tp@mccall.uucp (Terry Poot) (10/16/89)
I have no idea where to post this! There are gadgets one can put on a telephone that purport to tell you if the conversation is being recorded. Does anyone know if they work? -- Terry Poot (800)255-2762, in Kansas (913)776-3683 The McCall Pattern Company, 615 McCall Rd., Manhattan, KS 66502, USA UUCP: rutgers!ksuvax1!mccall!tp Internet: tp%mccall@ksuvax1.cis.ksu.edu
gregk@ubvax.UB.Com (Greg Kendall) (10/17/89)
In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: >I have no idea where to post this! > >There are gadgets one can put on a telephone that purport to tell you if >the conversation is being recorded. Does anyone know if they work? There was a long discusion of this point on another group a while back. The long and short of it was, NO, they don't work, because of day to day variations in tx lines, etc, etc.
henry@utzoo.uucp (Henry Spencer) (10/17/89)
In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: >There are gadgets one can put on a telephone that purport to tell you if >the conversation is being recorded. Does anyone know if they work? They can't; it's fundamentally impossible. Competently-installed recording devices leave absolutely no sign of their presence on the phone line, unless one is deliberately provided. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
johnl@esegue.segue.boston.ma.us (John R. Levine) (10/17/89)
In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: >There are gadgets one can put on a telephone that purport to tell you if >the conversation is being recorded. Does anyone know if they work? Of course not. I suppose they might be able to notice if someone hangs another phone on the line and picks it up and listens, but there are lots of ways to tap a phone that are not electrically detectable. For starters, the person at the other end might put the microphone of a recorder next to the earpiece. -- John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 864 9650 johnl@esegue.segue.boston.ma.us, {ima|lotus|spdcc}!esegue!johnl Massachusetts has over 100,000 unlicensed drivers. -The Globe
ee5391aa@hydra.unm.edu (Duke McMullan n5gax) (10/17/89)
In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: >There are gadgets one can put on a telephone that purport to tell you if >the conversation is being recorded. Does anyone know if they work? The answer is an absolutely definite maybe, with an appended probably not. First, "being recorded": There are ways -- of varying reliability -- to tell if your line has been tapped, but it'll require something on the order of deitic omniscience to tell you what's being done with that signal. Still, it's very likely that if you're tapped, you're being recorded. ECM -- governmentese for "electronic countermeasures" -- that apply to a tele- phone system fall into three categories: Prevention, detection and correction. Prevention (as usual) is the best, but what you asked about is detection. You can buy from various sources instruments purported to tell you if your line has an unauthorized tap on it. Do they work? Usually not. The methods vary. You can measure line impedance, which will detect low budget/ unsophisticated taps, you can listen for noise on the line, which is useless, or you can use TDM. That's technicalese for Time Domain Reflectometry. The idea is that you send a sharp pulse signal down the line, and watch carefully (i.e., with an expensive instrument) for reflections of the pulse which occur at every sufficiently abrupt impedance change in the line (i.e., at a tap). The TDM system also detects other telephones, connections to the service block, extension line connections, staples which penetrate the insulation, sharp kinks in the wire, etc. The TDM "signature" of the line is a pretty complex signal. This means that you must have the signature of a "clean" line, and compare this with your signatures as time goes on. When you spot a change, look into it. Is that reliable? Well...sort of. I've heard that you can tell from the location of a new blip in the signature where on the line the new impedance lump is located (which squares with my [sketchy] knowledge of TDM), but two other sources say that's a lot of bushwah in practice. It seems that you end up doing a physical inspection of the entire line anyway, which can be done without coughing up kilobucks for the TDM instrumentation and technician. For an authorized tap (done by the TelCo), forget detection. It's done at the central office (entirely in software, I'm told) and there exists no reasonable detection method from your end of the line. We should note that TDM methods usually involve breaking the line connection at the service entrance and terminating the block with the line's characteristic impedance, so you're not connected to TelCo when you do that test. That means that it isn't likely to tell you anything useful about a tap that's farther down the line than the telephone pole. Getting the signature of the connected line 1) may cause trouble with the TelCo circuitry and 2) changes anytime the TelCo techs do some line service, anythime the wind blows hard, and usually changes a bit when it rains. This applies to most detection methods: A simple bug is fairly easy to detect; a sophisticated one very difficult. The measures have a way of staying a step or two ahead of the countermeasures. Additionally, there's the cost factor. As expensive as GOOD bugging equipment is, the corresponding ECM stuff is a lot more expensive. Additionally, if