How to Make a Secret Phone Call (2015) | Hacker News Reader

How to Make a Secret Phone Call (2015)

fastcompany.com

I think there is confusion between some of the terms he is using. I don't believe this is a secret call so much as one where the parties are unidentified. The contents of the phone can be trapped, and if there is any exchange of identifying information, an investigation can be successful.

With burners at the 7-11 they seem to want buyer information, even with cash. I have yet to find an untraceable burner.

> With burners at the 7-11 they seem to want buyer information, even with cash. I have yet to find an untraceable burner.

The way you get an untraceable burner is find the closest junkie, and pay him extra to go purchase you a phone.

In the current year, I guess the answer is simply "use Signal". I'm not sure I understand why it's so important that it has to be an actual phone call, even for a thought experiment, i.e. it has to go over the phone network to a device with a phone number. If that is the case in any real scenario, it seems a reasonable guess that it's because one or two parties are somehow restricted from using other channels -- and if so, is there any reason to believe that this restriction would not in itself make it simpler to monitor that restricted party, and therefore less secure?

Even if Signal's assertion that they do not keep metadata is in fact trustworthy, a network-scale adversary (such as a nation-state) could easily figure out that you called someone and who you called by looking at the data exchanged between your phone (which they know) and the Signal servers, and looking what other connections started and ended at the same time as yours and had a similar bandwidth usage profile.

(How many Signal phone calls are even started in any given short window of time, like 1 second?)

Correct me if I'm wrong, but I believe the signal servers are hosted on google cloud, using encrypted traffic to obfuscate the point of exit for a signal user.

This is why in the past, governments were unable to block signal without blocking google or all google cloud customers themselves.

Perhaps this would be another way to obfuscate the collection of metadata with techniques similar to anti-fingerprinting in Tor. An app like Signal could sync the time across all parties and send/receive all data in predetermined packet sizes and at predetermined delivery times across vast enough segments of their network. This would in theory make it a lot harder to infer who are the partners in a specific conversation based on timestamps and traffic volume.

The mechanism for picking the interval and packet size is debatable as long as the entropy of these values is low enough (does not allow for uniquely identifiable values). Maybe randomly from a list of predetermined values, taking into account some priority you set in advance, the size of the message, or the network conditions.

If every client/server on the network sent and received the data in synced identically looking bursts it might raise the bar for successful metadata analysis. Any chance Signal or any other app already do this?

The techniques you're talking about, and others, have also been used in anonymous remailers[1] to resist traffic analysis[2].

The mixminion[3] remailer design document[4] goes in to details on those mitigations.

Of course, real time conversations require certain constraints that email messages don't have, so some of the mitigations techniques used in remailers might not be practical here.

Signal's designers must have been well aware of Tor and anonymous remailers, so if traffic analysis mitigation techniques were not used by Signal it was a deliberate design decision on their part.

[1] - https://en.wikipedia.org/wiki/Anonymous_remailer

[2] - https://en.wikipedia.org/wiki/Traffic_analysis

[3] - https://en.wikipedia.org/wiki/Mixminion

[4] - https://www.mixminion.net/minion-design.pdf

Is approach is going to kill battery life because the phone has to be always online to receive those times transmission.

Most modern CPUs/SoCs spend most of their time (ideally) asleep or trying to go to sleep, and then waking at predefined intervals to transmit data. As long as this interval could be synchronized to some multiple of the transmission interval I don't think this would negatively impact battery life.

If they know about your physical device you are in a bad situation, but you would be in a worse situation if you used a phone line that they knew about. If we're moving the goal posts then yes, there are many ways to compromise a connection, but in no situation can I see that it would be beneficial to use a landline or a regular cellphone over a smartphone with the ability to encrypt and authenticate. So why is the question how to "make a secret phone call" if a phone call is an inferior technology to begin with? If the threshold for usage was high and required specialized technical knowledge, then sure, but you can hardly say that about Signal or VPN applications.

Signal runs off your phone number. So the problem would reduce to the one solved in the article at some level.

Speaking of which, what is the best way to create a throwaway email account?

Tor browser and the email provider of your choice. I find that cock.li makes it particularly easy to create new accounts and does not restrict Tor use.

10minutemail.net

Just use payphones

"Am heutigen Donnerstag, 28. November, wurde in Baden die letzte Schweizer Telefonkabine abmontiert."

Translates to "Today Thursday November 28 (2019) the last payphone in Switzerland was disconnected."

The cool thing with these payphones was that they had their own publicly available number so you could call them. Something I had not seen in other countries.

Source: https://www.nzz.ch/panorama/kein-anschluss-unter-dieser-numm...

way back in the day, it use to be a thing to hang out at payphones. your friends could call you there.

This comment prompted me to google. Apparently there are still 100000 pay phones still in operation in the US. In Sweden we have none left.

I was surprised there are so many of them in US, at least when I was in California. But that's also probably because there was little or no cell phone coverage outside of the cities where we went. Most countries in EU have an almost complete cell network coverage including remote areas.

In cities such as New York the payphones are not really used for placing calls. Their primary function is as a substrate for advertising. No amount of money can buy ad space in some of the best payphone locations.

In New York, most of the pay phones have been replaced with "LinkNYC" kiosks, which provide free WiFi, charging, tourist info, and yes... actual phone calls.

(As well as still providing advertising space. Always with the advertising.)

In other words, they provide basecamps for panhandlers.

Installations up and down 7th Ave or Broadway, for instance, are typically abutted by a kind of cardboard picnic blanket spread, covered with makeshift bags of belongings along with the pan handler’s signage and pan.

The mendicant roosts there with tablet and phone plugged in for juice, watching YouTube played over the WiFi.

Some stores have taken to piling the day’s trash bags around the base instead, before someone posts up.

I’m curious who thought these wouldn’t turn out co-opted by panhandlers camping or as a pole to pile refuse around — I’m not sure which setup is a less appetizing context for advertising!

and urinals...

and for drunks to beat on. There use to be a handful in an art/music neighborhood here in Dallas (Deep Ellum) and they were always bent and beat to hell.

"Remote" means something very different in West Texas, Montana, and many other places in the U.S. than it does basically anywhere in Europe.

> The CIA’s faulty cell phone tradecraft used in the 2005 extraordinary rendition of Hassan Mustafa Osama in Italy

With "extraordinary" I hope the author means illegal (the 23 CIA operatives cowardly fled Italy to avoid being incarcerated)

Yes, this is what is meant. Specifically: "Extraordinary rendition, also called irregular rendition or forced rendition, is the government-sponsored abduction and extrajudicial transfer of a person from one country to another with the purpose of circumventing the former country's laws on interrogation, detention and torture. Such renditions have been carried out (for example) by the United States government."

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

It would be much more honest to just use "unlawful rendition" as opposed to the terminology coined by the US government in order to make their illegal actions seem more palatable.

"Kidnap" is even simpler.

Kind of like saying "extraordinary procurement" instead of "theft".

They call that civil forfeiture.

The British Empire prefers the more neutral "acquisition."

It was the least untruthful thing he could say.

Plus it sounds like someone played Hamlet extremely well.

"You should have seen that rendition... It was... extraordinary."

> CIA > illegal

So just another day of work then?

Reply on news.ycombinator.com