Schneier on Security

Clive Robinson • April 1, 2025 11:34 AM

@ Bruce,

April 1st not a good day to ask,

“We need answers for both iPhones and Android phones.”

Whilst iPhones all more or less work the same way, that is certainly not true for Android phones where a manufacturer “customizes” not just above the OS but below the OS as well.

But “solid state memory” is a bit problematic, as a general rule of thumb you can not “erase files” on it due to “wear leveling” that still goes on even though reliability is a lot higher than it once was.

My advice in the past and still is today, that when you cross a boarder, assume the following will happen (actually rarely unless you are a PoI),

1, Your phone will get taken from your view and scanned and malware added.
2, A record of your ID/Passport will be matched to SIM and Phone serial numbers and put on record.
3, A record of your various bio-metrics like face scan finger prints etc likewise will be linked.
4, Within 24hours your data will get sucked up from data brokers to use in evaluation and interviews.
5, Any “social media will be scanned for political views.

You won’t be able to clean your phone up so just throw it away…

So my advice is,

1, Don’t take any electronics across a boarder.
2, Buy cheap non smart when you get there or have it delivered by the likes of Amazon.
3, Have either a traditional pocket diary/phone-directory with “essential numbers”.
4, Put all your other contact details and document scans up on a web mail or similar account.

When you leave factory reset the phone and computer and either chuck them in a refuse bin or just give it to someone to use. In some places just give them to a charity so they get reused.

However since Win10 getting a computer up and running without the Internet and a Microsoft spy-on-you account is not as easy as it once was.

Further you can nolonger just walk into a corner shop and pick up a Linux Magazine or book with a “Live-CD/DVD” on the cover.

Especially with laptops with CD/DVD players getting less and less common.

But there are things like “Rufus”,

https://rufus.ie/en/

To “pop an OS on your thumbdrive” or smaller (though phones are nolonger having memory card slots as standard).

Put bluntly the “Spy-On-You” Criminals, Corps, and Governments are winning the technology battles against ordinary mortals who travel across boarders and raise “curiosity”. Simply because consumer devices are cheaper to make without them…

I have the (dis)advantage that medically I’m a “no fly” these days, so don’t get to meet the sort of “Customs and Immigration” that do these sorts of things (just Law Enforcement). But I do have friends that run into them a couple of times a year…

So I’ve “de-tech’d” my life for walking around etc.

Clive Robinson • April 1, 2025 12:01 PM

@ Paul Sagi, ALL

With regards,

Likely there will be a market for phones that irretrievably wipe all data after a few failed password attempts.

There was and there still is, as some people like lawyers, Medics, Religious Ministers have a “legaly recognised duty of non disclosure” and many working Professionals have a legally binding contractual duty of “Non-disclosure”.

However if you listen to just,

1, Law Enforcement
2, Politicians
3, Civil Servants
4, People with cognitive bias
5, The MSM who reflect them all

Then the only people wanting it are Serious Organised Crime or Worse.

Thus Law Enforcement quite unlawfully set up companies providing such phones which then get “cross boarder surveillance” with little or no oversight through “Mutual Legal Assistance Treaties”(MLATs).

Look up EncroChat and earlier Australian / FBI devices.

I advise against anyone using “secure apps” on Phones or Smart Devices that have any kind of Communications externally.

Because they form “part of a system” and most of that has so many “weak links in the chain” any security in the app is easily bypassed.

Worse such Apps are the equivalent of “bullseyes on your back” and just inviting trouble. Even WhatsApp is viewed with suspicion by Law Enforcement looking for an excuse to make your day worse (or week under anti-terror legislation, or just bounce you back by deporting you at your own expense).

Clive Robinson • April 1, 2025 4:49 PM

@ ALL,

But it’s not just border crossing you have to worry about

How about any doorway?

You step out of your home and you get seen by your or your neighbours Amazon or similar doorbells as you open the door.

