Oleg Andreev [ARCHIVE] on Nostr: 📅 Original date posted:2015-11-10 📝 Original message:OP_0 gives a zero length ...

📅 Original date posted:2015-11-10
📝 Original message:OP_0 gives a zero length byte array because OP_0 == 0x00 which is equivalent to pushdata with zero length.

OP_EQUAL compares byte strings as-is. So it will push "false" because empty string is not the same as a single-byte string with 0x00 byte in it. Value "false" in turn is encoded as empty string, just like result of OP_0.

> On 06 Nov 2015, at 10:37, Tier Nolan via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org> wrote:
>
> I meant not to use the OP_PUSH opcodes to do the push.
>
> Does OP_0 give a zero length byte array?
>
> Would this script return true?
>
> OP_0
> OP_PUSHDATA1 (length = 1, data = 0)
> OP_EQUAL
>
> The easiest definition is that OP_0 and OP_1 must be used to push the data and not any other push opcodes.
>
>
> On Fri, Nov 6, 2015 at 9:32 AM, Oleg Andreev <oleganza at gmail.com <mailto:oleganza at gmail.com>> wrote:
>
> > One and zero should be defined as arrays of length one. Otherwise, it is still possible to mutate the transaction by changing the length of the array.
> >
> > They should also be minimally encoded but that is covered by previous rules.
>
> These two lines contradict each other. Minimally-encoded "zero" is an array of length zero, not one. I'd suggest defining this explicitly here as "IF/NOTIF argument must be either zero-length array or a single byte 0x01".
>
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20151110/8c16a920/attachment.html>;