Schneier on Security

Clive Robinson • June 15, 2026 11:33 AM

@ Not really anonymous, ALL,

With regards,

<

blockquote>”Burner phones don’t really provide anonymity.”

<

blockquote>

Nothing ever really does if you “use it more than once”.

In some senses it’s a physical object that has the same issues as the informational object behind “Perfect secrecy”.

That is every time it is used it allows an observer to build up more correlations.

Eventually the correlations will be sufficient to progress the opponent’s “Find, Fix, Finish” process against you to the terminal stage.

Just one of the reasons this works is people forget all mobile phones have two electronic ID numbers,

1, The phone serial number.
2, The SIM subscriber number.

So put your old SIM in a new phone, it’s immediately linked. The opposite also applies new SIM in an old phone is immediately linked.

Whilst for some people, those who have access to,

1, Second hand phones.
2, Inexpensive SIM cards.

They might think the problem is fixed…

In reality the “authorities” will be able to “walk the supply chains” to the point you or your supplier gets identified.

Clive Robinson • June 15, 2026 9:29 PM

@ Not Really Anonymous, lurker, ALL,

As you note,

“Even only using them once isn’t good enough. There is still the location you call from and the number you called. Plus where and when you bought it or had it shipped.”

There are many layers to consider it was something I did not want to dig down through in just one post otherwise it might be the whole thread 😉

But you can including the pattern of how you turn phone on to when you use them (gives away organisational information such as generals down to foot soldiers and group size etc). Through to fingerprinting by the applications there are on the phone. Some apps such as ATAK can give away a lot of information.

In part it’s why certain governments are moving majorly forward to,

1, Client Side Scanning (via AI).
2, Full ID (via age verification).

Thus “full surveillance” of “known individual” for by far the majority of people.

This makes those “trying to stay below the radar” with a mobile phone “easy and obvious to spot” as they in effect “paint a target on their own back”.

Thus other non mobile phone / smart device needs to be used…

Some time ago now I was warning that “old school field craft” would have to be used for even minimal OpSec. With the new “issue” being mass surveillance is building a “virtual time machine”.

This means a lot of “old school field craft” either will not work or needs to be updated…

For instance a “dead drop” usually uses “flag signals”. These used to be things like “placed litter” or “chalk mark graffiti”. That are obvious if you know what you are looking for, but almost impossible if you don’t. Miniature CCTV now allows every thing there is to be seen to be recorded, thus correlated well after the fact as investigators “go over the tapes” over and over.

The “update” can be “double flagging” where you change the “flag signal” all the time, BUT you use another signal to “gate” it. That is to say if the flag signal should be ignored or not.

Obviously whilst a single flag is easy to correlate, a double flag with four states only one of which correlates is a lot lot harder for investigators. Add a third flag has eight states only one of which is valid. The flags can also be geographically well dispersed, or not physical but temporal in nature acting as a count down timer using intervals of days rather than seconds or minutes.