From: Andreas Schildbach <andreas@schildbach•de>
To: bitcoin-development@lists•sourceforge.net
Subject: Re: [Bitcoin-development] BIP 38 NFC normalisation issue
Date: Tue, 15 Jul 2014 15:19:29 +0200 [thread overview]
Message-ID: <lq39p1$gff$1@ger.gmane.org> (raw)
In-Reply-To: <CAObn+gfbH61kyv_ttT4vsQuNFRWLB5H3xaux7GQ0co82ucO_eA@mail.gmail.com>
I think generally control-characters (such as \u0000) should be
disallowed in passphrases. (Even the use of whitespaces is very
questionable.)
I'm ok with allowing pile-of-poo's. On mobile phones there is keyboards
just containing emoticons -- why not allow those? Assuming NFC works of
course.
On 07/15/2014 03:07 PM, Eric Winer wrote:
> I don't know for sure if the test vector is correct NFC form. But for
> what it's worth, the Pile of Poo character is pretty easily accessible
> on the iPhone and Android keyboards, and in this string it's already in
> NFC form (f09f92a9 in the test result). I've certainly seen it in
> usernames around the internet, and wouldn't be surprised to see it in
> passphrases entered on smartphones, especially if the author of a
> BIP38-compatible app includes a (possibly ill-advised) suggestion to
> have your passphrase "include special characters".
>
> I haven't seen the NULL character on any smartphone keyboards, though -
> I assume the iOS and Android developers had the foresight to know how
> much havoc that would wreak on systems assuming null-terminated strings.
> It seems unlikely that NULL would be in a real-world passphrase entered
> by a sane user.
>
>
> On Tue, Jul 15, 2014 at 8:03 AM, Mike Hearn <mike@plan99•net
> <mailto:mike@plan99•net>> wrote:
>
> [+cc aaron]
>
> We recently added an implementation of BIP 38 (password protected
> private keys) to bitcoinj. It came to my attention that the third
> test vector may be broken. It gives a hex version of what the NFC
> normalised version of the input string should be, but this does not
> match the results of the Java unicode normaliser, and in fact I
> can't even get Python to print the names of the characters past the
> embedded null. I'm curious where this normalised version came from.
>
> Given that "pile of poo" is not a character I think any sane user
> would put into a passphrase, I question the value of this test
> vector. NFC form is intended to collapse things like umlaut control
> characters onto their prior code point, but here we're feeding the
> algorithm what is basically garbage so I'm not totally surprised
> that different implementations appear to disagree on the outcome.
>
> Proposed action: we remove this test vector as it does not represent
> any real world usage of the spec, or if we desperately need to
> verify NFC normalisation I suggest using a different, more realistic
> test string, like Zürich, or something written in Thai.
>
>
>
> Test 3:
>
> * Passphrase ϓ␀𐐀💩 (\u03D2\u0301\u0000\U00010400\U0001F4A9; GREEK
> UPSILON WITH HOOK <http://codepoints.net/U+03D2>, COMBINING
> ACUTE ACCENT <http://codepoints.net/U+0301>, NULL
> <http://codepoints.net/U+0000>, DESERET CAPITAL LETTER LONG I
> <http://codepoints.net/U+10400>, PILE OF POO
> <http://codepoints.net/U+1F4A9>)
> * Encrypted key:
> 6PRW5o9FLp4gJDDVqJQKJFTpMvdsSGJxMYHtHaQBF3ooa8mwD69bapcDQn
> * Bitcoin Address: 16ktGzmfrurhbhi6JGqsMWf7TyqK9HNAeF
> * Unencrypted private key (WIF):
> 5Jajm8eQ22H3pGWLEVCXyvND8dQZhiQhoLJNKjYXk9roUFTMSZ4
> * /Note:/ The non-standard UTF-8 characters in this passphrase
> should be NFC normalized to result in a passphrase
> of0xcf9300f0909080f09f92a9 before further processing
>
>
>
>
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next prev parent reply other threads:[~2014-07-15 13:19 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-15 12:03 Mike Hearn
2014-07-15 13:07 ` Eric Winer
2014-07-15 13:19 ` Andreas Schildbach [this message]
2014-07-15 13:32 ` Michael Wozniak
2014-07-15 15:13 ` Brooks Boyd
2014-07-15 18:20 ` Mike Hearn
2014-07-15 22:23 ` Aaron Voisine
2014-07-16 9:12 ` Mike Hearn
2014-07-16 9:17 ` Andreas Schildbach
2014-07-16 9:29 ` Mike Hearn
2014-07-16 10:46 ` Andreas Schildbach
2014-07-16 11:04 ` Andreas Schildbach
2014-07-16 21:06 ` Aaron Voisine
2014-07-16 22:02 ` Andreas Schildbach
2014-07-16 22:22 ` Andreas Schildbach
2014-07-17 10:59 ` Mike Hearn
2014-07-17 11:27 ` Andreas Schildbach
2014-07-16 12:38 ` Wladimir
2014-07-15 15:17 ` Jeff Garzik
2014-07-15 15:20 ` Mike Hearn
2014-07-15 15:32 ` Andreas Schildbach
2014-07-15 15:53 ` Jeff Garzik
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