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How to Make a Secret Phone Call (2015)
- hnarn 7y agoIn 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?
- 4bpp 7y agoEven 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?)
- close04 7y agoPerhaps 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?
- gruez 7y agoIs approach is going to kill battery life because the phone has to be always online to receive those times transmission.
- ghostpepper 7y agoMost 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.
- pmoriarty 7y agoThe 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 https://en.wikipedia.org/wiki/Anonymous_remailer [2] - https://en.wikipedia.org/wiki/Traffic_analysis https://en.wikipedia.org/wiki/Traffic_analysis [3] - https://en.wikipedia.org/wiki/Mixminion https://en.wikipedia.org/wiki/Mixminion [4] - https://www.mixminion.net/minion-design.pdf https://www.mixminion.net/minion-design.pdf
- deugtniet 7y agoCorrect 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.
- hnarn 7y agoIf 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.
- upofadown 7y agoSignal runs off your phone number. So the problem would reduce to the one solved in the article at some level.
- jmg2 7y agoYou make your call on a phone that's on the local PD's imsi catching mitm? because that's what, would happen in London...
- tomcooks 7y ago> 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)
- IntricateJake 7y ago> CIA > illegal So just another day of work then?
- jt0 7y agoYes, 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 https://en.wikipedia.org/wiki/Extraordinary_rendition
- FDSGSG 7y agoIt 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.
- buckminster 7y ago"Kidnap" is even simpler.
- deleted 7y ago[deleted]
- StavrosK 7y agoKind of like saying "extraordinary procurement" instead of "theft".
- Pulletwee12549 7y agoI 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.
- Tuna-Fish 7y ago> 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.
- pg_is_a_butt 7y agoThat is the way you ensure Lester Freamon listening in on every call.
- lawlessquestion 7y agoFamily Dollar or any convenience store that sells cell phones and you should be good without an Id. (USA only)
- sammachin 7y agoJust use payphones
- cpach 7y agoThis comment prompted me to google. Apparently there are still 100000 pay phones still in operation in the US. In Sweden we have none left.
- Daniel_sk 7y agoI 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.
- jzwinck 7y agoIn 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.
- mlrtime 7y agoand urinals...
- chasd00 7y agoand 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.
- technothrasher 7y agoIn 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.)
- amelius 7y agoSpeaking of which, what is the best way to create a throwaway email account?