Encrypting BitTorrent to take out traffic shapers
Written by Ernesto on February 05, 2006Over the past months more BitTorrent users noticed that their ISP is killing all BitTorrent traffic . ISP’s like Rogers are using bit-shaping applications to throttle the traffic that is generated by BitTorrent.
But, at the same time two of the most popular BitTorrent clients are working together to implement header and message stream encryption in order to take out these traffic shapers.
Currently both Azureus and uTorrent included this new form of encryption (specs) in their latest Beta’s. The fact that these two clients are actively working together to implement this new feature is promising and will make this form of encryption the new standard since the users of these two clients cover the majority of all BitTorrent users.
There are two “encryption modes” available.
The 2 different payload encryption methods plaintext transmission and RC4 provide a different degree of protocol obfuscation, security and speed. Where the plaintext mode only provides basic anti-shaping obscurity, no security and low CPU usage the RC4 encryption obfuscates the entire stream and not only the header and adds some cryptographic security at the price of spent CPU cycles.
The question now is.. Does it work? and how effective is it? If it works it will definitely offer a great solution to all BitTorrent users who suffer from traffic shaping ISP’s.
Bram Cohen, the creator of the BitTorrent protocol reacted quite negatively on these new developments. He questions the need for encryption since only a few ISP’s are actively shaping traffic. Among other things he also fears incompatibility between clients and increased cpu usage. Although these arguments can be countered quite easily, developers should keep them in mind.
But the fact is, if this new encryption method is launched successfully it will be a huge step forward for the BitTorrent community.
Previously: Speed up your torrents II
Next: Opera integrates BitTorrent in their Browser


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I have had the feeling that more and more ISPs are choking torrent traffic. way to go, this will help people who widely use torrents
i recently migrated from tiscali to pipex without realising that pipex throttle torrent speeds! couldn’t reach above 30(max) KB/s.
However,i sent pipex a not so nice email asking for my MAC code(only a day after joining them) and i also started using utorrent(with encryption enabled) and now my download speeds are maxing out at 240 KB/s..Not sure wether it was the email or utorrent that worked but hey-who cares! :)
@ C-Man
Fine point regards DNS lookup. This contention happens frequently on my ISP, a UK company that was early (for this market) to rolling out 8Mbps and even 16Mbps service. DNS frequently crawls, stalls, hiccups, basically times out often mid - session in an important transaction.
Dare i say it, the backhaul is run by Cable and Wireless. I didn’t realise this, but i have direct experience of C&W NOC staff, and they’re short a clue or two.
Explaining “network conditions” to home users is far from funny. I can deal with it because i can cache DNS at my router, which makes life a little easier. Yeah, typical Joe Six-Pack trick that :-)
Whilst i heartily dislike the advertising standards - or lack of them - in the ISP game, traffic shaping could be more aggressive for the BENEFIT OF USERS.
The ISP i mention a week ago sent me a ‘mail saying “no more residential customers”, then apparently retracted that letter. I think i can guess the troubles that lead to their wavering. Business customers have real incentive to fix their traffic at source. I think however my ISP was being rather hopeful.
In an ideal world, i’d shape at my border, and the uplink would be wide open. But then everyone had better be doing the same . .
The ISP owner above who MANUALLY shapes his traffic i think is totally nuts. Intervening personally is guaranteed to create unpleasant issues with customers. Quite apart from the waste of his/her valuable time, the personal intervention will always come across badly. Furthermore, the case cited above does not take account of users need to grab increasingly large patches or other files which are nothing to do with leeching, filesharing, bittorrent or commons abuse. Just think of dealing with Windows Update on a older RTM install - that’s one heck of a lot of patches to get that box configured, and that’s a very common situation for home users i meet.
just some idle observations . .
To the ISP cry-babys:
What you are doing has got nothing to do with “buying a Corvette and getting stopped for speeding”
What you are doing is more like an Airline selling more tickets than there are seats on the plane.This is shifting the burden to the customer. Its NOT the customers problem that you want to sell something (bandwith) that you dont actualy have. I have a contract with my ISP (like do most of us).In this contract it is agreed that my ISP sells me 6/6 Mbit UNLIMITED bandwith and that I pay a fee for this. Thats contract-law 101.If you have say 100 customers with a CONTRACT like that its YOUR job to make shure you can fullfill the agreed terms.
If you dont HAVE 600Mbit then DONT SELL IT!!
I wonder if the busts against BitTorrent
has anything to do with encryption?
can you imagine the growth in encrypted traffic since this started? Im shure the NSA is working more than overtime decrypting all that “terrorist” traffic!!
