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From: Zooko Wilcox-OHearn <zooko@leastauthority.com>
To: Pieter Wuille <pieter.wuille@gmail.com>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] [softfork proposal] Strict DER signatures
Date: Thu, 22 Jan 2015 22:41:47 +0000	[thread overview]
Message-ID: <CAM_a8Jzt=Q8m=-7wur1UdscqQRQmg+TBFNtneUtRH3nh+TOTDQ@mail.gmail.com> (raw)
In-Reply-To: <CAPg+sBhk7F2OHT64i2LNSjv8DR5tD3RJkLJGzPGZW8OPQTCjQw@mail.gmail.com>

.Hi there. Thank you for your work on this.

I've looked over https://gist.github.com/sipa/5d12c343746dad376c80 and
https://github.com/sipa/bitcoin/commit/bipstrictder . I didn't
actually audit the included reference implementation of
IsValidSignatureEncoding(), and I didn't check whether the test
vectors in https://github.com/sipa/bitcoin/commit/f94e806f8bfa007a3de4b45fa3c9860f2747e427
exercise all of the branches that are changed by this patch.

I have the following comments:

* It seems like a good idea to do this.

* I don't see any problem with using the upgrade mechanism from BIP 34
for this. It's cool! I'm happy that such a mechanism seems to work in
practice.

* Should the bipstrictder give a rationale or link to why accept the
0-length sig as correctly-encoded-but-invalid? I guess the rationale
is an efficiency issue as described in the log entry for
https://github.com/sipa/bitcoin/commit/041f1e3597812c250ebedbd8f4ef1565591d2c34
.

* Does this mean there are still multiple ways to encode a correctly
encoded but invalid signature, one of which is the 0-length string?
Would it make sense for this change to also treat any *other*
correctly-encoded-but-invalid sig (besides the 0-length string) as
incorrectly-encoded? Did I just step in some BIP62?

* It would be good to verify that all the branches of the new
IsDERSignature() from
https://github.com/sipa/bitcoin/commit/0c427135151a6bed657438ffb2e670be84eb3642
are tested by the test vectors in
https://github.com/sipa/bitcoin/commit/f94e806f8bfa007a3de4b45fa3c9860f2747e427
. Eyeballing it, there are about 20 branches touched by the patch, and
about 24 new test vectors.

* It would be good to finish the TODOs in
https://github.com/sipa/bitcoin/commit/b7986119a5d41337fea1e83804ed6223438158ec
so that it was actually testing the upgrade behavior.

* missing comment:
https://github.com/sipa/bitcoin/commit/e186f6a80161f9fa45fbced82ab1d22f081b942c#commitcomment-9406643

Okay, that's all I've got. Hope it helps! Thanks again for your good work!

Regards,

Zooko



  parent reply	other threads:[~2015-01-22 23:08 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-21  0:35 [Bitcoin-development] [softfork proposal] Strict DER signatures Pieter Wuille
2015-01-21  4:45 ` Rusty Russell
2015-01-21 16:49   ` Pieter Wuille
2015-01-21 19:10 ` Peter Todd
2015-01-21 19:29 ` Douglas Roark
2015-01-21 20:30   ` Pieter Wuille
2015-01-21 20:39     ` Douglas Roark
2015-01-21 20:37   ` Gavin Andresen
2015-01-21 20:52     ` Douglas Roark
2015-01-21 21:22     ` Pieter Wuille
2015-01-21 20:27 ` Andrew Poelstra
2015-01-21 22:57 ` Dave Collins
2015-01-22  0:32 ` Rusty Russell
2015-01-22  3:12   ` David Vorick
2015-01-22  4:18   ` Matt Whitlock
2015-01-22  4:20     ` Pieter Wuille
2015-01-25 14:34   ` Pieter Wuille
2015-01-25 14:48     ` Gregory Maxwell
2015-02-03  0:44       ` Pieter Wuille
2015-02-03  2:21         ` Gregory Maxwell
2015-02-03 12:00         ` Wladimir
2015-02-03 14:30           ` Alex Morcos
2015-02-03 18:15           ` Pieter Wuille
2015-02-03 18:19             ` Gavin Andresen
2015-02-03 19:22               ` Jeff Garzik
2015-02-03 23:38             ` Pieter Wuille
2015-01-22 22:41 ` Zooko Wilcox-OHearn [this message]
2015-01-25 16:57   ` Pieter Wuille
2015-01-26  5:14 ` Pieter Wuille
2015-01-26 18:35   ` Gregory Maxwell
2015-01-28  6:24     ` Wladimir
2015-02-06 21:38     ` Pieter Wuille

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