I need answer about this...

Main forum to discuss RTL-SDR related topics.
mlkn
Posts: 3
Joined: Tue Jan 10, 2017 10:47 pm

I need answer about this...

Post by mlkn » Tue Jan 10, 2017 11:02 pm

Hi all !

Please i want an answer about this question :

- If someone use a cheap RTL-SDR dongle and listen some private station in any software like Airspy etc... The owner of this station / emitting radio can know who is listen on him?

For example :mrgreen:

Person A talk with Person B in radio. And a Person "C" listen the conversation between Person A and B by this cheap rtl-sdr dongle! So the person A or B can know have someone listen to them?

Thanks in advance ;)

joe36
Posts: 36
Joined: Wed Jul 20, 2016 11:09 pm
Location: Cass co. in. 46994

Re: I need answer about this...

Post by joe36 » Wed Jan 11, 2017 12:32 am

No
Joe KA9UCN

DB Gain
Posts: 13
Joined: Tue Dec 20, 2016 8:20 pm

Re: I need answer about this...

Post by DB Gain » Wed Jan 11, 2017 5:20 pm

Here's what you need to do to be able to detect if someone has intercepted your signal;
https://arxiv.org/abs/1610.09434

AD5NL
Posts: 34
Joined: Fri Sep 16, 2016 7:00 pm

Re: I need answer about this...

Post by AD5NL » Wed Jan 11, 2017 9:38 pm

Well, obviously if you listen to your radio then you'll suck up all the RF and nobody else can hear him.

(just kidding!)

Pretty much the only way that a person would know that their signal has been intercepted is if you told them.

That is why ham radio operators invented QSL cards (a snailmail postcard confirming an on-air contact or that a listener heard the transmission).
Last edited by AD5NL on Wed Jan 11, 2017 9:42 pm, edited 1 time in total.

AD5NL
Posts: 34
Joined: Fri Sep 16, 2016 7:00 pm

Re: I need answer about this...

Post by AD5NL » Wed Jan 11, 2017 9:39 pm

One caveat -- if you are *extremely nearby* then the guy might see you / hear you / detect the weak signal from your radio's local oscillator.

mlkn
Posts: 3
Joined: Tue Jan 10, 2017 10:47 pm

Re: I need answer about this...

Post by mlkn » Fri Jan 13, 2017 10:50 pm

Thank you so much !! ;)

But can you explain me "technically" why the emitters cant know who listen to them?

I ask this because (sorry :oops: ) i see many public radio station says "We have XXX fans listen to us now" ! And even make stats to know how much peoples listen each radio station ! So how he can know that?

Thank you in advance !

rtlsdrblog
Site Admin
Posts: 2699
Joined: Mon Nov 19, 2012 11:54 pm

Re: I need answer about this...

Post by rtlsdrblog » Sat Jan 14, 2017 3:41 am

mlkn wrote:Thank you so much !! ;)

But can you explain me "technically" why the emitters cant know who listen to them?

I ask this because (sorry :oops: ) i see many public radio station says "We have XXX fans listen to us now" ! And even make stats to know how much peoples listen each radio station ! So how he can know that?

Thank you in advance !
Radio stations have no way to know the true number of listeners. They get those numbers by polling a number of users, and then extrapolating that to the population. They might also know from internet radio listeners. But not from RF.

mlkn
Posts: 3
Joined: Tue Jan 10, 2017 10:47 pm

Re: I need answer about this...

Post by mlkn » Sat Jan 14, 2017 6:48 pm

Thank you so much ! ;)

DB Gain
Posts: 13
Joined: Tue Dec 20, 2016 8:20 pm

Re: I need answer about this...

Post by DB Gain » Sat Jan 14, 2017 7:55 pm

In places like Merry Old England they have or had vans with sensitive electronics inside, that drive around listening for the telltale emissions of receivers, hoping to find those who haven't paid the tax on their receiver, so it (detecting receivers in use) can be done to a degree.
Most sdr receivers should be hard to detect that way as they don't have the multitude of oscillators oscillating away and leaking back through the front end of the radio to the antenna, unlike the typical heterodyne receiver, wich will have at least one fairly powerful oscillator running. The spooks have made efforts to reduce the emissions of their spook radios as described here;
https://en.wikipedia.org/wiki/Tempest_(codename)

KD7PTF
Posts: 4
Joined: Sun Jan 15, 2017 11:56 pm

Re: I need answer about this...