Than you get seen by many more and street CCTV, traffic and even parking cameras, not to mention all the insurance companies getting all excited about surveillance in your car and of all the other cars around you. All watched by what they hope the next Generation of AI will bring them which is ways to whack you with double or triple the premiums or deny claims (just as is starting to happen in healthcare).

Then there is surveillance in the places you work, shop, eat, and even excercise.

All,

“For your health and safety…”

And triple the profits for half the costs…

But are you safe behind your front door?

Of course not… Which is why people are talking out about it,

“Privacy died last century, the only way to go is off-grid

From smartphones to surveillance cameras to security snafus, there’s no escape”

https://www.theregister.com/2025/03/31/privacy_dead_opinion/

Let’s just say talking about “Going Off Grid” to get “Privacy” was untill fairly recently seen as “paranoia talking” now not so much. Especially when even your Fridge demands to be connected to the Internet, and your TV has a microphone and camera in it to see and hear what you are doing as you watch what ever it is you watch.

Oh and don’t forget your “Smart Meters” that can tell not just what you are using but again for some of it what you are watching or listening to…

Then there is all those WiFi and Bluetooth transmitters being used as “RADAR” system emitters knowing when you “scratch your bum” etc.

The way things have become even knowing what hand you wipe your backside or pick your nose with can be “monetised”… And yes no doubt how often you belch or emit other gasses is on somebody’s list… Gross yes, but if there’s profit, it is without doubt “The American Way” to grab it…

Clive Robinson • April 4, 2025 8:07 AM

@ Paul, ALL,

With regards,

“… it helps because u can “hide’ the info between the other archives.”

Err no, it’s more likely to help you into further interrogation.

Files and information build up on a storage device in recognisable patterns it was likened to “geological strata” or “anthropological strata”.

I more generally explain it less accurately “like an odd game of Tetris”.

In effect those who have your devices “can dig back” and look for inconsistencies in patterns in the filesystem that give other patterns that give further “probative evidence” against you.

The filesystem data is technically “Meta-Data” but the “patterns” are “Meta-Meta-Data” which is a concept many have trouble getting their heads around, even if they are aware that it or even it’s concept exists.

There is little written about this type of Meta-Meta-Data and its analysis, but at the foundation levels it is a lot like “Traffic Analysis” (which it is a proper subset of when considered logically or mathematically).

What you have to understand is that,

1, The patterns they look for can be found by automated systems thus do not require an “expert to operate”.

2, You have no idea which patters they look for, and you are probably unaware of them as they will get treated as at a minimum “trade if not state secrets”.

3, Your ability to synthesise such patterns even if you know all of them is minimal at best[1].

4, It would be very very easy to make a mistake, with just one file content that gives a sequence that falsifies the pattern you have tried to synthesise.

Thus you would do better to do the equivalent of,

“Build a new system from backups”

Where the backup system “restore” orders files by a “file system attribute” such as “file creation time” or “last access time” with an “oldest first” ordering.

If asked you just need to say “new laptop” etc. Because the pattern it produces is a form of “optimal” layout on mechanical hard drives that were used by “tech support” for years.

Microsoft even built a variation into that venerable old tool “defrag” in Dos 6,

https://www.easydos.com/defrag.html

We used to regularly for non NTFS drives[2],

Prep a new drive even if “new and fresh out the box”,
1, Secure Wipe new drive.
2, Low level format new drive.
3, High level format new drive.

Protect user data on old drive,
4, Make secure bit-level backup.
5, Make secure File level backup.
6, Put backups in secure storage.

Then prep the user old drive
7, Remove “sensitive files”.
8, De-Tail files on old drive.
9, De-cruft the old drive.

Then secure user old drive
10, Defrag the old drive.
11, Take File only backup.
12, Remove old drive and secure.

Finally “make good”,
13, Instal secure new drive.
14, Restore File only backup.

Which as you can see is an involved process and all to easy to miss a step, thus hang yourself.

