Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
I hear that. But I don't see why mainstream wallets and wallets designed for crypto research should not share a common core. I think there was some misunderstanding. I was saying they *could and should* share common cores, so we are in agreement without realising it :) I also didn't mean to imply there was anything special about bitcoinj, just that it's an example of a wallet engine that's already in use. BIP70 is interesting, indeed, although I still fail to understand why (according to the specs I saw) the PaymentRequest message is signed, but not the Payment message. Because it's intended to be submitted via HTTPS. But what would you sign the message with? Some arbitrary key bound to the transaction? -- New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. http://p.sf.net/sfu/gigenet___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
Hi there, some thoughts in-line: Finally, distributors of consumer wallets can use this research in order to distribute their wallet with policies which may be less prone to Tor-specific attacks. Or leave this out altogether if their audience has different expectations for connecting to Bitcoin. Sure. I guess there will be wallets for all kinds of people in future, sharing a common core that they can customise (this is certainly the vision and general direction for bitcoinj, and it's working out OK). To clarify, my comments above were for mainstream granny-focused wallets. Wallets designed for crypto geeks can and should expose all the knobs to let people run wild. I hear that. But I don't see why mainstream wallets and wallets designed for crypto research should not share a common core. Nor do I understand why having a common core for different types of wallets should be reserved for BitcoinJ. When Bitcoin was pretty new, having a less customizable core did probably have more of a merit in order to achieve network stability through monoculture. But as of today, Bitcoin has proven itself as being capable of allowing a variety of client application to run on the network, so why should the reference implementation not reflect this kind of diversity? The policy the mainstream distribution imposes upon the core can still be rather restrictive. One possible direction to go is to use Tor for writing to the network and use general link encryption and better Bloom filtering for reading it. Thus new transactions would pop out of Tor exits, but there isn't much they can do that's malicious there except mutate them or block them entirely. If you insert the same transaction into the P2P network via say 10 randomly chosen exits, the worst a malicious mutator can do is race the real transaction and that's no different to a malicious P2P node. Even in a world where an attacker has DoS-banned a lot of nodes and now controls your TX submission path entirely, it's hard to see how it helps them. It might deserve some research in order to determine how Tor's privacy guarantees might be impacted if we allow attackers to mess around with exit node choices in a rather predictable and low-cost manner. Unfortunately, I can't think of another (non-Bitcoin) application which puts Tor to a similar test. The nice thing about the above approach is that it solves the latency problems. Startup speed is really an issue for reading from the network: just syncing the block chain is already enough of a speed hit without adding consensus sync as well. But if you're syncing the block chain via the clearnet you can connect to Tor in parallel so that by the time the user has scanned a QR code, verified the details on the screen and then pressed the Pay button, you have a warm connection and can upload the TX through that. It reduces the level of startup time optimisation needed, although Tor consensus download is still too slow even to race a QR code scan at the moment. I think tuning the consensus caching process and switching to a fresh one on the fly might be the way to go. I do agree that hybrid clearnet/Tor approaches come with interesting performance properties. When BIP70 is in use, you wouldn't write the tx to the network yourself but you could download the PaymentRequest and upload the Payment message via an SSLd Tor connection to the merchant. Then malicious exits can only DoS you but not do anything else so there's no need for multiple exit paths simultaneously. BIP70 is interesting, indeed, although I still fail to understand why (according to the specs I saw) the PaymentRequest message is signed, but not the Payment message. But in context of the discussed protocol issues, I think it just moves the issue from the payer to the payee, so it may or may not partially relieve network-related issues, depending on the usage scenario. Best regards, Isidor -- New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. http://p.sf.net/sfu/gigenet ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
