Bitcoin Forum

Bitcoin XT contains an unmentioned addition which periodically downloads
lists of Tor IP addresses for blacklisting, this has considerable privacy
implications for hapless users which are being prompted to use the
software. The feature is not clearly described, is enabled by default,
and has a switch name which intentionally downplays what it is doing
(disableipprio). Furthermore these claimed anti-DoS measures are
trivially bypassed and so offer absolutely no protection whatsoever.

Connections are made over clearnet even when using a proxy or
onlynet=tor, which leaks connections on the P2P network with the real
location of the node. Knowledge of this traffic along with uptime metrics
from bitnodes.io can allow observers to easily correlate the location and
identity of persons running Bitcoin nodes. Denial of service can also be
used to crash and force a restart of an interesting node, which will
cause them to make a new request to the blacklist endpoint via the
clearnet on relaunch at the same time their P2P connections are made
through a proxy. Requests to the blacklisting URL also use a custom
Bitcoin XT user agent which makes users distinct from other internet
traffic if you have access to the endpoints logs.


https://github.com/bitcoinxt/bitcoinxt/commit/73c9efe74c5cc8faea9c2b2c785a2f5b68aa4c23

Please stop this blatant promotion Bitcoin XT by misinforming community.

BitPay supports BIP101 (large blocks), but not XT!

Besides block size increase, Bitcoin XT client has other unmentioned features that affect privacy.

Proof:

Spurce: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010379.html

Could you please stop spreding the lie, that it is unmentioned?
It is mentioned on the official website:
https://bitcoinxt.software/patches.html

Could you please stop spreding the lie, that it is unmentioned?
It is mentioned on the official website:
https://bitcoinxt.software/patches.html

http://s2.postimg.org/agdjmvqhl/zbitpaybitcoinxt_Untitled.png (https://twitter.com/spair/status/634174754879078400)

It is inevitable. All major players will support XT because it scales their operations. I'm pretty sure Mike and Gavin have been approached by them to release the code in the wild so they can use it. The free market will prevail.

It's true, it is mentioned. Does that improve matters? Tor usage with XT is documented to be compromised in XT, how is that a good thing? Please explain.

Was it mentioned from the first day of XT release ?
In the news and discussions there were statements that XT's only difference from Core is increased block size.

And btw. there is an only-bigblocks-version:
https://github.com/bitcoinxt/bitcoinxt/tree/only-bigblocks

This is not the version available for download from official XT site.

Official XT version has a backdoor that allows NSA/CIA and other parties to start ddos attack that blocks Tor and de-anonymizes users.

data = urllib2.urlopen("https://check.torproject.org/exit-addresses").read()

I don't find, where it is called. Can you show me?

That's indeed a bitch move OP, why say AKA? Your thread title is incorrect, I wonder if you will change it.
Bitpay hasn't said they support XT or Core by saying BIP101, but one would assume they mean Core+BIP101.

This is not the version available for download from official XT site.

Official XT version has a backdoor that allows NSA/CIA and other parties to start ddos attack that blocks Tor and de-anonymizes users.

There isn't :)
It is simply not true, this place if full of trolls and ignorants that simply doesn't know and doesn't want to understand anything about the topic.

It's a feature against dos attack, and if you don't like it? Bam! Just add -disableipprio before running the node/client. OMG!!!

Move on.

Fine. Here some clarifications. Is that better?

There isn't :)
It is simply not true, this place if full of trolls and ignorants that simply doesn't know and doesn't want to understand anything about the topic.

It's a feature against dos attack, and if you don't like it? Bam! Just add -disableipprio before running the node/client. OMG!!!
Move on.

@meono, you can comment it from your original forum account

@meono, you can comment it from your original forum account


The most of the users are not aware about -disableipprio switch and this is not excuse.
XT client has Anti-DDOS tor blocking feature enabled by default which means that user's privacy can be compromised.

No it does not, Show me the code that does what you say. So we can explain it to you.