I decided to tap your line, I don't waste money picking out lines at random: I just install the tap, sit back, listen, record, and prepare my blackmail info. On the other hand, you are in a worse position. Have I in fact bugged your line? You do a fairly simple (inexpensive) check. Nothing. Was your line bugged, or was it done in a way that you failed to detect? You spend more money and time. Still nothing, but you're still worried. Lotsa money later, you discover a fairly sophisticated radio transmitter, which you remove. There are no fingerprints, or anything else conclusive with which you can nail me. Still, everything's OK now, right? Right? Well...was that the only bug there? Was it placed for you to find, with another bug (which you haven't detected) backing it up? Did I place another bug after you found this one? Am I, in fact, the one who put it there? As you see, this sort of thing can lead directly to recursive paranoia. The bugger has advantage; the buggee the disadvantage. The only real safety is the preventative one: don't say anything on the telephone that you wish to remain private! Here's the best advice I've heard: If you're going to spend money on 'phone security, you're better off buying expertise than equipment. Pay your 'phone bill, d "In all levels of life, the sheep are only safe when the wolves are not hungry." -- F.J. Lovret Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu
illgen@hq.af.mil (Keneth..Illgen) (10/18/89)
In article <776@ariel.unm.edu> ee5391aa@hydra.unm.edu.UUCP (Duke McMullan n5gax) writes: >In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: >>There are gadgets one can put on a telephone that purport to tell you if >>the conversation is being recorded. Does anyone know if they work? > >The answer is an absolutely definite maybe, with an appended probably not. > >First, "being recorded": There are ways -- of varying reliability -- to tell >if your line has been tapped, but it'll require something on the order of >deitic omniscience to tell you what's being done with that signal. Still, it's >very likely that if you're tapped, you're being recorded. > >Prevention (as usual) is the best, but what you asked about is detection. You >can buy from various sources instruments purported to tell you if your line has >an unauthorized tap on it. Do they work? > >Usually not. > >The methods vary. You can measure line impedance, which will detect low budget/ >unsophisticated taps, you can listen for noise on the line, which is useless, >or you can use TDM. You mean TDR. TDM is Time Division Multiplexing and can't help you detect a phone tap. >That's technicalese for Time Domain Reflectometry. The idea is that you send a >sharp pulse signal down the line, and watch carefully (i.e., with an expensive >instrument) for reflections of the pulse which occur at every sufficiently >abrupt impedance change in the line (i.e., at a tap). The TDM system also >detects other telephones, connections to the service block, extension line >connections, staples which penetrate the insulation, sharp kinks in the wire, >etc. The TDM "signature" of the line is a pretty complex signal. This means >that you must have the signature of a "clean" line, and compare this with your >signatures as time goes on. When you spot a change, look into it. > >Is that reliable? Well...sort of. Actually it is very reliable provided you know the layout of the location you want tested. Testing in your home with a TDR would be a waste of time. It would take you less time to walk through the house to the junction box the it would to call Rent-A-Center to get a TDR. But if you know how the wires run in your office it can provide a clear indication of additional devices being attached to a line. >For an authorized tap (done by the TelCo), forget detection. It's done at the >central office (entirely in software, I'm told) and there exists no reasonable >detection method from your end of the line. This is true except that it's not entirely done by software. The software keys the line to be tested but the instrument that does the recording is put 'on-line' which will add to the impedance load. This (if you happened to be a a phone company technician in the building could be detected) used to be the little click you would hear. The click still happens only now it's a lot softer. >We should note that TDM methods usually involve breaking the line connection >at the service entrance and terminating the block with the line's >characteristic impedance, so you're not connected to TelCo when you do that >test. If you had the money and the paranoia you could simply tie in your TDR and your phone into a diplex plug and eliminate the first reflection on your scope by zeroing your meter after the pulse caused by your telephone/TDR. You don't have to disrupt the line to measure. This point could probably be debated regarding using and pulsing at the same time but my personal feeling is that the frequencies wouldn't interfere or bring down any equipment. >This applies to most detection methods: A simple bug is fairly easy to detect; >a sophisticated one very difficult. The measures have a way of staying a step >or two ahead of the countermeasures. >Additionally, there's the cost factor. As expensive as GOOD bugging equipment >is, the corresponding ECM stuff is a lot more expensive. Generally speaking cost can be pretty high however a reliable undetectable bug can be planted for around $100.00. It all comes down to where you plant it.