[...] I'm confused by this, I run quite a few nodes exclusively on tor and chart their connectivity and have seen no such connection dropping behaviour. In my experience the problem has always been getting bootstrapped. Most nodes hardly give any hidden service nodes in their getaddr. (this has been improved in master by including a set of hidden service seed nodes) But this assumes -onlynet=tor. Tor with exit nodes should be less problematic, unless someone managed to DoSban all the exit nodes as described in the paper (but I've never seen such an attack myself). When refering to getting bootstrapped, do you only mean collecting node addresses, or also syncing blocks? If you're saying the drops in connection counts are likely to be not caused by a DoSban attack on the exit nodes, what could be other reasons to look into? Can you tell me more about how you measured this? [As an aside I agree that there are lots of things to improve here, but the fact that users can in theory be forced off of tor via DOS attacks is not immediately concerning to me because its a conscious choice users would make to abandon their privacy (and the behaviour of the system here is known and intentional). There are other mechanisms available for people to relay their transactions than connecting directly to the bitcoin network; so their choice isn't just abandon privacy or don't use bitcoin at all.] Right, there's something to be said for splitting your own transaction submission from normal P2P networking and transaction relay. (esp for non-SPV wallets which don't inherently leak any information about their addresses) There was a pull request about this for Bitcoin Core one, maybe I closed it unfairly https://github.com/bitcoin/bitcoin/issues/4564 . Great! I find it very interesting to research options for splitting communication between Tor and non-Tor as long as the introduced information leakage between both connection methods can be proved to be nonexistent or negligible. In the case of Bitcoin, this makes me wonder about an attack that could look approximately like this: * Node A connects to Bitcoin using Tor (for submitting transactions) and IPv4 (for all other communication). * Node B strives for direct IPv4 connections with node A * Node B uses the direct IPv4 connections in order to supply Node A with additional peer addresses not supplied to any other nodes * Node B observes these additional peer addresses For transactions submitted to the additional peer addresses supplied by node B, how to prevent that the probability of these originating from node A is higher than for originating from other nodes? For handling block propagation using non-Tor connections, it's probably harder to create information leaks, as the logic for handling disagreement about blocks is pretty well-researched, meaning that it's less important where the blocks come from. Best regards, Isidor -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
[...] And, on the flip side if the host is persistently behind tor, even with some watermarkable behaviour, their privacy is protected. So making sure that hosts can continually use tor (or similar systems) should be the higher priority. (And, of course, not reimplementing tor leverages the millions of dollars of investment and dozens of subject matter experts working on that system). Reimplementing Tor would not only mean to lose all the investment that ran into Tor, but also to lose a large user base. We can see this with TorCoin. Still, the fact that Bitcoin is a use case for Tor which measurably shows some limits where it is not fully clear if Tor or Bitcoin is to be blamed does not only mean that both projects may have to evolve in order to properly solve the issue, but also that the means of interfacing between both projects may have to be extended. Ideally, in a way which does not require to run a separate Tor and/or Bitcoin network in order to work, but which will be generic enough to satisfy both sides' need to still work in a standalone manner. But I do see huge merit in exploring better ways of synergy between the projects. For example, Tor's hardcoded circuit length may be considered as a hack which was only necessary due to the lack of a suitable resource compensation mechanism. Which is something that is available with Bitcoin. Best regards, Isidor -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
