What was the very initial value of OP_RETURN?

Question

My understanding is that OP_RETURN was first introduced in v0.9.0 (https://bitcoin.org/en/release/v0.9.0).

This link (https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2014-November/006917.html) mentions "initially supposed to be 80 bytes, but got reduced to 40".

This link (https://github.com/bitcoin/bitcoin/pull/5286) says: "The maximum size for OP_RETURN outputs used to be 80 bytes, then got changed to 40 bytes to be on the safe side".

Pull request https://github.com/bitcoin/bitcoin/pull/3737 talks about reducing it to 40 bytes. Was it ever in the code at 80 bytes prior?

Nick ODell · Accepted Answer · 2016-12-29T01:09:22.583

4

My understanding is that OP_RETURN was first introduced in v0.9.0

No, it was just changed to be standard in 0.9.0. If a transaction is nonstandard, miners running Bitcoin Core with default settings will not mine the transaction.

OP_RETURN has been around since the beginning, in 0.1.0. This was the fragment that implemented OP_RETURN in 0.1.0:

        case OP_RETURN:
        {
            pc = pend;
        }
        break;

Back then, OP_RETURN didn't necessarily cause a script to fail. You could also use it in the scriptSig of a transaction, meaning that you could steal anyone's Bitcoins by pushing a non-zero value and calling OP_RETURN. Ah, those were the days.

edited Dec 29 '16 at 01:09

answered Dec 29 '16 at 00:21

Nick ODell

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Nice. How did you get hold of 0.1.0? Bitcoin github only goes back to 0.1.5? https://github.com/bitcoin/bitcoin/releases?after=v0.2.7 – cloudnthings Dec 29 '16 at 19:53
It also sounds like there was no specific size for OP_RETURN defined back in those days? – cloudnthings Dec 29 '16 at 20:08
@cloudnthings http://bitcoin.stackexchange.com/questions/21964/where-can-i-access-the-original-satoshi-written-bitcoin-code – Nick ODell Dec 29 '16 at 21:35
@cloudnthings Well, there's a max block size of 32 MB, so there's definitely a 32 MB limit. – Nick ODell Dec 29 '16 at 21:44
Hmm, isn't the max block size 1Mb in Core and 2Mb in classic? Where did 32 Mb come from? – cloudnthings Dec 31 '16 at 00:48
@cloudnthings It's 1MB now, but back then it was 32 MB. – Nick ODell Dec 31 '16 at 00:59

What was the very initial value of OP_RETURN?

1 Answers1