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Hiding Messages In VoIP Packets
Orome1 writes "A group of researchers from the Warsaw University of Technology have devised a relatively simple way of hiding information within VoIP packets exchanged during a phone conversation. The called the method TranSteg, and they have proved its effectiveness by creating a proof-of-concept implementation that allowed them to send 2.2MB (in each direction) during a 9-minute call. IP telephony allows users to make phone calls through data networks that use an IP protocol. The actual conversation consists of two audio streams, and the Real-Time Transport Protocol (RTP) is used to transport the voice data required for the communication to succeed. But, RTP can transport different kinds of data, and the TranSteg method takes advantage of this fact."
Deep Tone.
Steganography is tech which while I admire, I hope that I will never need to use. Sadly, the world seems to be going the other way.
its bits, electrical pulses, on and off 1 and 0, the gear does not give a shit what that represents just to shuffle it from point A to point B
You can avoid your messages being intercepted using this technique simply by piggybacking it on the one protocol that large telcos in every country are trying to find ways to block. Hooray!
OK, I'm being an ass. It's a cool concept.
You are not alone. This is not normal. None of this is normal.
From what I understand, steganography works if an observer (Carl) cannot tell that transmission of covert data is taking place between Alice and Bob. The proposed method results in an RTP bitstream that does not hold the payload advertised in its headers -- the audio is compressed using a more efficient codec than advertised in the packet headers, and the extra space is used to carry the "hidden" payload; Alice and Bob agree beforehand on the audio codec to use.
Now if Carl wants to eavesdrop on the conversation by hijacking (or owning) an intermediary network node, he would get corrupted audio data when trying to decode the packets with the (fake) advertised codec. Wouldn't this be a strong indication that covert communication is taking place?
I was thinking that a way of sending hidden messages between two locations (assuming a reasonably reliable network), one could introduce send messages by controlling the rate of the replies in a predictable manner (using ECC and varying transition timings for error rate compensation).
Another simple one would be with TCP/UDP in forcing out of order packets for positive/negative bit representation and similar correction routines as above.
Both hidden message systems are slow to send any substantial amount of information, but I can't see a reasonable approach to intercept without a full dump of the entire packets and timestamps which is more laborious than just the session data contents (assuming one is ManInTheMiddle). Further security on the payload as necessary, but the transmission of the message itself is hard detect.
Bye!
It's more likely you'll be the next victim in a car crash (unless you're living in a few specific parts of the world). "Subversive" doesn't necessarily equate to "terrorist", and not everyone that wants to hide their communications are dangerous to the public (or at all, necessarily).
It is pitch black. You are likely to be eaten by a grue.
If this is in the open, i.e. people are talking about it, every gov around the world will have or will soon have some rent a box to find this.
Your simple voip chat will glow in the dark and you will get a nice file opened or added to.
Domestic spying is now "Benign Information Gathering"
Most used codecs use some internal ECC, so filling RTP packets with your data will be easily recognized.
Another approach would be doing FFT on decoded audio. Codecs tend to produce wideband noise with random data and that is very different from usual speech frequency response.
Much better method would be using LSB bits in codec to transfer message. It would result in slight differences in pitch or other parameters, but it would be almost undetectable.
DECODE FAIL: According to my screen, your 2nd
There are plenty of ways that "subversive" groups can hide their networks from the authorities right now. Anyone can post encrypted messages to alt.anonymous.messages to hide the recipient, and anyone can use the remailers network to hide the sender. If you are curious about criminals doing this sort of thing, look up the "Yardbird" pedophile group, some of whom have continued to evade capture.
It is also worth mentioning that steganography is neither new nor undeveloped. Plenty of steganography tools exist right now and can be used by anyone. Anyone who runs an publicly accessible wiki has probably seen steganography on their wiki, in the form of inexplicable spam messages (my local LUG saw this). The movie industry routinely uses steganography in the form of watermarks that are embedded in movies, which identify the theater the movie was shown at.
Palm trees and 8
The terrorists' actions don't matter any more to you, since you obviously have already been terrorized and there's nothing more they need to do to you. Those who still have their self intact will continue on with progress.
You can do 56kbps AFSK (3.7 mbyte) and encrypt it yourself. Surprise! Someone rediscovered dialup.
for robbed-bit signalling back.
This is only noteworthy or nonobvious if you only have a basic understanding of computers. RTP allowed extension headers, and IPv4 does as well so you could embed extra data for almost any type of traffic on the Internet.
Many moons ago when phone calls were expensive, we used a system of rings to signal our parents to come pick us up at the movie theatres or whatever. For example, 3 rings, then hang up. Sometimes we used 3 rings followed by 2 or 3 rings if more information needed to be exchanged. This was a simple covert messaging system that didn't cost any money, so you could use a 'tickey box', without consuming a 'tickey'.
VoIP datagrams are intentionally small in the order of 10 - 20 bytes. VoIP uses UDP because it is a fast and efficient protocol. These datagrams are small so that if there is loss, there is minimal interruption of the real-time voice stream. You may hear nothing or a small blip. Adding overhead to the rtp stream by increasing the payload size defeats the quality of the voice transmission. The major concern of VoIP is sound quality, hiding data inside an rtp stream will do the opposite of exactly what the industry wants - the added payload will create poor audio quality. This just sounds like a bad idea (pun intended).
Stenography this is not.
Women have been hiding messages in voice streams in like forever.
Any time you see Alice and Bob are trying to communicate, you know they're up to no good. Every text book on security tells you so!
I was promised a flying car. Where is my flying car?
Out of order won't be very reliable, since there's no telling the Internet won't shuffle up your order a bit more.
I was promised a flying car. Where is my flying car?
My 2nd what? Don't leave us hanging!
Had they considered just recording it backwards?
Ummm.... This is what SIP was designed for, right? I mean, not really hiding, but passing messages along with a phone conversation?
But SIP aside, the other major VoIP protcol, H.323 allows for MISC messages of varing length with the packet as well. Oh, and if you are talking only about only encoding the message within the codec, G.722k allows for 4k per packet to be as "RESERVED, SPECIAL USE", which isn't apart of the voice stream.
And if they are talking about encoding messages in video, the MPEG standards which I believe are using allow for TEXT data withing the streams (or completely hidden streams all together).
Communicating via VoIP?! NO WAI!!
MacGyver Gets Lazy
Unity? Screw that: XFCE. Slashdot Beta? Screw that: SoylentNews. Australis? Screw that: Pale Moon. UX developers DIAF
This technique is used by ancient mobile switches to hide extra data in G.711 stream. Oh, good old TFO, RIP.
Are they embedding a protocol that checks packet sequence?
Thanks formfeed. I needed a giggle!
The camera moves over some dude's shoulder, so we can see the screen of his smartphone and his girlfriend at the same time. Girlfriend starts speaking. Smartphone provides real time translations.
You'll more likely be hit by lightning or killed by a meteor than killed by a terrorist (unless you are in an Arabic country).
Learn to love Alaska
Yes, it clearly isn't shorthand, but is it steganography?
Not sure if I'm a big fan of this although the work interesting. I can subversive groups using this proof-of-concept to implement communication networks hidden from the authorities. I could be the next victim in a terrorist attack so I have to refrain any enthusiasm in this regard.
People like you are responsible for the rapid erosion of our civil liberties. Try spending a little more time understanding statistics, probability, and security, and a little less time sounding like a cowardly fucking idiot.
Thank you, Edward Snowden.
"Arguments from authority are worthless." —Carl Sagan