[As an aside I agree that there are lots of things to improve here, but the fact that users can in theory be forced off of tor via DOS attacks is not immediately concerning to me because its a conscious choice users would make to abandon their privacy Bitcoin already has a large population of users who have little or no technical skill, it wouldn't surprise me at all if it was found to be the clear majority by now. Assuming success and growth in future, very few users will make any decisions at all about their privacy, they will just accept the defaults. In such a world no consumer wallet is going to directly expose Tor to end users - if used at all it'll just be used behind the scenes. So automated fallback or control over exits would be a concern for such wallets. In order to get more synergy between Bitcoin users of varying skill levels, my suggestion would be a cleaner separation between technical mechanisms and policies (possibly suitable for users without technical skills). Core development would mean providing suitable mechanisms by which it is possible to run Bitcoin on different constraints. This may include ways to handle attacks specific to the Tor/Bitcoin combination. People who like to research what is possible with the protocol can then experiment on how these mechanisms can be used in order to mitigate these attacks. Finally, distributors of consumer wallets can use this research in order to distribute their wallet with policies which may be less prone to Tor-specific attacks. Or leave this out altogether if their audience has different expectations for connecting to Bitcoin. The tricky part is probably to figure out what is the greatest common denominator of what keeps Bitcoin stable and running while still leaving room for customized policies. But I think that separating concerns like this is better than letting a debate about how to mitigate certain Tor-related attacks evolve towards a debate about Tor or not Tor. My gut feeling about this stuff has changed over time. I don't think it'd be a great idea to tie Bitcoin to Tor too deeply, convenient though its infrastructure is. Most apps don't need a whole lot of onion routing - a small amount built in to the p2p layer would be sufficient. Tor is huge, complicated and could be a liability in future. I think it would be very interesting to explore alternatives for Tor. But at this point, completely abandoning Tor would mean that users either have to agree to have their transactions correlated to their IP address, or to trust their transactions to a third party where they are not subject to the security guarantees Bitcoin's logic can provide anymore. In my opinion, it's a rather huge sacrifice. What I find interesting, however, is that a lot of suggestions I see with respect to attacks related to Tor/Bitcoin (including my own) involve some kind of extra effort required for Tor users on Bitcoin in order to protect themselves against these attacks. So, it may be interesting to explore if it is viable to think of Tor's privacy guarantees as coming for free. Going from there, if it cannot be guaranteed to work completely for free, the question would be to what extent the required extra effort should be a shared effort of the network, and to what extent users requiring the improved privacy should use their own resources in order to make it possible. Best regards, Isidor -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
Finally, distributors of consumer wallets can use this research in order to distribute their wallet with policies which may be less prone to Tor-specific attacks. Or leave this out altogether if their audience has different expectations for connecting to Bitcoin. Sure. I guess there will be wallets for all kinds of people in future, sharing a common core that they can customise (this is certainly the vision and general direction for bitcoinj, and it's working out OK). To clarify, my comments above were for mainstream granny-focused wallets. Wallets designed for crypto geeks can and should expose all the knobs to let people run wild. One possible direction to go is to use Tor for writing to the network and use general link encryption and better Bloom filtering for reading it. Thus new transactions would pop out of Tor exits, but there isn't much they can do that's malicious there except mutate them or block them entirely. If you insert the same transaction into the P2P network via say 10 randomly chosen exits, the worst a malicious mutator can do is race the real transaction and that's no different to a malicious P2P node. Even in a world where an attacker has DoS-banned a lot of nodes and now controls your TX submission path entirely, it's hard to see how it helps them. The nice thing about the above approach is that it solves the latency problems. Startup speed is really an issue for reading from the network: just syncing the block chain is already enough of a speed hit without adding consensus sync as well. But if you're syncing the block chain via the clearnet you can connect to Tor in parallel so that by the time the user has scanned a QR code, verified the details on the screen and then pressed the Pay button, you have a warm connection and can upload the TX through that. It reduces the level of startup time optimisation needed, although Tor consensus download is still too slow even to race a QR code scan at the moment. I think tuning the consensus caching process and switching to a fresh one on the fly might be the way to go. When BIP70 is in use, you wouldn't write the tx to the network yourself but you could download the PaymentRequest and upload the Payment message via an SSLd Tor connection to the merchant. Then malicious exits can only DoS you but not do anything else so there's no need for multiple exit paths simultaneously. -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
