public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Mark van Cuijk <mark@coinqy.com>
To: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] BIP72 amendment proposal
Date: Fri, 12 Sep 2014 22:59:19 +0200	[thread overview]
Message-ID: <06D9FBBD-30DB-4591-A932-B5A19F1D6543@coinqy.com> (raw)
In-Reply-To: <mailman.342174.1410547421.2163.bitcoin-development@lists.sourceforge.net>

On 12 Sep 2014, at 20:43 , bitcoin-development-request@lists.sourceforge.net wrote:

> Specifically relevant here:
> http://security.stackexchange.com/questions/34796/truncating-the-output-of-sha256-to-128-bits.
> 
> If you're going to truncate though, why not just leave the amount of
> bits up the the person generating the QR code? The client simply takes
> the hash prefix (any length up to full 256-bits) and makes sure it's a
> strict prefix of the actual hash of the payment request.

If you do so, please make sure the length of the hash is included in the PaymentDetails/PaymentRequest. If someone parses the URI and doesn’t have an authenticated way of knowing the expected length of the hash, a MITM attacker can just truncate the hash to lower security.

/Mark


       reply	other threads:[~2014-09-12 20:59 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.342174.1410547421.2163.bitcoin-development@lists.sourceforge.net>
2014-09-12 20:59 ` Mark van Cuijk [this message]
2014-09-13  8:53   ` [Bitcoin-development] BIP72 amendment proposal Wladimir
     [not found] <mailman.341412.1410515709.2178.bitcoin-development@lists.sourceforge.net>
2014-09-12 10:11 ` Mark van Cuijk
2014-09-12 11:07   ` Andreas Schildbach
2014-09-12 13:49     ` Mike Hearn
2014-09-12 14:15       ` Jeff Garzik
2014-09-12 14:36       ` Andreas Schildbach
2014-09-12 15:25         ` Christophe Biocca
2014-09-12 15:33           ` Christophe Biocca
2014-09-12 15:37             ` Mike Hearn
2014-09-12 16:31               ` Mike Hearn
2014-09-12 18:43                 ` Aaron Voisine
2014-09-15  7:43                   ` Andreas Schildbach
2014-09-15  7:12                 ` Andreas Schildbach
2014-09-12 15:36         ` Mike Hearn
2014-09-12  9:29 Andreas Schildbach
2014-09-12  9:55 ` Wladimir

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=06D9FBBD-30DB-4591-A932-B5A19F1D6543@coinqy.com \
    --to=mark@coinqy.com \
    --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