public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: "Jorge Timón" <jtimon@jtimon.cc>
To: Gavin Andresen <gavinandresen@gmail.com>
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Time to worry about 80-bit collision attacks or not?
Date: Mon, 11 Jan 2016 21:32:15 +0100	[thread overview]
Message-ID: <CABm2gDrQx-ETyCk1XOCGKwsLeTQU_gPG_Gpjx=bbf2qHpE1u=w@mail.gmail.com> (raw)
In-Reply-To: <CABsx9T0WRXz54LZnyU7Fr=_ZgwF5armj0Z8uwYcFy2x+BWooxg@mail.gmail.com>

On Fri, Jan 8, 2016 at 4:50 PM, Gavin Andresen via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> And to fend off the messag that I bet somebody is composing right now:
>
> Yes, I know about a "security first" mindset.  But as I said earlier in the
> thread, there is a tradeoff here between crypto strength and code
> complexity, and "the strength of the crypto is all that matters" is NOT
> security first.

If the crypto code is properly encapsulated, the code complexity costs
of choosing one hashing function over another should be non-existent.
You made the space argument which is valid, but in my opinion code
complexity shouldn't be a valid concern in this discussion.

As a maybe uninteresting anecdote, I proposed the asset IDs in
https://github.com/ElementsProject/elements/tree/alpha-0.10-multi-asset
to do the same ```ripemd160 . sha256``` choice that Mark Friedenbach
had proposed and I had approved for
https://github.com/jtimon/freimarkets/blob/master/doc/freimarkets_specs.org#asset-tags
. More humble than me, he admitted he had made a design mistake much
earlier than me, who (maybe paradoxically) probably had less knowledge
for making crypto choices at the low level. In the end I was convinced
with examples I failed to write down for documentation and can't
remember.

That's not to say I have anything to say in this debate other than
code complexity (which I do feel qualified to talk about) shouldn't be
a concern in this debate. Just want to focus the discussion on what it
should be: security vs space tradeoff.
Since I am admittedly in doubt, I tend to prefer to play safe, but
neither my feelings nor my anecdote are logical arguments and should,
therefore, be ignored for any conclusions in the ```ripemd160 .
sha256``` vs sha256d debate. Just like you non-sequitor "sha256d will
lead to more code complexity", if anything, sha256d should be simpler
than ```ripemd160 . sha256``` (but not simpler enough that it matters
much).


  parent reply	other threads:[~2016-01-11 20:32 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-07 19:02 [bitcoin-dev] Time to worry about 80-bit collision attacks or not? Gavin Andresen
2016-01-07 19:13 ` Matt Corallo
2016-01-07 19:19 ` Adam Back
2016-01-07 20:56   ` Dave Scotese
2016-01-07 21:06     ` Gavin Andresen
2016-01-07 22:56       ` Ethan Heilman
2016-01-07 23:39         ` Gavin Andresen
2016-01-08  1:26           ` Matt Corallo
2016-01-08  1:54             ` Gavin Andresen
2016-01-08 17:38               ` Pieter Wuille
2016-01-08 18:41               ` Peter Todd
2016-01-07 20:40 ` Ethan Heilman
2016-01-07 23:52 ` Pieter Wuille
2016-01-08  1:00   ` Gavin Andresen
2016-01-08  1:27     ` Watson Ladd
2016-01-08  3:30   ` Rusty Russell
2016-01-08  3:41     ` Matt Corallo
2016-01-08 12:02       ` Rusty Russell
2016-01-08 12:38         ` Gavin Andresen
2016-01-08 14:34           ` Watson Ladd
2016-01-08 15:26             ` Adam Back
2016-01-08 15:33           ` Anthony Towns
2016-01-08 15:46             ` Gavin Andresen
2016-01-08 15:50               ` Gavin Andresen
2016-01-08 15:59                 ` Gavin Andresen
2016-01-11 20:32                 ` Jorge Timón [this message]
2016-01-08 16:06               ` Gavin Andresen
2016-01-11  3:57               ` Rusty Russell
2016-01-11  6:57                 ` Peter Todd
2016-01-11 23:57               ` Tier Nolan
2016-01-12  0:00                 ` Tier Nolan
2016-01-12 12:08                   ` Gavin Andresen
2016-01-12 23:22                     ` Zooko Wilcox-O'Hearn
2016-01-08 18:52     ` Peter Todd

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='CABm2gDrQx-ETyCk1XOCGKwsLeTQU_gPG_Gpjx=bbf2qHpE1u=w@mail.gmail.com' \
    --to=jtimon@jtimon.cc \
    --cc=bitcoin-dev@lists.linuxfoundation.org \
    --cc=gavinandresen@gmail.com \
    /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