Hi Gregory, response below quote: Since this attack vector has been discussed, I started making some measurements on how effective it is to connect to Bitcoin using Tor, and I found that the number of connections dropping to near-zero is a situation which occurs rather frequently, which suggests that there is still room to improve on the DoS handling. I'm confused by this, I run quite a few nodes exclusively on tor and chart their connectivity and have seen no such connection dropping behaviour. Can you tell me more about how you measured this? When you say running exclusively on Tor, what do you mean exactly? Do you also connect or allow connections through hidden services? I made outbound connections through Tor exit points the only way to connect to Bitcoin, and increased the number of allowed outbound connection in order to get more meaningful values. Lately, I could see unusual behaviour at: * 2014-11-28 13:14 UTC * 2014-11-25 07:32 UTC * 2014-11-24 13:06 UTC Anything I should look into? [As an aside I agree that there are lots of things to improve here, but the fact that users can in theory be forced off of tor via DOS attacks is not immediately concerning to me because its a conscious choice users would make to abandon their privacy (and the behaviour of the system here is known and intentional). There are other mechanisms available for people to relay their transactions than connecting directly to the bitcoin network; so their choice isn't just abandon privacy or don't use bitcoin at all.] I think this issue is more important than it seems. Firstly, when running Tor-only, there are still attack vectors which make use of the DoS protection deficiencies. Secondly, if we tell people not to connect directly if they want privacy, how do we ensure that these indirect methods will not come with implications for their privacy? Best regards, Isidor -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
[As an aside I agree that there are lots of things to improve here, but the fact that users can in theory be forced off of tor via DOS attacks is not immediately concerning to me because its a conscious choice users would make to abandon their privacy Bitcoin already has a large population of users who have little or no technical skill, it wouldn't surprise me at all if it was found to be the clear majority by now. Assuming success and growth in future, very few users will make any decisions at all about their privacy, they will just accept the defaults. In such a world no consumer wallet is going to directly expose Tor to end users - if used at all it'll just be used behind the scenes. So automated fallback or control over exits would be a concern for such wallets. My gut feeling about this stuff has changed over time. I don't think it'd be a great idea to tie Bitcoin to Tor too deeply, convenient though its infrastructure is. Most apps don't need a whole lot of onion routing - a small amount built in to the p2p layer would be sufficient. Tor is huge, complicated and could be a liability in future. -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
On Thu, Nov 27, 2014 at 2:22 AM, Gregory Maxwell gmaxw...@gmail.com wrote: Since this attack vector has been discussed, I started making some measurements on how effective it is to connect to Bitcoin using Tor, and I found that the number of connections dropping to near-zero is a situation which occurs rather frequently, which suggests that there is still room to improve on the DoS handling. I'm confused by this, I run quite a few nodes exclusively on tor and chart their connectivity and have seen no such connection dropping behaviour. In my experience the problem has always been getting bootstrapped. Most nodes hardly give any hidden service nodes in their getaddr. (this has been improved in master by including a set of hidden service seed nodes) But this assumes -onlynet=tor. Tor with exit nodes should be less problematic, unless someone managed to DoSban all the exit nodes as described in the paper (but I've never seen such an attack myself). Can you tell me more about how you measured this? [As an aside I agree that there are lots of things to improve here, but the fact that users can in theory be forced off of tor via DOS attacks is not immediately concerning to me because its a conscious choice users would make to abandon their privacy (and the behaviour of the system here is known and intentional). There are other mechanisms available for people to relay their transactions than connecting directly to the bitcoin network; so their choice isn't just abandon privacy or don't use bitcoin at all.] Right, there's something to be said for splitting your own transaction submission from normal P2P networking and transaction relay. (esp for non-SPV wallets which don't inherently leak any information about their addresses) There was a pull request about this for Bitcoin Core one, maybe I closed it unfairly https://github.com/bitcoin/bitcoin/issues/4564 . Wladimir -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
