From: "Raystonn ." <raystonn@hotmail•com>
To: "Peter Todd" <pete@petertodd•org>
Cc: Bitcoin Dev <bitcoin-development@lists•sourceforge.net>,
"Patrick Mccorry \(PGR\)" <patrick.mccorry@newcastle•ac.uk>
Subject: Re: [Bitcoin-development] New attack identified and potential solution described: Dropped-transaction spam attack against the blocksize limit
Date: Mon, 8 Jun 2015 14:40:17 -0700 [thread overview]
Message-ID: <COL131-DS227FCC3AAB9F46ED79E97CCDBF0@phx.gbl> (raw)
In-Reply-To: <20150608213336.GA19826@muck>
> the only way a transaction can be removed from a Bitcoin Core mempool is
> through it getting mined, double-spent, or the node restarting.
Right. And that results in some transactions with insufficient fees getting
dropped today after many hours.
> The protection that we have against that attack is that you need access to
> a lot of bitcoins to pay enough fees.
That's no protection against a well-funded private and/or public entity.
Without the block size limit, this attack doesn't exist. It would simply
result in a transfer of wealth from spammer to miners, which is a nicely
antifragile response for the Bitcoin network.
-----Original Message-----
From: Peter Todd
Sent: Monday, June 08, 2015 2:33 PM
To: Raystonn .
Cc: Patrick Mccorry (PGR) ; Bitcoin Dev
Subject: Re: [Bitcoin-development] New attack identified and potential
solution described: Dropped-transaction spam attack against the blocksize
limit
> > there is no memory pool cap currently
>
> Real hardware does not have an infinite amount of RAM. Memory pool sizes
> cannot grow unbounded. Some transactions with insufficient fees do get
> dropped today after many hours.
Actually they don't, which is an unfortunate problem with the existing
mempool implementation; the only way a transaction can be removed from a
Bitcoin Core mempool is through it getting mined, double-spent, or the
node restarting.
The protection that we have against that attack is that you need access
to a lot of bitcoins to pay enough fees. With the 0.01mBTC/KB minimum
relay fee and $230 USD/BTC that works out to about $2.3kUSD/GB of ram
consumed, and furthermore, actually getting that many transactions to
propagate over the network is non-trivial. (no, I'm not going to tell
you how)
The obvious solution is to cap the size of the mempool and evict
transactions lowest fee/KB first, but if you do that they you (further)
break zeroconf security. On the other hand, if you don't break zeroconf
security an attacker can prevent reasonable fee transactions from
propagating.
I probably should get around to fixing this...
next prev parent reply other threads:[~2015-06-08 21:40 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-08 0:36 [Bitcoin-development] Block Size Experiment Underway Tom Harding
2015-06-08 20:07 ` [Bitcoin-development] New attack identified and potential solution described: Dropped-transaction spam attack against the block size limit Raystonn .
[not found] ` <AD4A025F-D782-4094-9CBC-EBEF0DD04838@newcastle.ac.uk>
2015-06-08 21:14 ` Raystonn .
2015-06-08 21:33 ` Peter Todd
2015-06-08 21:40 ` Raystonn . [this message]
[not found] ` <4A74E0B9-869E-448A-BFC7-7FD2F50F142F@newcastle.ac.uk>
2015-06-08 22:26 ` Peter Todd
[not found] ` <7E7DF414-6DDB-48A6-9199-D6883209B67D@newcastle.ac.uk>
2015-06-08 21:33 ` Raystonn .
2015-06-08 21:44 ` Peter Todd
2015-06-08 22:01 ` [Bitcoin-development] New attack identified and potential solution described: Dropped-transaction spam attack against the blocksize limit Raystonn .
2015-06-08 22:07 ` Btc Drak
2015-06-08 22:10 ` Raystonn .
2015-06-08 22:18 ` Peter Todd
2015-06-08 22:46 ` Raystonn .
2015-06-08 22:06 ` [Bitcoin-development] New attack identified and potential solution described: Dropped-transaction spam attack against the block size limit Bob McElrath
2015-06-08 22:28 ` Peter Todd
2015-06-09 9:33 ` Loi Luu
2015-06-09 13:36 ` Gavin Andresen
2015-06-09 14:18 ` Tier Nolan
2015-06-09 17:52 ` Raystonn .
2015-06-09 18:25 ` Gavin Andresen
2015-06-09 19:03 ` Raystonn .
2015-06-20 3:49 ` David Vorick
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