I am using azureus and noticed that when i download my connection speed for surfing drops from around 8-9mb to 300kb ! I am on the Telewest network and when turning on the plain encrip everything returned to normal, it very annoying that isp’s do this if I pay for 10mb then i should be able to run what ever i like across the link providing its legal!!
for 4 months our isp has been throttling bt traffic and i moved to usenet
this afternoon i was bored and went through google and encrypting bt traffic and found a few sites - it took me 2 minutes to enable the necessary options in utorrent and am currently now using bt again
(i have admin access to our network and know that we are actively traffic shaping)
my dilemma now is whether i say anything ;) or if there is anything we can do
Traffic shaping sucks… Rogers up here in Canada has started with some new high tech shaping junk. But protocol encryption does work. The fact that Bram reacted negatively suprises me as more and more isps begin to throttle etc..
i am in a college that blocks/monitors for bitorrent traffic what are the best settings for me in utorrent? please someone email me at benknefelkamp@gmail.com
i think the biggest problem with piracy today is people (mostly kids, no offence) think they have some right to actually do it. they think that if its free its for me.. they dont understand how this all started. think about where the stuff comes from. the source of a pirated release has to do something illegal in order to obtain a release. sadly the motivation for this is mostly money. the fact that it trickles down to the internet has nothing to do with a 16-year old kid in his parents basement downloading movies all night. the bottom line is someone has always had to pay the price for the data that is being pirated. back in the old days someone had to pay for the bbs server. now people want the ISPs to pay for it (by using their BW). If they stopped and thought about it, do you think rogers or whoever really wants to pickup the tab? You honestly cant blame the ISP for wanting to protect their investment. there will never again be a REAL decentralized form of filesharing (i think that died with BBS, who else knew what you were doing besides the server admin, the phone company? lol) now that everything goes through the internet, we are all connected, so its all centralized in one way or another. Ofcourse technology will advance and there will always be ways around it, but people who complain about having to learn about something in order to get their movies is stupid. you arent paying for the copyrighted work you are downloading, so who cares if you have to check a few boxes in your torrent program? if its that big of a deal to you, disconnect your interent and now you have a extra 40$/m to spend on dvds. I dont blame the ISPs for taking a proactive approach to stopping the abuseof their pipes, they run a buisness and want everyone to be happy, not just people who are downloading things ILLEGALLY.
Now are far as ISPs are concerned, if more ISPs start throlling or shaping or controlling BW usage in some shape or form, the regular home users arent going to notice, and these kids who leech off their parents internets are gonna have to stop pirating movies, simple as that. Eventually there will be a blacklist of ISPs who dont throttle, and who do you think the MPAA and RIAA are gonna look for first?
bittorrent is still a bottom feeder as far as pirated material goes. there will always be better, faster, more secure ways for people who work for the material they get (and derserve it, imo). I am totally against 1-click piracy is any form. I goes against everything ive learned about internet file trading. Thats why the ammount and quality of releases has gone down in the past few years, because now anyone can do it, it actually IS a problem now. If you have 5 drug-dealers in your town of 100,000 people, does your town have a drug problem? no, 90% of people prolly dont even know there are drugs in town. now invite 1000 more drug dealers into your town, do you have a drug problem now, do you think people realize it? in my understanding of the internet, piracy started for those 5 people who contributed in some way, and prolly sold what they got and made money (which i am against). now those 5 people are SOL and are less likely to contribute, hurting the now uncounted piraters as well as people who have nothing to do with piracy.
the bottom line is.. how can you complain about how difficult it is to get something you shouldent have? its not that ISPs that should addapt to yuor habits, but you that have to addapt to the habits you have already.
(i dont want any posts on how my spelling or grammar sucks :) )
[quote comment="498"]BitTorrent is far too reliant on specific ports and far too reliant on those ports being open inbound. Because of this, it is ridiculously simple to block BitTorrent traffic.quote]
Maybe, apart from the fact that bittorrent clients can change port however many times you’d like.
Hence surely you can never block bittorrent specifically without blocking pretty much everything else.
[anyone still use port 6881? Don't!]
Well, just wanted to drop a note that the packet encryption that bittorrent programs use have failed where I come from.
If it’s a war thats happening, then the ISPs have an advantage for now. Many advanced traffic shaping programs can easily throttle even encrypted torrent traffic.
I agree with derboxen that it IS our bad habits that are making us scream most in frustration - i suspect the most outspoken complainers are those who spend almost all their connected time downloading 9gig movies.
However, I have read the earlier posts and I do agree on a lot of other points as well.
1. ISPs should NOT be basing all of their marketing and advertising campaigns on their superior speeds, price/speed ratios, movie music content, etc when they can’t deliver the moment a new protocol emerges that tests their limits. Let alone those ISPs that shout “Unlimited Usage” on their banners, have pictures of corvettes/speedometers on their leaflets, or of people downloading movies on their TVads. They’re lying to their customers - flat out and simple. I know - because I feel cheated.
2. Even though at the moment p2p programs are predominantly used for piracy more than anything else, I can only imagine the horde of other legal uses it can be used for - and killing a well designed protocol is in no way helping advance the technological level of the Internet in any way. It is these things that have helped shaped the Internet into what it is today, that have actually increased the very reason why we need broadband from dialup, why the Internet is no longer just for emails and simple websites. I would love to imagine a not so distant future where everyone is interconnected 24/7 wherever they are and able to access terabytes of SHARED information at a thought. Furthermore, I would love to see the day when LEGAL movies and music are shared over protocols like torrent - with a fee of course - but no different from cable TV broadcasts. Throttling torrent traffic right now just smells of severe resistance to change by people with only short term money making goals on their mind.
3. Business model wise, it’s understandable why ISPs are forced into doing what they’re doing now. But there ARE other choices and other ways they could have done it. Who’s to say that in attempting to please the 90% of customers that do not use filesharing programs - that some of these 90% of customers WILL eventually come around to learning how to fileshare - and end up getting pissed at their service provider? Are the ISPs going to end up neglecting them as well when the time comes? Do the ISPs honestly believe that the upcoming generation of users will be content paying a monthly fee just to sit at home and check their mails? How exactly do they think their business model will survive in the next 10 years if they do this? Do they know that some forms of traffic shaping may not only impacts filesharing programs - but also some types of online gaming built around similar concepts? What if revolutionary sites like youtube’s video sharing and flickr’s photo sharing idealogy decide to jump on the filesharing bandwagon - which is a wonderful idea in my opinion - Will they get snubbed too?
I would not like to discuss what metaphor best describes this situation. The truth of the matter is, ISPs have no right to keep their users in the dark of whatever changes they are doing - especially changes that have a strong negative impact on a group of paying customers. Even more so, ISPs must have the responsibility to inform all prospective customers of the limitations in their systems (that they cant use p2p programs for example). To do so otherwise is just asking to be facing a major lawsuit eventually. And believe me, had I the money to sue, I would. I WAS cheated afterall.
[quote comment="498"]Completely worthless. I’m extremely disappointed that people who know enough to develop BitTorrent clients don’t know enough about networking to realize that this is completely pointless. Sure, encrypting the stream may get around a few packet shapers, at the moment but, unless they reconfigure BitTorrent to run everything, incoming and outgoing, over port 80 or 443 then it will be trivial to block BitTorrent.
BitTorrent is far too reliant on specific ports and far too reliant on those ports being open inbound. Because of this, it is ridiculously simple to block BitTorrent traffic. Encrypting the stream will not hide the fact that it is BitTorrent traffic. It will only prevent someone from identifying what the BitTorrent traffic is transferring. This may be a good thing for pirates but, it won’t stop the network administrator from blocking BitTorrent ports completely.
The truly successful P2P app will allow multiplexed up/downloads over SSL port 443. This will be encrypted and will appear like most other https applications. It will also traverse most any firewall and be stupidly simple for the user to operate. The down side is that it would require a centralized server to make it work so, it isn’t desireable for piracy but, I think this is also a good thing. I’m sure you’ll disagree with me on this one though because you no doubt feel that “sharing” music is your God given right and is not stealing or piracy.
Bram Cohen’s BitTorrent is doomed because it doesn’t work as well as it should (multiplexed downloads should perform far better than BitTorrent), it relies too heavily on opening obscure inbound ports, it is too hard for the average AOLer to get working, it is too easy to block.[/quote]
Sigh.. you know guys.. its not really about how easy it is to block bittorrent traffic etc..
The REAL issue here is bandwidth consumption for p2p filesharing. ISPs should realize that they are building a busines model on a rapidly advancing technology - and that they should be prepared to make hard investments on their infrastructure when it is required - rather than going the short route and giving their customers the middle finger.
It doesn’t really matter whether its torrents or some more advanced protocol that emerges later on, its just simply unethical to throttle speeds in any way.
Well, if a provider throttles P2P traffic, it means that it sells you bad service. You don’t get for you money what you want. So what you can do (besides encryption):
1. Switch to another provider which will sell good internet (without shaping). Maybe it will cost more (naturally), but you will get better service.
2. Publicize information about your provider, so all prospective customers would know which providers do throttle and which doesn’t.
@ISP_Bob
This comment was a while back, but it pissed me off, so I wanted to reply.