I might be mistaken, but it seems to me this paper discusses unintended ways of obtaining the IP addresses of clients involved in transactions on the core Bitcoin network. Tor was mentioned only insofar as it might be one's first thought of how to mitigate this risk, yet Bitcoin over Tor has its own problems that prevent this from being effective. But the primary issues mentioned in the paper are regarding a Bitcoin node in default operation, no? In their new study, researchers at the Laboratory of Algorithmics, Cryptology and Security of the University of Luxembourg have shown that Bitcoin does not protect user's IP address and that it can be linked to the user's transactions in real-time. The basic idea behind these findings is that Bitcoin entry nodes, to which the user's computer connects in order to make a transaction, form a unique identifier for the duration of user's session. This unique pattern can be linked to a user's IP address. Moreover, transactions made during one session, even those made via unrelated pseudonyms, can be linked together. With this method, hackers can reveal up to 60 percent of the IP addresses behind the transactions made over the Bitcoin network. 'This Bitcoin network analysis combined with previous research on transaction flows shows that the level of anonymity in the Bitcoin network is quite low,' explains Dr. Alex Biryukov. M -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
That's what I was trying to say... The researchers are deanonymizing transactions from non-Tor connected hosts. So why are we talking about Tor limitations in response to this? Shouldn't we be discussing how to address the issues in Bitcoin proper? M On 11/27/2014 9:30 PM, Gregory Maxwell wrote: On Thu, Nov 27, 2014 at 5:44 PM, mister...@gmail.com wrote: I might be mistaken, but it seems to me this paper discusses unintended ways of obtaining the IP addresses of clients involved in transactions on the core Bitcoin network. You're mistaken. :) If a node is used exclusively via tor it effectively doesn't have a IP address. (short of bugs of a class that aren't discussed here) The paper is about fingerprinting approaches that probabilistically connect transactions to hosts that you can already identify their IPs. -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
On Fri, Nov 28, 2014 at 12:45 AM, Mistr Bigs mister...@gmail.com wrote: That's what I was trying to say... The researchers are deanonymizing transactions from non-Tor connected hosts. So why are we talking about Tor limitations in response to this? Shouldn't we be discussing how to address the issues in Bitcoin proper? Because if the user does not use tor or an analogous infrastructure (e.g. something else reimplementing tor's functionality) the user can be deanonymized in many different ways. At the end of the day, if I'm listening widely to the network, and your host is regularly the first to hand me your transactions then I can draw reasonably reliable conclusions... and this is true even if there is a complete absence of identifiable characteristics otherwise. And, on the flip side if the host is persistently behind tor, even with some watermarkable behaviour, their privacy is protected. So making sure that hosts can continually use tor (or similar systems) should be the higher priority. (And, of course, not reimplementing tor leverages the millions of dollars of investment and dozens of subject matter experts working on that system). -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
I don't recall being contacted directly, but the attack has been discussed. It relies on a number of conditions. For example, if you are over Tor, they try to kick the machine off Tor, _assuming_ that it will fall back to non-Tor. That's only true for dual stack nodes, which are not really 100% anonymous anyway -- you're operating from your public IP anyway. On Wed, Nov 26, 2014 at 2:47 AM, Jean-Paul Kogelman jeanpaulkogel...@me.com wrote: This paper was just posted on reddit that describes how an attacker can de-anonymize clients on the bitcoin network. It mentions that the core devs were contacted prior to publication. I was just wondering, how many of these issues have already been addressed? Paper (University of Luxembourg): http://orbilu.uni.lu/handle/10993/18679 Kind regards, Jean-Paul -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Jeff Garzik Bitcoin core developer and open source evangelist BitPay, Inc. https://bitpay.com/ -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 Please see also the following: https://cpunks.org//pipermail/cypherpunks/2014-November/005971.html Respect, - -Odinn Jeff Garzik: I don't recall being contacted directly, but the attack has been discussed. It relies on a number of conditions. For example, if you are over Tor, they try to kick the machine off Tor, _assuming_ that it will fall back to non-Tor. That's only true for dual stack nodes, which are not really 100% anonymous anyway -- you're operating from your public IP anyway. On Wed, Nov 26, 2014 at 2:47 AM, Jean-Paul Kogelman jeanpaulkogel...