What it does not do, is clean the registry, or clean out all that meta-data in executables (think that drop down with last few files you accessed). Also it does not clean out the meta-data in actual files. Remember those old “as a favour to NSA and Law Enforcement” file data formats Microsoft created with so much data in them… Well now think of all those other proprietary file formats doing the same thing. Only some like “pictures” have it DRM style with “Constalation of EURion”,

https://en.wikipedia.org/wiki/EURion_constellation

Or much less visible “water marks” embedded into images that are encoded with ID numbers, Dates and in some cases GPS location data.

It’s all to easy to miss just one and again “hang yourself”.

[1] The Meta-Meta-Data process is a little like the statistical analysis of “ciphertext” to find clues for a cryptanalyst to either “recognize a cipher type” or “walk a cipher back”. For nearly a millennium it was known from a short work by Arab polymath and assumed Muslim Al-Kindi, in his “A Manuscript on Deciphering Cryptographic Messages” that letter frequency in a permutated ciphertext had the characteristics of the plaintext in it. Not often said is that,

“You do not need to break the ciphertext to find the language it is composed in and sometimes the region the message composer is from.”

Just from “counting the letters and patterns” which come through. The fact that the Germans used very stylised message formats and language in WWII greatly aided breaking their ciphered communications.

You have to view it as a “One Way Process” having something that indicates a pattern does not give you the original information. Because it’s a very many to one “cause and effect” issue.

But also because it is a “very many to one” issue you can not easily make a match to a set of pattern either.

[2] The reason we don’t “de-frag” drives these days is that they are mostly all “journaling file systems” and this causes all sorts of problems. NTFS was in part “journaling” hence why the “No NTFS” dictum. For modern journaling systems you can either “go back” to Fat-32 or do more fun stuff with *nix systems and things like the venerable “shell scripts” with awk and tar etc. Personally I designed a “fake file system” and coded it up in C, that was in fact a linked list based on the chosen “file attribute” scrubbed that list of “sensitives” then used that to walk out to a single file “as a file system” (or part there of) doing all the de-tail, de-cruft, file conversion, filesystem Meta-data clean up etc on each file as it passed.

Clive Robinson • April 5, 2025 5:19 PM

@ Steve, ALL,

Then there is another reason not to go anywhere near some borders,

As noted above,

“It’s perhaps useful to note that if you live or travel in the US within 100 miles of the border, US Border Patrol may stop and search you.”

It’s technically called “the border zone” and even as a citizen you might not have any rights (see below).

But as a foreigner trying to do things correctly you definitely have no rights…

Which even if there is “no question” you were acting within the rules when you crossed into the zone, or even yesterday, you are not today, or tomorrow etc…

We only get to hear of a fraction of what goes on in border zones around the world, for instance read not just about this individual but the hundreds of others they mention,

https://www.cbc.ca/news/canada/british-columbia/jasmine-mooney-ice-detainee-canada-mexico-border-work-visa-1.7501758

Note the advice about dealing with visa and other issues, on “your land side” of the border where you are a citizen it’s generally good advice. But it does not necessarily stop bad encounters with your own countries border force.

Remember even if told by an official of the other country you will have to go to an office on the “other side of the border” legally that is “the wrong side” untill all the paperwork is correct and all I’s dotted and T’s crossed. As you will have no idea what all the most current I’s and T’s are you risk being imprisoned endlessly with no rights what so ever…

Worse some nations are changing the border rules so fast even immigration lawyers or court officers can not keep up…

If you think such rule changing is “political mantra” you would very probably be correct.

Also remember some countries have “border zones” wider or longer than the country, so when you include airport surrounds effectively near every where is “border zone” thus even as a citizen you might not have rights if you get “picked up”…

Somebody I used to work with was an “EU citizen” and Pre-Brexit had rights in the UK. They got pulled by the UK Border force in East London on the way to work one morning. The Border Force assumed the person was from South America and detained them “indefinitely pending deportation” because they “did not have papers” to prove who they were…

The thing is the person “detained” though having spent much of their early life and formative years in Portugal was actually born in the UK…

They have left the UK now and gone back to Europe and the last time I spoke to them they felt safer there even though Fascism and Far Right Violence was very much on the rise…