Post by KD7PTF » Mon Jan 16, 2017 3:02 am

Mlkn, YES Yes you caN be traced and even reversed listening now, With SDR the software now has the code in it so that the signals you listen to can now tell if you are listening and as well listen to you as long as the SDR unit is plugged in even if the PC is off. The developer's don't admit this as they have been hushed by the corporations that helped fund the software. So be careful, But of course they have already listened in on your SDR but for others be warned. Now the best thing you can do at this point Mlkn is to wrap the unit in saran wrap and then take some sort of thick based oil like peanut butter is perfect because it has the peanut oil in it be sure to stir the oil on top in but keep the oil wet in the part you use here. After you wrap in plastic coat it in peanut butter then another saran plastic wrapping, Be careful not squeeze the peanut butter out. The third wrap is now aluminum foil and that will do it. Now wrap very tight in duct tape silver is the best but camouflage is best. Desert golds are out. use the jungle greens or earth toned greens with browns. If you don't have the tape then you can still use old newspaper just use newspaper that is at least 6 weeks old.

Here is a small bit of info. I underlined the avoidence technice for you.

Secure communication and QKD.
Secure Communication: Suppose a sender, Alice, would like to send a secret message to a receiver, Bob, through
an open communication channel. Encryption is needed. If they share a common string of secret bits, called a key,
Alice can use her key to transform a plain-text into a cipher-text, which is unintelligible to Eve. In contrast, Bob,
with his key, can decrypt the cipher-text and recover the plain-text. In cryptography, the security of a crypto-system
should rely solely on the secrecy of the key. The question is: how to distribute a key securely? In conventional
cryptography, this is often done by trusted couriers. Unfortunately, in classical physics, couriers may be brided or
compromised without the users noticing it. This motivates the development of quantum key distribution (QKD).
Alice sends Bob a sequence of photons prepared in different polarisation states, which are chosen at random
from two conjugate bases. For each photon, Bob selects randomly one of the two conjugate bases and performs a
measurement. He records the outcome of his measurement and the basis choice. Through an authenticated channel,
Alice and Bob broadcast their measurement bases. They discard all polarisation data sent and received in different
bases and use the remaining data to generate a sifted key. To test for tampering they compute the quantum bit error
rate (QBER) of a randomly selected subset of data and verify that the QBER is below a certain threshold value. By
applying classical post-processing protocols such as error correction and privacy amplification, they generate a secure
key. This key can be used to make the communication
One-time-pad protocol: The message is represented by a binary string. The key is also a binary string of the
same length as the message. For encryption, a bitwise exclusive-OR (XOR) is performed between the corresponding
bits of the message and the key to generate a cipher-text. Decryption is done by performing a bitwise XOR between
the corresponding bits of the cipher-text and the key. For one-time-pad to be secure, the key should not be re-used.
chievements and future goals in QKD. On the
theory side, a landmark accomplishment has been rigorous
security proofs of QKD protocols. Recently, a
“composable” definition of the security of QKD
has been obtained.
Avoidance of detection. Use of plastic wrap in multiple stages and a thick plant based oil with isolation of wrapping then the cloth in duct tape is the best know blocker, Please see illustration for proper application.
Stable QKD over long distances (of
the order of 100km) has been achieved in both fibres
and free-spaceCommercial QKD systems are currently
available in the market. Field test demonstrations
of QKD networks have been done High detection
efficiency single-photon detectors at telecom wavelengths
have been developed In short, QKD

is already mature enough for real-life applications. As
an illustration, Fig. 1 shows the tremendous progress
that has been made in free-space QKD over the last two
decades. It compares the first lab demonstration performed
with two recent QKD implementations
that connect, respectively, two Canary Islands [8]
and a ground station with a hot-air balloon [22].
And, what researchers are aiming to do now? As will
be discussed in the rest of the paper, to guarantee unconditional security in actual QKD implementations, researchers
are working hard to bridge the gap between
theory and practice. Also, the development of high-speed
QKD systems, together with the ability of multiplexing
strong classical signals with weak quantum signals in the
same optical fibre, for example, via wavelength division
multiplexing (WDM), are major research challenges of
the field. Moreover, researchers are studying QKD network
set-ups with both trusted and untrusted nodes. The
feasibility of ground to satellite QKD has also attracted
a lot of research attention
Security model of QKD
Intuitively speaking, the security of QKD is measured
with respect to a perfect key distribution scheme where
Alice and Bob share a true random secret key. More
precisely, we say that a QKD system is -secure if and
only if the probability distribution of an outcome of any
measurement performed on the QKD scheme and the resulting
key deviates at most from the one of the perfect
key distribution protocol and the perfect key .
A typical value for is 10−10. However, in principle Alice
and Bob could select as small as they want, just by
applying enough privacy amplification.
Of course, since a secret key is a resource for other
cryptographic protocols (e.g., the one-time-pad method),
it is not enough to consider the security of the QKD
protocol alone. Instead, one has to evaluate the security
of the generated key when it is employed in a cryptosystem.
This notion is known as “composable” security.
Fortunately, QKD is composably secure That
is, if we have a set of cryptographic protocols (which may
include QKD), each of them having a security parameter

, as part of a certain cryptographic scheme, then the
security of the whole system is given by P

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