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From: William Casarin <jb55@jb55.com>
To: Achow101 <achow101-lists@achow101.com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP 174 thoughts
Date: Thu, 05 Jul 2018 12:20:32 -0700	[thread overview]
Message-ID: <87in5ttrpb.fsf@jb55.com> (raw)
In-Reply-To: <0BT4A0BFbcfUM9xlYjS-7Cy1zpaI1J9qsIpWH_xgv2ZLhcmxb4Es5KlpMJCvHVEu8BDbBweZ92RHnES5HxDMulRhJkYSZAPi-CgXQ3uwkfY=@achow101.com>


I have another concern with the format. (my original bip comment for some context: [1])

It looks like the one of the reasons I was confused is because you can
only parse the format properly by first deserializing the transaction.
Since there is no "length" field for the key-value map arrays, you must
count the number of transaction input/outputs, and use that as the
number of kv maps to parse.

This is pretty brittle, because now if a Combiner writes the wrong
number of key-value maps that don't align with the number of inputs and
outputs in the transaction, then the psbt will not be able to be
deserialized properly, but is still a valid PSBT. It can't even detect
these situations, because the input and output types share the same enum
values. I don't see anywhere that says the number of key value maps MUST
match the number of inputs/outputs, perhaps it's implied?

I think I think we should either make this explicit in the BIP, add an
array length prefix, or make all (global/input/output) types share the
same enum.

Cheers,
William

[1] https://github.com/bitcoin/bips/pull/694#issuecomment-402812041


  parent reply	other threads:[~2018-07-05 19:20 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-15 23:34 [bitcoin-dev] BIP 174 thoughts Pieter Wuille
2018-06-16 15:00 ` Peter D. Gray
2018-06-19  9:38 ` Jonas Schnelli
2018-06-19 14:20 ` matejcik
2018-06-19 15:20   ` Jonas Schnelli
2018-06-21 20:28     ` Peter D. Gray
2018-06-19 17:16   ` Pieter Wuille
2018-06-21 11:29     ` matejcik
2018-06-21 17:39       ` Pieter Wuille
2018-06-21 11:44     ` Tomas Susanka
2018-06-19 14:22 ` matejcik
2018-06-21  0:39 ` Achow101
2018-06-21 14:32   ` Tomas Susanka
2018-06-21 15:40     ` Greg Sanders
2018-06-21 19:56     ` Peter D. Gray
2018-06-21 21:39       ` Gregory Maxwell
2018-06-22 19:10       ` Pieter Wuille
2018-06-22 22:28         ` Achow101
2018-06-23 17:00           ` William Casarin
2018-06-23 20:33             ` Andrew Chow
2018-06-24  8:19               ` Andrea
2018-06-24  8:28                 ` Andrew Chow
2018-06-24  9:00                   ` Andrea
2018-06-23 18:27           ` Peter D. Gray
2018-06-25 19:47           ` Tomas Susanka
2018-06-25 20:10             ` Jonas Schnelli
2018-06-25 20:30             ` Achow101
2018-06-26 15:33               ` matejcik
2018-06-26 16:58                 ` William Casarin
2018-06-26 17:11                   ` Marek Palatinus
2018-06-27 14:11                   ` matejcik
2018-06-26 20:30                 ` Pieter Wuille
2018-06-27 14:04                   ` matejcik
2018-06-27 15:06                     ` Pieter Wuille
2018-06-29  9:53                       ` matejcik
2018-06-29 19:12                         ` Achow101
2018-06-29 20:31                           ` Peter D. Gray
2018-07-04 13:19                           ` matejcik
2018-07-04 18:35                             ` Achow101
2018-07-05 17:23                               ` Jason Les
2018-07-04 19:09                             ` Pieter Wuille
2018-07-05 11:52                               ` matejcik
2018-07-05 22:06                                 ` Pieter Wuille
2018-07-10 12:10                                   ` matejcik
2018-07-11 18:27                                     ` Pieter Wuille
2018-07-11 20:05                                       ` Gregory Maxwell
2018-07-11 20:54                                         ` [bitcoin-dev] BIP 174 thoughts on graphics vv01f
2018-06-26 21:56                 ` [bitcoin-dev] BIP 174 thoughts Achow101
2018-06-27  6:09                   ` William Casarin
2018-06-27 13:39                     ` Andrea
2018-06-27 17:55                     ` Achow101
2018-06-28 20:42                       ` Rodolfo Novak
2018-07-05 19:20                       ` William Casarin [this message]
2018-07-06 18:59                         ` Achow101
2018-06-20  0:39 Jason Les

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