From: Jonas Schnelli <dev@jonasschnelli•ch>
To: bitcoin-dev@lists•linuxfoundation.org
Subject: Re: [bitcoin-dev] p2p authentication and encryption BIPs
Date: Wed, 25 May 2016 11:36:24 +0200 [thread overview]
Message-ID: <57457218.6060804@jonasschnelli.ch> (raw)
In-Reply-To: <20160524202250.01db6f61@laptop-m1330>
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>> Good point.
>> I have mentioned this now in the BIP but I think the BIP should allow
>> message > 16 MiB.
>> I leave the max. message length up to the implementation while keeping
>> the 4 byte length on the protocol level.
>
> I expect the implementation defined max size to work (SSH 2.0 does this
> after all), but I want to make sure my suggestion is understood
> completely.
>
> There is a length field for the encrypted data, and length field(s)
> inside of the encrypted data to indicate the length of the plaintext
> Bitcoin messages. I am suggesting that the outter (encrypted) length
> field be reduced, which will _not limit_ the length of Bitcoin
> messages. For example, if a 1 GiB Bitcoin message needed to be sent
> and the encrypted length field was 3 bytes - the sender is forced to
> send a minimum of 64 MACs for this message. The tradeoff is allowing
> the receiver to detect malformed data sooner and have a lower max
> buffering window **against** slightly higher bandwidth and CPU
> requirements due to the additional headers+MACs (the CPU requirements
> should primarily be in "finalizing each Poly1305").
Okay. Got your point.
The current BIPs assumption is that an encrypted package/message can
contain 1..n bitcoin messages (a single bitcoin message distributed over
multiple encrypted messages/packages was not specified).
But right, this could make sense.
Let me think this through....
> An alternative way to think about the suggestion is tunnelling Bitcoin
> messages over TLS or SSH. TLS 1.2 has a 2-byte length field and SSH 2.0
> a 4-byte length field, but neither prevents larger Bitcoin messages from
> being tunnelled; the lengths are independent.
TLS/SSH tunneling is already possible with third party software like
stunnel.
Also there is promising projects that would encrypt the traffic "on a
deeper layer" (see CurveCP).
I think what we want is a simple, openssl-independent traffic encryption
built into the core p2p layer.
IMO the risk of screwing up the implementation is moderate.
The implementation is not utterly-complex:
OpenSSH chacha20:
https://github.com/openssh/openssh-portable/blob/0235a5fa67fcac51adb564cba69011a535f86f6b/chacha.c
Chacha20-Poly1305:
https://github.com/openssh/openssh-portable/blob/0235a5fa67fcac51adb564cba69011a535f86f6b/cipher-chachapoly.c
Sure. Before an implementation will be deployed to the endusers it will
require intense cryptoanalysis first.
</jonas>
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prev parent reply other threads:[~2016-05-25 9:36 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
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 [this message]
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