Can you comment on this ?
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010379.html

        vSeeds.push_back(CDNSSeedData("bitcoin.sipa.be", "seed.bitcoin.sipa.be")); // Pieter Wuille
        vSeeds.push_back(CDNSSeedData("bluematt.me", "dnsseed.bluematt.me")); // Matt Corallo
        vSeeds.push_back(CDNSSeedData("dashjr.org", "dnsseed.bitcoin.dashjr.org")); // Luke Dashjr
        vSeeds.push_back(CDNSSeedData("bitcoinstats.com", "seed.bitcoinstats.com")); // Christian Decker
        vSeeds.push_back(CDNSSeedData("xf2.org", "bitseed.xf2.org")); // Jeff Garzik
        vSeeds.push_back(CDNSSeedData("bitcoin.jonasschnelli.ch", "seed.bitcoin.jonasschnelli.ch")); // Jonas Schnelli

http://s2.postimg.org/agdjmvqhl/zbitpaybitcoinxt_Untitled.png (https://twitter.com/spair/status/634174754879078400)

It is inevitable. All major players will support XT because it scales their operations. I'm pretty sure Mike and Gavin have been approached by them to release the code in the wild so they can use it. The free market will prevail.

Can you comment on this ?
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010379.html

You seem to think I hate Tor. I am actually the maintainer of a full blown Tor implementation (Orchid). I've done a lot of work on integrating it into bitcoinj and I'm basically the only guy who can actually move the needle on Tor/Bitcoin usage, by enabling the use of it by default in consumer wallets that have hundreds of thousands of installs. We're not there yet (it's still too slow) but we're a lot closer than before.

This doesn't change the fact that Tor is heavily abused. It can be useful but it's a frequent source of attacks of all kinds. So finding ways to get the good without the bad involves some tricky coding.

Below, you say "anyone can jam the network with just two IP addresses". Yes, that's unfortunate isn't it. I've been sounding the alarm about Bitcoin Core's poor DoS protection for years. Nobody listened, that's why I have now written a new anti-DoS system that can handle this sort of thing. It starts by clustering and deprioritising Tor because we've seen actual jamming attacks that came through Tor, and because using it is a lot safer and more convenient for an attacker than using your own IP addresses or using a botnet. But it absolutely should be extended to have more advanced heuristics. Instead of whinging that (gasp) loading a file from a web server is "insane", maybe you should be writing code instead.

There isn't :)
It's a feature against dos attack, and if you don't like it? Bam! Just add -disableipprio before running the node/client. OMG!!!

That works in a way that stops your own node from discriminating against Tor traffic, it doesn't prevent anyone using the feature from discriminating against you ....

Can you comment on this ?
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010379.html

Please stop misinforming community. What are you doing is blatant manipulation in order to promote Bitcoin XT.

BitPay supports BIP101 (large blocks), but not XT!

--snip--

In our opinion, BIP 101 should be pulled into Bitcoin Core.

Currently, the block size limit is hard-coded to 1mb, which constrains overall transaction throughput. BIP101 proposes to increase that limit to 8mb after January of 2016 when a supermajority (>75%) of the blocks being mined indicate they support the increase. The limit on block size will double every two years after that until it reaches 8gb in 2036.

--snip--

In summary, we believe BIP 101 will safeguard Bitcoin’s decentralized nature while providing a reliable, immediate path toward greater network throughput, and we would like to express our support for merging BIP 101 into Bitcoin Core.

The tweet mentioned in the OP links to a blog post (https://medium.com/@spair/increasing-the-block-size-limit-85ff236fc516)

A few snippets:

From the looks of it they are supporting the hard fork that will happen once 75% of the miners (based on blocks found) accept BIP 101. I don't think it is entirely accurate to say that BitPay is not supporting XT.

I think it would be more accurate to say that BitPay is supporting Bitcoin Core to have the same rules that XT will have regarding larger blocks.

IF the node is under a dos attack.

Move on.

This is not the version available for download from official XT site.

Official XT version has a backdoor that allows NSA/CIA and other parties to start ddos attack that blocks Tor and de-anonymizes users.