# Cell-Phone Conversations: Private or Not? **URL:** \ **Category:** Factual Questions\ **Created:** [July 28, 2002, 12:56am UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183 "2002-07-28T00:56:58Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Quasimodem](https://avatars.discourse-cdn.com/v4/letter/q/e274bd/32.png) [@Quasimodem](https://boards.straightdope.com/u/Quasimodem)\ **Post date:** [July 28, 2002, 12:56am UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/1 "2002-07-28T00:56:58Z")
So, can people listen in on my cell-phone by using a scanner or not? Thanks Quasi ---
**Author:** ![I\_forgot\_my\_username](https://avatars.discourse-cdn.com/v4/letter/i/ecd19e/32.png) [@I\_forgot\_my\_username](https://boards.straightdope.com/u/I_forgot_my_username)\ **Post date:** [July 28, 2002, 1:00am UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/2 "2002-07-28T01:00:52Z")
If they had the right equipment it COULD be possible to listen to a cell phone conversation. ---
**Author:** ![Mr.Blue\_Sky](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Mr.Blue\_Sky](https://boards.straightdope.com/u/Mr.Blue_Sky)\ **Post date:** [July 28, 2002, 1:01am UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/3 "2002-07-28T01:01:00Z")
The newer digital cell phones are extremely difficult to eavesdrop on. At one time, a certain electronics chain sold a scanner that could pick up older cell phone frequencies. The scanners were later modified to prevent this. Many of the un-modified scanners still exist, so it IS possible. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [July 28, 2002, 4:28am UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/4 "2002-07-28T04:28:32Z")
It’s easily done. Scanner modifications to do this are illegal but technically trivial. Anytime you are communicating on any wireless device you should be under the assumption that someone could be listening. ---
**Author:** ![Ms2001](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ms2001/32/18463_2.png) [@Ms2001](https://boards.straightdope.com/u/Ms2001)\ **Post date:** [July 28, 2002, 8:05am UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/5 "2002-07-28T08:05:34Z")
An analog scanner won’t pick up digital cell phone transmissions. The transmissions are encrypted (possibly controlled by a setting on your phone), so I wouldn’t be too worried about casual eavesdropping with a digital scanner either. If someone _really_ wants to hear your conversations, they might be able to decrypt them, but probably not in real time… and if the government wanted to listen in, they’d just place a wiretap at your cellular provider’s end. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [July 28, 2002, 4:31pm UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/6 "2002-07-28T16:31:46Z")
> [@](#): > > \*Originally posted by astro \* > \*\*It’s easily done. Scanner modifications to do this are illegal but technically trivial. Anytime you are communicating on any wireless device you should be under the assumption that someone could be listening. \*\* Digital cell phones technology that very difficult to listen in on for a variety of reasons. The scanners that astro is talking about are basically a radio that you can tune the carrier frequency into the range that analog cell phones operate at. To listen into a digital cell phone conversation is not technically trivial complex software running on probably specially developed hardware would need to be developed. > [@](#): > > \*Originally posted by Mr2001 \* > \*\*An analog scanner won’t pick up digital cell phone transmissions. The transmissions are encrypted (possibly controlled by a setting on your phone), so I wouldn’t be too worried about casual eavesdropping with a digital scanner either. > > If someone _really_ wants to hear your conversations, they might be able to decrypt them, but probably not in real time… and if the government wanted to listen in, they’d just place a wiretap at your cellular provider’s end. \*\* Digital phones conversations are not encrypted. The exchange of information about what phone is making the call are encrypted to prevent cloning of phones. The actually phone conversation is not encrypted. I worked very peripherally on a project that was to design a cell phone for the government that would encrypt conversations. I don’t know if this every got beyond the demonstration stage. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [July 28, 2002, 5:02pm UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/7 "2002-07-28T17:02:22Z")
It appears I was wrong. GSM does encrypt the phone calls. The encryption however has been broken. [http://www.wapsight.com/info/1999/12/07/000003.html](http://www.wapsight.com/info/1999/12/07/000003.html) [http://www.usatoday.com/life/cyber/tech/ctg848.htm](http://www.usatoday.com/life/cyber/tech/ctg848.htm) This one implies that CDMA has encryption for the conversations but they are mistaking complexity for encryption. [http://www.mobilecomms-technology.com/projects/cdma\_is95/](http://www.mobilecomms-technology.com/projects/cdma_is95/) An article directly pertaining to the Original question. And basically says it is an expensive proposition to eves drop on a digital cellphone call. [http://www.siliconvalley.com/mld/siliconvalley/3411134.htm](http://www.siliconvalley.com/mld/siliconvalley/3411134.htm) ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [July 28, 2002, 8:08pm UTC](https://boards.straightdope.com/t/cell-phone-conversations-private-or-not/121183/8 "2002-07-28T20:08:55Z")
To listen to snippets of analog phone conversations is remarkably low tech. Oldish analog phones can be easily programmed to passively listen to any given cell phone frequency. The local Goodwill sells these for a couple $. Note that if the target is moving, they keep being switched over to new towers and frequencies. Supposedly, these phones can also be setup to track the phone call thru such moves, but I have my doubts. Unlike scanners, you have to keep manually punching in frequencies (and there’s a lot of them) until you hear something you like. Some of the analog cell spectrum also is in the upper part of the old UHF TV spectrum (above ch. 69). Older TVs that can be tuned to these frequencies can also pick up cell phone conversations. I had such a TV until recently but no more. I’ve always assumed that 99.9999% of cell phone conversations are banal and I doubt that no matter how hard I tried I would ever hear anything remotely interesting. I’ve got better things to do with my time. Analog or digital, though, you should assume that you calls are being heard by others.