hollombe@ttidca.TTI.COM (The Polymath) (10/18/89)
In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: } }There are gadgets one can put on a telephone that purport to tell you if }the conversation is being recorded. Does anyone know if they work? Consumer Reports tested a bunch of these some time ago. None of them worked as claimed. -- The Polymath (aka: Jerry Hollombe, hollombe@ttidca.tti.com) Illegitimis non Citicorp(+)TTI Carborundum 3100 Ocean Park Blvd. (213) 452-9191, x2483 Santa Monica, CA 90405 {csun|philabs|psivax}!ttidca!hollombe
marks@whizbang.umiacs.umd.edu (Mark Schleifer) (10/19/89)
If a person who knows what they are doing puts a tap on your phone you won't be able to detect it. If you are willing to spend some money your best bet is to buy a scrambler. This will convert your message into a digital format which is almost impossible to decode. The only downside to this is that both parties must have them but they make any bugs on your line useless. You can even get portable scrablers that work with car phones. - Mark Spoken: Mark Schleifer Domain: marks@umiacs.umd.edu UUCP: uunet!mimsy!umiacs!marks Phone: +1-301-454-7678 USPS: UMIACS, Univ. of Maryland, College Park, MD 20742
carl@aoa.UUCP (Carl Witthoft) (10/24/89)
>In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: >}There are gadgets one can put on a telephone that purport to tell you if >}the conversation is being recorded. Does anyone know if they work? Naaaaah :=) I just got one of those yupscale catalogs at home. It has a phone monitor plug-in which will beep if the operator or someone on an extension phone picks up. The good part of the ad said "Warning. THis device will not detect the ultrsophisticated devices used by the CIA and KGB. If you are being monitored by one of these groups, you need a lot more help than this [gadget] can give you." well, true... -- Alix' Dad ( Carl Witthoft @ Adaptive Optics Associates) {harvard,ima}!bbn!aoa!carl 54 CambridgePark Drive, Cambridge,MA 02140 617-864-0201 "disclaimer? I'm not a doctor, but I do have a Master's Degree in Science!"
waters@darla.sps.mot.com (Strawberry Jammer) (10/24/89)
In article <20247@mimsy.umd.edu> marks@umiacs.umd.edu (Mark Schleifer) writes: } } If a person who knows what they are doing puts a tap on your phone you }won't be able to detect it. If you are willing to spend some money your best }bet is to buy a scrambler. This will convert your message into a digital }format which is almost impossible to decode. The only downside to this is }that both parties must have them but they make any bugs on your line useless. }You can even get portable scrablers that work with car phones. The only problem with scramblers are that they they don't work! The problem is that the actual number of codes is very limited (of course the dial may have 10M or more codes, but most of them are duplicates!). Audio scrambling using analog means is very easy to break as a result, digital scrambling can be made extremly difficult but requires 3-4X the bandwidth of the telephone line (2.5Khz Vs 16Khz). Not something you can use from your home or office. *Mike Waters AA4MW/7 waters@dover.sps.mot.com * He who attacks the fundamentals of the American broadcasting industry attacks democracy itself. -- William S. Paley, chairman of CBS
ted@nmsu.edu (Ted Dunning) (10/24/89)
In article <1917@dover.sps.mot.com> waters@darla.sps.mot.com (Strawberry Jammer) writes:
Audio scrambling using analog means is very easy to break as a
result, digital scrambling can be made extremly difficult but
requires 3-4X the bandwidth of the telephone line (2.5Khz Vs
16Khz). Not something you can use from your home or office.
