From: Daniel Robinson <danrobinson010@gmail•com>
To: "Russell O'Connor" <roconnor@blockstream•io>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>,
Johnson Lau <jl2012@xbt•hk>
Subject: Re: [bitcoin-dev] Implementing Covenants with OP_CHECKSIGFROMSTACKVERIFY
Date: Thu, 03 Nov 2016 07:37:29 +0000 [thread overview]
Message-ID: <CAD438HsZRZcRWu=++3kuvyA5Ns9cU360utJMCyc6bROT-fdcHg@mail.gmail.com> (raw)
In-Reply-To: <CAMZUoKmnkk=q7GkkvA+Q4-r64JCQ+kPRPdoEN8bnAwd2YGMH+Q@mail.gmail.com>
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Really cool!
How about "poison transactions," the other covenants use case proposed by
Möser, Eyal, and Sirer? (I think OP_CHECKSIGFROMSTACKVERIFY will also make
it easier to check fraud proofs, the other prerequisite for poison
transactions.)
Seems a little wasteful to do those two "unnecessary" signature checks, and
to have to construct the entire transaction data structure, just to verify
a single output in the transaction. Any plans to add more flexible
introspection opcodes to Elements, such as OP_CHECKOUTPUTVERIFY?
Really minor nit: "Notice that we have appended 0x83 to the end of the
transaction data"—should this say "to the end of the signature"?
On Thu, Nov 3, 2016 at 12:28 AM Russell O'Connor via bitcoin-dev <
bitcoin-dev@lists•linuxfoundation.org> wrote:
Right. There are minor trade-offs to be made with regards to that design
point of OP_CHECKSIGFROMSTACKVERIFY. Fortunately this covenant
construction isn't sensitive to that choice and can be made to work with
either implementation of OP_CHECKSIGFROMSTACKVERIFY.
On Wed, Nov 2, 2016 at 11:35 PM, Johnson Lau <jl2012@xbt•hk> wrote:
Interesting. I have implemented OP_CHECKSIGFROMSTACKVERIFY in a different
way from the Elements. Instead of hashing the data on stack, I directly put
the 32 byte hash to the stack. This should be more flexible as not every
system are using double-SHA256
https://github.com/jl2012/bitcoin/commits/mast_v3_master
On 3 Nov 2016, at 01:30, Russell O'Connor via bitcoin-dev <
bitcoin-dev@lists•linuxfoundation.org> wrote:
Hi all,
It is possible to implement covenants using two script extensions: OP_CAT
and OP_CHECKSIGFROMSTACKVERIFY. Both of these op codes are already
available in the Elements Alpha sidechain, so it is possible to construct
covenants in Elements Alpha today. I have detailed how the construction
works in a blog post at <
https://blockstream.com/2016/11/02/covenants-in-elements-alpha.html>. As
an example, I've constructed scripts for the Moeser-Eyal-Sirer vault.
I'm interested in collecting and implementing other useful covenants, so if
people have ideas, please post them.
If there are any questions, I'd be happy to answer.
--
Russell O'Connor
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next prev parent reply other threads:[~2016-11-03 7:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 17:30 Russell O'Connor
2016-11-03 3:35 ` Johnson Lau
[not found] ` <E8BB95A5-09B3-443C-B197-29DA3C4767D8@xbt.hk>
2016-11-03 4:19 ` Russell O'Connor
2016-11-03 7:37 ` Daniel Robinson [this message]
2016-11-03 20:02 ` Russell O'Connor
2016-11-04 14:35 ` Tim Ruffing
2016-11-07 19:30 ` Jeremy
2016-11-03 17:42 ` Ryan Grant
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