Bob, I have the right to use the bandwidth because that is the service as it was advertised to me. I pay $38.95 per month for 60 GB throughput, at 5Mbps down, 512kbps up. Nowhere is it stated that some protocols will get severely reduced (near zero) speeds. If my ISP cannot provide this to me, they should change their package to a profitable one.
On a side not, before I downloaded Azureus, thanks to this article, I was actually using more bandwidth downloading painfully slow torrents, as my up speeds were faster than down, and while I normally stop the torrent when my ratio hits one, I was instead maintaining a ratio around 3.
Well Mr. Bram Cohen is a bit clueless, if you live in a small town with one or two ISPs then your choices are limited, you can’t just cancle your account and go with a new ISP.
I heard that they, (The ISP’s), are planning to throttle down all packets that are unknown to them. Thus rendering packet encryption useless. It’s coming soon. The free lunch will soon be over.
If you are looking for speed, Newsgroups are the best way to go.
It’s called a fair use policy or acceptable use policy. Most ISP’s have them, this is disclosed to you when you purchase service, you just need to read the agreements your parents signed for you. Now some ISP’s will be vague in saying what is throttled.
There’s also the piracy concern. With the recording industries cracking down on P2P networks and subpoenaing abusers ISP’s have to make a descion on how to treat that type of traffic. Since we all know you guys are downloading your favorite porn movies, music, and videos why not throttle this traffic to make room for legitimate requests.
You are NOT paying for a 6mbps/512kbps (down/up). All broadband ISP’s I’ve ever had any interaction with provide UP TO, those famous two words. You get UP TO 6mbps/512kbps, you may get slower depending numerous variables and by abusing the acceptable use / fair use policy. An unlimited connection @ 5mbps synchronous from an ILEC/CLEC will normally run you a couple grand, about half of that is for local loop fees.
ISP’s are a business and profit from reselling bandwidth. Most smaller ISP’s oversell their pipes, because very rarely will they have their entire user base trying to download the paris hilton sex tape all at once. It does happen, and this is when congestion occurs. If the ISP is smart they use a bandwidth manager that implements certain bandwidth policies for users and protocols on the network to bring the equilibrium back to the network. That way users connections don’t time out, they just simply slow down until the congestion passes.
In sort your 39.99/month is peanuts, you’re not guaranteed anything and the ISP has total control of what protocols they decide to run on the network. You should be greatful the connection you do have and quit your bitching. :)
Or just buy through an ILEC if you’re fortunate enough to be in their access areas. They have the most bandwidth and usually don’t throttle anything.
[quote comment="498"]Completely worthless. I’m extremely disappointed that people who know enough to develop BitTorrent clients don’t know enough about networking to realize that this is completely pointless. Sure, encrypting the stream may get around a few packet shapers, at the moment but, unless they reconfigure BitTorrent to run everything, incoming and outgoing, over port 80 or 443 then it will be trivial to block BitTorrent.
BitTorrent is far too reliant on specific ports and far too reliant on those ports being open inbound. Because of this, it is ridiculously simple to block BitTorrent traffic. Encrypting the stream will not hide the fact that it is BitTorrent traffic. It will only prevent someone from identifying what the BitTorrent traffic is transferring. This may be a good thing for pirates but, it won’t stop the network administrator from blocking BitTorrent ports completely.
The truly successful P2P app will allow multiplexed up/downloads over SSL port 443. This will be encrypted and will appear like most other https applications. It will also traverse most any firewall and be stupidly simple for the user to operate. The down side is that it would require a centralized server to make it work so, it isn’t desireable for piracy but, I think this is also a good thing. I’m sure you’ll disagree with me on this one though because you no doubt feel that “sharing” music is your God given right and is not stealing or piracy.
Bram Cohen’s BitTorrent is doomed because it doesn’t work as well as it should (multiplexed downloads should perform far better than BitTorrent), it relies too heavily on opening obscure inbound ports, it is too hard for the average AOLer to get working, it is too easy to block.[/quote]
You can Have bit-torrent run on any port it is just like web servers running of your home pc if your isp doesnt allow it to run on 80 then run it on 8080. I am in favor of this encryption, I am using it now have noticed no speed decreases and very little cpu increase. I dont like how the RIAA and MPAA act like they can just sniff anyones network traffic and get away with it. I hope that Torrentspy and whatever other site is in a lawsuit wins and tells those stupid pricks that they are in fact breaking the law and all their practices are unconstitutional.
“I’m extremely disappointed that people who know enough to develop BitTorrent clients don’t know enough about networking to realize that this is completely pointless.
BitTorrent is far too reliant on specific ports and far too reliant on those ports being open inbound.”
- George W
Clearly you have never used BitTorrent before.
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