@me.com wrote: This paper was just posted on reddit that describes how an attacker can de-anonymize clients on the bitcoin network. It mentions that the core devs were contacted prior to publication. I was just wondering, how many of these issues have already been addressed? Paper (University of Luxembourg): http://orbilu.uni.lu/handle/10993/18679 Kind regards, Jean-Paul -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development - -- http://abis.io ~ a protocol concept to enable decentralization and expansion of a giving economy, and a new social good https://keybase.io/odinn -BEGIN PGP SIGNATURE- iQEcBAEBCgAGBQJUdgpQAAoJEGxwq/inSG8CBCMIAI8IyyzxbhC0NVY8wyLXaHnW um0HkmrP0bknL0ugjXDXHIBJmadH9uwOT5g1WpJ1siJbjm7nTNn2EXui8EKaX133 SkdZu0IVV5wDZB0OnIDxxx4cyuwNBWbxLh0boVCzydUlZaxQCx88SriKLNj4NrAT oPBuOSL9Z/EsscO8PIh73+t7rdsAQo7koFcwVB8OgjKKATZpAgu4/hwBDoSnhv/U F/X1EcQifg5j2DPmPmJo2/u9PmfHjgDUevw7qJOYNDFMPq4zhi6IC+x2aAXZg0rk jHF79loJ5vueMaU6APVcIQ4izbyzU0y0JaY4Rukq0YkuXCMgZB8BJlS/BPntZdY= =K2tn -END PGP SIGNATURE- -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
Hello there, quote: Please see also the following: https://cpunks.org//pipermail/cypherpunks/2014-November/005971.html I agree about the severity of the Tor/Bitcoin issue, but I see no point in bashing Bitcoin's financial privacy characteristics as the linked pages seem to do. Bitcoin can be useful as a part of a strategy to improve on privacy, but it does not intend to be a run-and-forget solution for doing so. A lot of issues found in this context can actually be traced back to Tor's characteristics already known before. It's just that Bitcoin makes Tor's deficiencies more measurable - before Bitcoin, those interested in researching how Tor performs in an automated context where a much smaller community. In the end, I guess both projects can benefit from the research we can do now. Respect, - -Odinn Jeff Garzik: I don't recall being contacted directly, but the attack has been discussed. It relies on a number of conditions. For example, if you are over Tor, they try to kick the machine off Tor, _assuming_ that it will fall back to non-Tor. That's only true for dual stack nodes, which are not really 100% anonymous anyway -- you're operating from your public IP anyway. Generally, it cannot be said that the attack vector described here is irrelevant for non-dual-stack nodes. An attacker might not be able to collect IP addresses of Tor-only nodes, but he can try to kick the users from all Tor exit nodes he does not control, and proceed with other attacks when a large number of Tor-only users connect through his Tor exit node(s). Since this attack vector has been discussed, I started making some measurements on how effective it is to connect to Bitcoin using Tor, and I found that the number of connections dropping to near-zero is a situation which occurs rather frequently, which suggests that there is still room to improve on the DoS handling. Best regards, Isidor -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
Since this attack vector has been discussed, I started making some measurements on how effective it is to connect to Bitcoin using Tor, and I found that the number of connections dropping to near-zero is a situation which occurs rather frequently, which suggests that there is still room to improve on the DoS handling. I'm confused by this, I run quite a few nodes exclusively on tor and chart their connectivity and have seen no such connection dropping behaviour. Can you tell me more about how you measured this? [As an aside I agree that there are lots of things to improve here, but the fact that users can in theory be forced off of tor via DOS attacks is not immediately concerning to me because its a conscious choice users would make to abandon their privacy (and the behaviour of the system here is known and intentional). There are other mechanisms available for people to relay their transactions than connecting directly to the bitcoin network; so their choice isn't just abandon privacy or don't use bitcoin at all.] -- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
[Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper
This paper was just posted on reddit that describes how an attacker can de-anonymize clients on the bitcoin network. It mentions that the core devs were contacted prior to publication. I was just wondering, how many of these issues have already been addressed? Paper (University of Luxembourg): http://orbilu.uni.lu/handle/10993/18679 http://orbilu.uni.lu/handle/10993/18679 Kind regards, Jean-Paul-- Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=157005751iu=/4140/ostg.clktrk___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
