Sorry but there really is no evidence to support that view point.

Back when it was just the US and CCCP with nukes the notion of “MAD” was raised but a quick analysis of it reveals it to only work in a “two player” game.

Since then five countries with production capability that possess
them have signed up to the non proliferation treaty,

China, France, Russia, UK, and US.

However other production capable nations that are known to possess them,

India, (Israel), North Korea, and Pakistan.

Are not signed up.

Then there are the countries that have been given / loaned nuclear weapons from other nations (mostly from US),

Belgium, Germany, Italy, Netherlands, Turkey and (Russian supplied) Belarus

So it’s now a game with 15 players at least.

And I suspect if the Ukraine comes out the other side of the current war, and get back on their feet, they will go back to producing nuclear weapons again. Rather than rely on hollow promises from the UK and US as they once did.

As I noted China, India, Pakistan, and Russia have made it clear they regard tactical use to be acceptable not just as doctrine or policy but as a primary response.

Not so long ago China and India were squaring off and prior to that China and Russia, basically over land and resources. Russia provided India with the base technology

And as I’ve mentioned before Pakistan got it’s technology via A. Q.Khan who basically stole it from a Belgium institution. Then after developing Pakistan’s nuclear capability tried to sell the technology out of Switzerland to quite a few other countries. Three known buyers were Iran, Lybia, North Korea and others such as Iraq “suspected”.

It’s interesting to see what North Korea is upto, simplified their small nuclear capability is the equivalent of a “Keep off our Grass” notice to the US State Dept and US DoD. If you analyse the game between North Korea and the US, you are left with the conclusion that North Korea is actually “the rational player” with historically the US being anything but due to the behaviour of Congress.

The problem with three or more players in the MAD game is the “small player” issue providing they are not seen as a threat by other countries they can effectively attack another “small player”

Consider what would happen if India attacked Pakistan… Pakistan would retaliate to a similar level. No other nation would come to the aid of either of them. Thus if they attacked each other with tactical bombs, missiles, or drones then it’s most likely they would be left alone as far as other nations nuclear deterrents are concerned for obvious reasons.

If however India attacked China or China attacked India the situation would be quite different.

The chances are that in the very near future Japan, South Korea and even Taiwan who are all nuclear weapon development capable and already have systems capable of delivery developed, will see China as an existential threat and Russia and North Korea in a similar view. Thus they will develop and deploy nuclear weapons and have itchy trigger fingers.

Oh and don’t forget Europe more than half of EU states are nuclear weapon and delivery systems manufacturing capable… And due to noises coming out of the US Executive are going to follow the British and French and become “deterrent capable”.

The days of MAD by long range bomber and ICBM are well and truly over and those thinking the world will get destroyed “if the button is pushed” are quite a bit out of current events/thinking.

Since the Korean war in the 1950s we know that the US Military have regarded the use of nukes of any kind acceptable to prevent loss. It’s US politicians that have stopped them being used.

If political thinking changes then the night sky is going to get a few false sun rises in the not to distant future. Either over Asia or the Middle East is most peoples thinking but I can see it happening in Eastern Europe quite easily.

Clive Robinson • May 10, 2025 1:46 AM

@ not inportant,

You ask,

“Q: to send I understood but how to receive? Are buoys connected to sub?”

To answer there are three aspects to consider,

1, The physical relationship
2, The communications relationship
3, The time element

Stripped down the physical relationship is how the buoy is deployed with regards the vessel.

The first aspect of which is if it is tethered to the vessel and therefore reusable or if it’s free floating and will drift with the prevailing current and wind at the surface.

The communications relationship options can be seen to have their roots in hobby and Amateur/Ham radio and later commercial and military communications. With each communications path seen as individual steps or links. Each being a Shannon Channel with leakage to third parties.

The links out-bound are sub-buoy, buoy-sat and in-bound sat-buoy and buoy-sub. Only some of which might be needed depending on the real time requirement.

Consider a simple update report is mostly about data that is nowhere near real time. It could be loaded electronically in a free-buoy and released to rise slowly thus drift, or to propel it’s self, away from the sub location before breaking the surface and communicating with the sat before sinking or in other ways removing it’s more observable presence.

An urgent two way communications is at the other extreme and that would need all links in the path to be in near realtime. Although it can be done with a free-buoy it would be more likely to use a tethered-buoy that is effectively winched up and down from the surface.

But does the communications need to be “two-way” even in an emergancy?

The answer is mostly “No” you simply use redundancy and probabilistic methods such as “Forward Error Correction”(FEC) to ensure the data gets delivered.

Thus you in effect have two systems “a parrot” and “a repeater” both of which have advantages and disadvantages. Either way the use of “Low Probability of Intercept”(LPI) methods would be used.

However care has to be exercised… because satellite “over pass” times are very likely to be known to an opponent. The less the number of satellites the less real time communications can be and the less the degree of freedom you have to hide in. Consequently the easier it would be for an opponent to do an attack based on “noise present” correlation. That is you average time slices to pull out an LPI signal from other signal and noise sources. An opponent does not need to be able to understand the signals just be able to sufficiently distinguish them to locate the position of a buoy. Such techniques were first developed in WWII with what became “traffic analysis” and also early submarine tracking not just by “HF Direction Finding”(Huf-Duf) but into the Cold War with hunting for acoustic signatures under water with 1.5Km or longer “towed array hydrophones” from the backs of ships or “Hunter-Killer” class submarines.

There is also a more modern system where light in an optical fiber gets modulated by any noise and by use of “Time Domain Reflectometery”(TDR) and similar location information derived. This technique came into the MSM at the begining of the year with respect to cable cutting in Europe by Chinese/Russian vessels,

https://www.bbc.co.uk/news/articles/cn52rglxr62o

However it was known earlier as a way to detect geological events that could give warnings of earthquakes from work done at the UK’s National Physics Laboratory in Tedington SW London (where the real original of the World Wide Web was developed and used), and is adjacent to the Admiralty Research Establishment as was,

https://www.bbc.co.uk/news/technology-61506705

Clive Robinson • May 15, 2025 7:23 AM

@

With regards,

“Is it possible to have IR repeater which could pass down signal from 60m from initial source to more 60m”

Sorry I did not reply earlier.

The answer is both yes and no, depending on which way the data is going.

For data down to the submersible it just requires a tethered buoy that “does not break the surface”.

So the submersible winches it out and pressure sensors indicate when it’s say 10ft below the surface. It then has a better “receive path” from an air or space bourn transmission source. The data can then be relayed down the winch cable.

However sending data in the opposite direction from the submersible up would be considerably harder and would be based around using a multiple beam split laser source each beam placed a fair distance from the others and likewise spread apart sensors to receive it. In effect using a mix of MIMO and interferometry. A buoy to do this would be fairly large in size and require stabilisation, thus being less than stealthy in use.