From: Eric Voskuil <eric@voskuil•org>
To: Tom <tomz@freedommail•ch>, bitcoin-dev@lists•linuxfoundation.org
Subject: Re: [bitcoin-dev] p2p authentication and encryption BIPs
Date: Wed, 23 Mar 2016 14:40:50 -0700 [thread overview]
Message-ID: <56F30D62.4090409@voskuil.org> (raw)
In-Reply-To: <1983116.UNQS71VxHo@garp>
[-- Attachment #1: Type: text/plain, Size: 2760 bytes --]
On 03/23/2016 01:36 PM, Tom via bitcoin-dev wrote:
> On Wednesday 23 Mar 2016 16:24:12 Jonas Schnelli via bitcoin-dev wrote:
> * why would you not allow encryption on non-pre-approved connections?
Agree
> * we just removed (ssl) encryption from the JSON interface, how do you suggest
> this encryption to be implemented without openSSL?
CurveCP
> * What is the reason for using the p2p code to connect a wallet to a node?
> I suggest using one of the other connection methods to connect to the node.
> This avoids a change in the bitcoin protocol for a very specific usecase.
Agree, P2P and client-server protocols are distinct use-cases. Missing
this distinction is the root cause of problems with the bloom filters
feature.
> * Why do you want to do a per-message encryption (wrapping the original)?
> Smaller messages that contain predictable content and are able to be matched
> to the unencrypted versions on the wire send to other nodes will open this
> scheme up to various old statistical attacks.
Privacy cannot currently be achieved unless the server is trusted. In
most wallet scenarios that's not a reasonable assumption unless one
controls the full node. So this is only useful in the case where the
wallet is trusting a remote server, and as you point out - message
encryption is weak in this case. In a trustless server scenario
encryption would be unnecessary overhead.
>> Responding peers must ignore (banning would lead to fingerprinting) the
> requesting peer after 5 unsuccessfully authentication tries to avoid resource
> attacks.
>
> Any implementation of that kind would itself again be open to resource
> attacks.
> Why 5? Do you want to allow a node to make a typo?
Agree, denial of service protection can and should be much more flexible
than this. It's not necessary to incorporate DoS protection into a
protocol. I think maybe this stems from the ill-advised attempt at
messaging reliability.
>> To ensure that no message was dropped or blocked, the complete communication
> must be hashed (sha256). Both peers keep the SHA256 context of the encryption
> session. The complete <code>enc</code> message (leaving out the hash itself)
> must be added to the hash-context by both parties. Before sending a
> <code>enc</code> command, the sha256 context will be copied and finalized.
>
> You write "the complete communication must be hashed" and every message has a
> hash of the state until it is at that point.
> I think you need to explain how that works specifically.
Also, this gets into the area of messaging reliability. This is
certainly not something I would recommend for a P2P protocol optimized
for maintaining a cache of public data.
e
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 473 bytes --]
next prev parent reply other threads:[~2016-03-23 21:40 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-23 15:24 Jonas Schnelli
2016-03-23 16:44 ` Tier Nolan
2016-03-23 20:36 ` Tom
2016-03-23 21:40 ` Eric Voskuil [this message]
2016-03-23 21:55 ` Jonas Schnelli
2016-03-25 10:36 ` Tom
2016-03-25 18:43 ` Jonas Schnelli
2016-03-25 20:42 ` Tom
2016-03-26 9:01 ` Jonas Schnelli
2016-03-26 23:23 ` James MacWhyte
2016-03-27 11:58 ` Jonas Schnelli
2016-03-27 17:04 ` James MacWhyte
2016-03-24 0:37 ` Sergio Demian Lerner
2016-03-24 2:16 ` Luke Dashjr
2016-03-24 17:20 ` Chris
2016-03-25 10:41 ` Tom
2016-03-25 7:17 ` Lee Clagett
2016-03-25 10:17 ` Jonas Schnelli
2016-04-01 21:09 ` Jonas Schnelli
2016-04-09 19:40 ` Lee Clagett
2016-05-18 8:00 ` Jonas Schnelli
2016-05-25 0:22 ` Lee Clagett
2016-05-25 9:36 ` Jonas Schnelli
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=56F30D62.4090409@voskuil.org \
--to=eric@voskuil$(echo .)org \
--cc=bitcoin-dev@lists$(echo .)linuxfoundation.org \
--cc=tomz@freedommail$(echo .)ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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