this comment about bandwidth is inaccurate in these days of 9600 baud
modems. adaptive delta modulation can transmit very reasonable speech
over less than 9600 bits per second and encryption at this rate is not
difficult with dedicated hardware (and probably not out of reach for
something like a mips or sparc processor in software).
vocoder techniques can reduce the bit rate requirements to
approximately 2400 bits per second, but you tend to buy back the
sophistication of the modem with the sophistication of the coding for
the speech.
--
ted@nmsu.edu
Dem Dichter war so wohl daheime
In Schildas teurem Eichenhain!
Dort wob ich meine zarten Reime
Aus Veilchenduft und Mondenscheinjohnl@n3dmc.UU.NET (John Limpert) (10/24/89)
In article <1917@dover.sps.mot.com> waters@darla.sps.mot.com (Strawberry Jammer) writes: >Audio scrambling using analog means is very easy to break as a result, >digital scrambling can be made extremly difficult but requires 3-4X the >bandwidth of the telephone line (2.5Khz Vs 16Khz). Not something you can use >from your home or office. I know that there are NSA approved secure telephone systems for voice grade lines, I have seen ads in Aviation Week & Space Technology for the systems. Unfortunately, the NSA doesn't allow distribution of the technical manuals to ordinary civilians. Are there any low bit rate, commercially available voice encoder/decoder chips? I have seen variable slope delta modulation chips in unclassified, commercial equipment at 24/32 kbps. Decent audio quality but too fast for a normal voice grade line modem. The voice encoder/decoder seems to be the hardest part of a secure digital phone system. A relatively inexpensive system could be assembled with DES encryption and a V.32 modem. -- John A. Limpert I'm the NRA! Internet: johnl@n3dmc.UU.NET UUCP: uunet!n3dmc!johnl
gross@dg-rtp.dg.com (Gene Gross) (10/27/89)
In article <799@mccall.uucp> tp@mccall.uucp (Terry Poot) writes: > >There are gadgets one can put on a telephone that purport to tell you if >the conversation is being recorded. Does anyone know if they work? Terry, as far as I know they work. In fact, there is now a phone with such circuitry built-in. If you'd like more info on the phone, drop me an email note and I'll send you the ordering info. Peace, Gene
dangross@csd4.csd.uwm.edu (Daniel E Gross) (10/31/89)
I would never have believed they existed either, but in the new DAK (c) catalog they have a device that will either cut your phone off when another is picked up, or will cut off all other phones when you pick yours up. Could be useful if you're using an answering machine, or modem with call waiting respectively - I guess. There must therefore be some way to tell. I would think that the line voltage would be constant though after one phone was off-hook. Beats me? :-$ Dan Gross
donegan@stanton.UUCP (Steve Donegan) (10/31/89)
There is no such thing as security. If a dedicated person/government etc. wants to tap your house/phone/car/place of work etc. they can. No scrambler system sold on the market today is capable of stopping a government from snooping. The real question is - do you have something to hide that 'they' want to know about? For most people that answer would be no. Are you a simple law breaker - 'they' won't probably go to the effort to spy on you anyway. If you really do have something to hide then I hope you're using one-time codes and all the other goodies of spy technology if you want to stay 'free'. If you're a business person, concerned about your trade secrets, the best thing to do is only communicate in-person, via passed paper, which would be burned and flushed with all concerned present. Sorry, after working in security for a few years one does become a professional paranoiac. -- Steven P. Donegan, Area Telecommunications Engineer, Western Digital Corp. Western Digital is not responsible for my opinions. stanton!donegan || donegan@stanton.UUCP || donegan%stanton@UUCP