From: ZmnSCPxj <ZmnSCPxj@protonmail•com>
To: Russell O'Connor <roconnor@blockstream•com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Beyond Jets: Microcode: Consensus-Critical Jets Without Softforks
Date: Tue, 22 Mar 2022 16:39:10 +0000 [thread overview]
Message-ID: <b44RnTZqVC01psPp8Iijmj2oGLcm7CnG56UaT5xEvtNkVVOfK4YAka_jf-zey7_Kkou7ewNWbGx9sBDoF3Fu9OA2aL2FCVY4u0ZI6geOCpU=@protonmail.com> (raw)
In-Reply-To: <CAMZUoKnC0f=FCjSa9oNMhXob+P6OaMdzUKWbhAMty2Xub-40TA@mail.gmail.com>
Good morning Russell,
> Thanks for the clarification.
>
> You don't think referring to the microcode via its hash, effectively using 32-byte encoding of opcodes, is still rather long winded?
A microcode is a *mapping* of `OP_` codes to a variable-length sequence of `UOP_` micro-opcodes.
So a microcode hash refers to an entire language of redefined `OP_` codes, not each individual opcode in the language.
If it costs 1 Bitcoin to create a new microcode, then there are only 21 million possible microcodes, and I think about 50 bits of hash is sufficient to specify those with low probability of collision.
We could use a 20-byte RIPEMD . SHA256 instead for 160 bits, that should be more than sufficient with enough margin.
Though perhaps it is now easier to deliberately attack...
Also, if you have a common SCRIPT whose non-`OP_PUSH` opcodes are more than say 32 + 1 bytes (or 20 + 1 if using RIPEMD), and you can fit their equivalent `UOP_` codes into the max limit for a *single* opcode, you can save bytes by redefining some random `OP_` code into the sequence of all the `UOP_` codes.
You would have a hash reference to the microcode, and a single byte for the actual "SCRIPT" which is just a jet of the entire SCRIPT.
Users of multiple *different* such SCRIPTs can band together to define a single microcode, mapping their SCRIPTs to different `OP_` codes and sharing the cost of defining the new microcode that shortens all their SCRIPTs.
Regards,
ZmnSCPxj
next prev parent reply other threads:[~2022-03-22 16:39 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-22 5:37 ZmnSCPxj
2022-03-22 15:08 ` Russell O'Connor
2022-03-22 16:22 ` ZmnSCPxj
2022-03-22 16:28 ` Russell O'Connor
2022-03-22 16:39 ` ZmnSCPxj [this message]
2022-03-22 16:47 ` ZmnSCPxj
2022-03-22 23:11 ` Anthony Towns
2022-03-23 0:20 ` ZmnSCPxj
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