public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Phantomcircuit <phantomcircuit@covertinferno.org>
To: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] CAddrMan: Stochastic IP address manager
Date: Tue, 31 Jan 2012 04:21:09 -0500	[thread overview]
Message-ID: <4F27B285.6060105@covertinferno.org> (raw)
In-Reply-To: <CAFHuXuZ78y3nHfuKBgjO1j+bNsdnbngDee_Xii4xGhUshJqtZQ@mail.gmail.com>

[-- Attachment #1: Type: text/plain, Size: 2305 bytes --]

On 01/30/2012 11:33 PM, Michael Hendricks wrote:
> On Mon, Jan 30, 2012 at 7:05 PM, Gavin Andresen <gavinandresen@gmail.com> wrote:
>> Given the randomness in Pieter's design, that seems extremely unlikely
>> / difficult to do. Is it possible to do a back-of-the-envelope
>> calculation to figure out what percentage of nodes on the network an
>> attacker would have to control to have a (say) 1% chance of a
>> successful Sybil attack?
> The randomness prevents finely crafted attacks since an attacker can't
> predict which bucket his address ends up in.  I don't think it helps
> against brute force attacks though.  If 60% of the network's nodes are
> controlled by an evil botnet, 60% of the nodes we pull out of the
> address manager point to the attacker.  If a client has 8 connections
> to the network, a Sybil attack would succeed 1.7% of the time.  At
> current network size, 60% of listening nodes is 2,800; only 2-5% of a
> decent botnet.
>
> Nodes that accept incoming connections are far less vulnerable, since
> the probability of success decreases exponentially with the number of
> connections.  95% botnet control with 125 connections has 10^-6 chance
> of success.
>
> Perhaps we could add a command-line option for increasing the maximum
> number of outbound connections.  That way, nodes unable to accept
> incoming connections can easily decrease their susceptibility to Sybil
> attack.
>
>> I've also been wondering if it is time to remove the IRC bootstrapping
>> mechanism; it would remove a fair bit of code and we'd stop getting
>> reports that various ISPs tag bitcoin as malware.  When testing the
>> list of built-in bootstrapping IP addresses I always connect fairly
>> quickly, and the DNS seeding hosts seems to be working nicely, too.
> I think it should be disabled by default one release after the new
> address manager is released.  That way, we're not changing too many
> parts of the bootstrapping process at once.
>
> As an aside, I can't help but wonder whether ISPs blocking IRC traffic
> filters some botnets out of the IRC bootstrapping channels; keeping
> them more "pure".
>
If the number of outbound connections is increased the delay of
transaction broadcast code needs to be improved to avoid a broadcast storm.


[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4515 bytes --]

      parent reply	other threads:[~2012-01-31  9:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30  2:31 [Bitcoin-development] CAddrMan: Stochastic IP address manager Pieter Wuille
2012-01-30  2:37 ` Luke-Jr
2012-01-30 16:53 ` Michael Hendricks
2012-01-31  2:05   ` Gavin Andresen
2012-01-31  2:07     ` Luke-Jr
2012-01-31  2:57     ` Gregory Maxwell
2012-01-31  8:19       ` grarpamp
2012-01-31 13:50       ` solar
2012-01-31  4:33     ` Michael Hendricks
2012-01-31  7:17       ` Gregory Maxwell
2012-01-31 15:06         ` Michael Hendricks
2012-01-31 15:07         ` Michael Hendricks
2012-01-31  9:21       ` Phantomcircuit [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4F27B285.6060105@covertinferno.org \
    --to=phantomcircuit@covertinferno.org \
    --cc=bitcoin-development@lists.sourceforge.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox